# HSEF v5.3 review: NAD+/Sirtuin Aging Hypothesis

> Sources: 60 primary reports; claims: 65; verified: 65; unverified: 0. Verification is bounded attribution. Access: 5 partial-body and 55 complete abstract/status examinations. Cutoff: 2026-10-04. No complete-paper audit or blinded calibration claimed.
>
> **Adversarial review:** Generated by Sol 6.1; adversarially reviewed by Claude Opus 5.5 (Anthropic) on 2026-10-06. 1 corrections applied (see ADVERSARIAL REVIEW AND APPROVAL). Status: **Approved as revised.**

## AT A GLANCE

**NAD decline and bounded NAD/sirtuin functional effects are real evidence; general human aging reversal is unproved. Locked weakest-link scoring returns Β, with Ε for defined animal contributions and human functional endpoints.**

| Level | Confidence | Causal role | Momentum | Stability | Divergence |
|---|---|---|---|---|---|
| Β — Associational | Moderate | reinforcing / stabilizing factor | Mechanistic only | Stable | Contested |

**Deciding experiment:** In baseline-defined older adults, randomize adequate NR/NMN exposure and test prespecified clinical function/disability over meaningful follow-up. Pair this with an adult-selective mechanistic contrast that blocks the proposed sirtuin mediator while preserving NAD repletion and other NAD-dependent routes, with selective rescue and masked outcome assessment. Human exposure instruments or lifelong natural experiments can complement the mediator experiment.

**Belief versus evidence:** Preregistered weakest-link returns Β because SC1 is scored at association/existence level; SC2 and bounded functional SC3 reach Ε, and general primacy SC4 is Γ. This conservative aggregation is preserved even though it can understate the strength of narrower causal contributions. The named primary subclaim SC3 returns Ε for the measured human functional scope. Scope-matched returns Γ: only SC4 carries the central claim's general organismal-aging scope, while SC3 is restricted to baseline-defined trial populations and is reported separately. Neither sensitivity establishes human lifespan or general aging reversal.

**Best-supported rival:** Nutrient-sensing network primacy. Adult, tissue-specific NAD depletion/repletion with sirtuin loss/rescue and clinical function, keeping precursor exposure and non-sirtuin cofactor routes intact, distinguishes exclusive primacy from feedback and parallel pathways.

## COMPETING MECHANISTIC MODELS

**Rank 1: Nutrient-sensing network primacy (Ε).** NAD interventions participate in multiple metabolic and repair pathways. AMPK, vATPase/mTOR and compartment contrasts accompany or replace proposed exclusive sirtuin routes [36,56,58,59]. No one network is fully identified as the primary human aging cause.

**Rank 2: Senescence/CD38 degradation sink (Ε).** Inflammatory senescence drives a modifiable NAD sink. Senescence/CD38 perturbations map degradation and functional feedback [32,34–36,47,48]. CD38 pleiotropy, lifelong knockouts and tissue differences prevent universal initiation claims.

**Rank 3: Sirtuins as bounded stress sensors (Ε).** Particular sirtuins protect particular contexts. SIRT3 epistasis, aged HSC function and worm requirement support constrained roles [32,44,50]. Sirtuin isoforms and tissues differ; general endogenous longevity primacy is not isolated.

**Rank 4: Permissive redox-cofactor availability (Γ).** NAD pools enable several necessary cellular reactions. Human engagement, organ compartment and depletion experiments show availability/turnover rather than one universal aging clock [13,23,59,60]. Cell buffering and variable clinical function mean a restored pool is not sufficient for youthful organismal function.

**Rank 5: NAD decline/sirtuin primacy (Β).** Age-associated NAD loss initiates general aging through limited sirtuin activity. Age-associated decline plus defined NAD/sirtuin functional rescues make a coherent hypothesis [29–32,50]. The registered conjunction includes association, general primacy and human aging reversal; no result identifies all those clauses.

The tournament does not alter the nominal level. Compatible pathways and flexible alternatives are not automatically proved by explaining observations.

## FULL REVIEW

### Registered claim and scope

Age-related NAD+ decline limits sirtuin activity and is a causal driver of organismal aging, so NAD+ precursor repletion restores youthful function and improves human healthspan or lifespan.

The precursor-reversal framing is conjunctive; weakest-link applies to SC1–SC4. Neither blood NAD engagement nor a disease-specific functional result alone establishes general aging reversal.

Selection: public-interest rank 4 from the editorial ranking compiled 2026-09-23; categorical prior verdicts were visible. Private fresh review; earlier documents are preserved.

### Evidence and causal interpretation

The registered hypothesis is a conjunction, and its decomposition was fixed before evidence appraisal. It includes a descriptive age-associated decline, a sirtuin-mediated functional mechanism, human healthspan/lifespan and general longevity primacy. The evidence is stronger for some parts than others. This matters especially because the registered weakest-link rule returns the associative Β of SC1 despite causal Ε for bounded contributions and functional outcomes. The score is transparent but should not be read as denying those interventions.

Human skin and brain studies associate age with lower NAD or altered redox balance [29,30]. Animal data add tissue and inflammation detail [31,32,34,35,50]. These measurements support age-related change in specified compartments; they do not show that NAD loss initiates all aging. Cross-sectional sampling, sex, cell composition and assay differences remain relevant. An age difference is also not evidence that every patient is deficient in the same compartment.

The CD38/SIRT3 experiment supplies unusually useful genetic discrimination. Aged CD38-knockout mice retain higher NAD and better glucose tolerance; adding SIRT3 deletion removes functional glucose and mitochondrial benefits despite high NAD [32]. The selected primary Results paragraph directly establishes this dissociation. Thus restoration of NAD alone is insufficient in that setting, and SIRT3 contributes causally. Lifelong knockout and mixed background constrain adult-onset inference without erasing the observed epistasis.

Worm NAD supplementation and sir-2.1 dependence provide a second organismal route [50]. Trigonelline experiments combine precursor routing, worm sirtuin-dependent function/lifespan and mouse muscle outcomes [52]. Other NMN/NR interventions affect stem cells, reproduction, tissue barrier or exercise measures [33,36,37,46–49,53,54]. These are credible functional contributions in particular settings. Their varying mediators and exposure routes do not establish one universally limiting NAD-sirtuin clock.

Direction is a feedback question. Senescence-associated inflammatory signals recruit CD38-positive macrophages and drive NAD degradation [34,35]. CD38 inhibition can improve function through NAD-dependent pathways [36], but sirtuins, AMPK, PARPs and other signaling also move. A cardiac vATPase/mTOR route and compartment-depletion experiments show alternatives to exclusive sirtuin causality [56,59]. Senescence can cause NAD loss while NAD availability still modifies downstream dysfunction.

The positive human literature must also remain visible. NICE reported a 17.6-m NR-placebo walking improvement [7]. Its primary body specifies a one-sided P=.08 and prespecified phase II alpha .10, so this meets its chosen criterion. It is not a conventional two-sided .05 confirmatory effect. The second resveratrol-combination contrast was null; no multiplicity correction was applied, and stronger adherence-subset effects were post hoc. The separately examined correction restores missing trial registration text rather than altering results.

Small NMN trials provide other bounded functional signals: secondary six-minute walking/quality of life, ventilatory thresholds with exercise, and secondary walking after a null primary stepping endpoint [14,15,19]. These support SC3 Ε for measured baseline-defined functions, with moderate confidence. They do not show general disability reduction, long-term disease-free survival or lifespan extension. A within-group change, largest effect size or unvalidated blood-age output cannot supply that missing outcome.

The prediabetic-women study improves the mechanistic picture without proving broad healthspan [13]. NMN improved muscle insulin sensitivity; steady-state muscle NAD did not rise, although turnover metabolites did. Liver and adipose sensitivity did not improve. The proposed PDGFR pathway was not selectively manipulated in humans, and sirtuin necessity was not tested. The result is a metabolic contribution, not a demonstrated survival effect.

Several well-controlled studies limit universality. Blood NAD engagement in MCI did not improve cognition; its imaging signal did not survive multiplicity [1]. CKD exercise endpoints were null [6]. A high-dose NMN study changed metabolic measures without strength, endurance or stair-power benefit [16]. Obese-men NR studies found no sensitivity or muscle mitochondrial benefit and share one trial [25–27]. Older diabetic men and NR-pterostilbene muscle injury studies were also functionally null [21,28]. These are scope boundaries rather than proof of universal inefficacy.

General sirtuin longevity primacy is a separate claim. SIRT6 overexpression increases survival in particular mouse backgrounds and flies [39–41], but constitutive construct sufficiency is not adult endogenous necessity. The controlled Sir2 analysis removed earlier worm/fly longevity with matched genetic backgrounds while expression remained high [42]. That correction to a specific paradigm does not invalidate every sirtuin. HSC stress dependence, developmental Sirt6 deficiency and pleiotropic resveratrol highlight distinct contexts [44,45,51].

Authenticated Consensus helped locate a directly relevant CD38 genetic Results passage, which was independently matched to the public primary body. It also returned bibliography chunks for Yoshino; these were rejected as result evidence. This is useful source routing and passage verification, not a measured improvement in review quality. The final score preserves actual positive functions, negative primary outcomes, shared cohorts and the untested bridge to general human aging reversal.

## HYPOTHESIS STATE EVALUATION FRAMEWORK (HSEF v5.3)

<!-- consensus-consistency-2026-10-09 -->
### Consensus provenance reconciliation — 9 October 2026

Case-specific Consensus discovery records were located and linked to this final edition. This supplements the review's provenance; it leaves the original assessed claim, grades and source counts intact. Provider summaries and full-text badges do not establish examination of original primary passages by this reviewer. Source access and incorporation retain the limits stated in the original methods and any dated research update.

Recorded evidence artifacts:

- `deliverables/hsef_v53_popularity_batch_2026-10-04/nad-sirtuin-aging/consensus/evidence-cards.json`
- `deliverables/hsef_v53_popularity_batch_2026-10-04/nad-sirtuin-aging/consensus/evidence-cards.md`
- `deliverables/hsef_v53_popularity_batch_2026-10-04/nad-sirtuin-aging/consensus/rejections.json`
- `deliverables/hsef_v53_popularity_batch_2026-10-04/nad-sirtuin-aging/consensus/targeted-cd38-raw.json`

The located artifacts do not state a reliable source-comparison count. No count is inferred.

A dated adversarial approval record exists for the separately identified nad-sirtuin-aging.review.md (2026-10-06; see edition-approval-audit.json). Its scope is that recorded edition. This supplement has no separate approval and no coverage is inferred from topic identity. No score or confidence change is made by this reconciliation.
<!-- end-consensus-consistency -->


### Subclaim matrix and aggregation

| Subclaim | Scope | Level | Decision |
|---|---|---|---|
| SC1 NAD+ levels decline with age in multiple tissues. | specified human and experimental tissues | Β | SC1 is an existence/age-association subclaim. Human skin and brain age comparisons and animal NAD measurements support a decline in specified tissues, but do not causally identify that decline as an aging initiator [29–32,34,35,50]. Β is the associative evidence level, not a statement that the observed decline is false. |
| SC2 NAD+ decline causally contributes to age-related dysfunction through sirtuin-dependent mechanisms. | specified adult animal tissues and aging phenotypes | Ε | SC2 reaches Ε for defined functional contributions. SIRT3 co-deletion removes aged CD38-knockout glucose benefit despite elevated NAD, worm sir-2.1 is required for tested NAD-dependent longevity, and other adult interventions improve specified function [32,36,50,52,53]. Developmental genetics, compartment and alternative pathways limit general initiation or exclusive mediation. |
| SC3 NR or NMN repletion improves human clinical healthspan or lifespan. | human populations identified at baseline | Ε | SC3 reaches Ε only for measured human functional outcomes in baseline-defined settings. NICE walking meets its liberal prespecified one-sided phase II criterion; small NMN trials report secondary walking/ventilatory signals [7,14,15,19]. Null functional and primary outcomes map limits [1,6,16,21,25–28]. No human lifespan extension, general disability reduction or youthful restoration is demonstrated. |
| SC4 Sirtuins act as general longevity regulators rather than context-specific metabolic response proteins. | adult organismal aging across species and human scope | Γ | SC4 remains Γ for general endogenous longevity primacy. SIRT6 construct sufficiency and fly gain/loss support bounded biology, but constitutive development, background/sex variation and controlled Sir2 failures prevent a general adult-human necessity inference [39–45,51,58]. |

Preregistered aggregation: weakest-link. Preregistered weakest-link returns Β because SC1 is scored at association/existence level; SC2 and bounded functional SC3 reach Ε, and general primacy SC4 is Γ. This conservative aggregation is preserved even though it can understate the strength of narrower causal contributions. The named primary subclaim SC3 returns Ε for the measured human functional scope. Scope-matched returns Γ: only SC4 carries the central claim's general organismal-aging scope, while SC3 is restricted to baseline-defined trial populations and is reported separately. Neither sensitivity establishes human lifespan or general aging reversal. Sensitivities: weakest-link Β; primary-subclaim Ε; scope-matched Γ.

### Decisive-perturbation inventory and causal tally

[1] NR increased blood NAD in a randomized MCI pilot without improving cognition; the CBF signal did not withstand multiplicity correction. Safety and exploratory methylation changes do not demonstrate clinical cognitive or aging reversal.

[5] NR changed the muscle NAD metabolome and inflammatory markers in older men but did not change measured mitochondrial bioenergetics. Metabolite engagement and lower inflammation are distinct from clinical aging reversal.

[6] The CKD randomized crossover found no NR benefit on peak oxygen consumption, work or efficiency despite metabolic changes. This constrains the measured disease and short exposure; it does not prove all NR regimens ineffective.

[7] NICE reported a 17.6-m NR-placebo walking contrast, one-sided P=.08, satisfying its prespecified phase II alpha .10; NR plus resveratrol was null. This is not a conventional two-sided .05 confirmatory result; contrasts lacked multiplicity adjustment and adherence subsets were post hoc. The examined correction restores only the omitted trial registration.

[13] NMN improved muscle insulin sensitivity in randomized prediabetic postmenopausal women; muscle steady-state NAD did not increase although turnover metabolites did. Hepatic and adipose insulin sensitivity did not improve; selective human sirtuin or PDGFR mediation was not tested, and metabolic sensitivity is not lifespan.

[14] A randomized NMN dose trial reported secondary six-minute-walk and quality-of-life benefits alongside blood NAD increases. Small dose groups, multiple endpoints, short duration and unvalidated blood-age algorithms prevent a general lifespan or aging-reversal claim.

[15] NMN plus exercise improved ventilatory-threshold measures in recreational runners while VO2max did not improve. Young/middle-aged trained context, small dose groups and co-exercise do not establish general anti-aging efficacy.

[16] MIB626 changed blood NAD, weight and selected vascular/metabolic measures but not measured strength, fatigue, aerobic capacity, stair power or insulin sensitivity. Molecular engagement is dissociated from these short-term functional endpoints.

[17] NMN increased serum nicotinamide without a significant between-group arterial-stiffness benefit. Blood engagement and an exploratory subgroup cannot replace the null primary contrast.

[19] A randomized NMN trial missed its primary stepping endpoint while showing secondary walking and sleep signals. Secondary outcomes support bounded investigation but do not convert the primary endpoint into a positive confirmatory trial.

[21] A small 24-week trial in older diabetic men found no grip-strength or walking benefit; the frailty difference did not meet conventional significance. The small trial does not establish equivalence or lack of effect in all baseline contexts.

[25] Randomized NR in obese men did not improve insulin sensitivity, metabolism or body composition. Dose, sex and baseline disease constrain the negative result; blood exposure does not prove muscle compartment engagement.

[26] The same obese-men NR trial found no muscle NAD, respiration or mitochondrial morphology improvement, with lower NAMPT expression. This is a shared-cohort mechanistic follow-up, not an independent efficacy trial.

[27] The same randomized obese-men NR cohort showed no pancreatic/incretin response benefit. Shared participants do not add an independent causal replication.

[28] Randomized NR-pterostilbene did not improve muscle-injury regeneration, strength or muscle-stem-cell outcomes in older adults. A bundled preparation and injury protocol cannot isolate NR alone or all aging outcomes.

[31] Mouse NAD decline and repletion were linked to a SIRT1-dependent pseudohypoxic mitochondrial response. Mitochondrial molecular rescue alone does not prove organismal aging reversal; this paper remains abstract-level in this review.

[32] In aged mice, CD38 loss elevated NAD and improved glucose tolerance; SIRT3 co-deletion removed functional and mitochondrial benefits despite elevated NAD. Lifelong double knockout, mixed genetic background and CD38 pleiotropy limit adult-onset and general-human inference.

[33] Long-term NMN improved several age-associated activity, metabolic and ocular functions in mice. Not a mortality-extension trial and not isolated proof of one required sirtuin across species.

[34] Senescent-cell inflammatory signals promoted CD38-positive macrophages and age-associated NAD loss. This places senescence/inflammation upstream of a NAD sink; it does not identify NAD decline as the universal initiator. Linked erratum detail was not examined.

[35] Senescence ablation and ecto-CD38 experiments linked inflammatory tissue context to NAD degradation and precursor availability. Functional CD38 feedback does not by itself establish general sirtuin-mediated longevity primacy.

[36] The CD38 inhibitor 78c improved age-associated glucose, exercise/muscle and cardiac measures; NAD-synthesis inhibition reversed benefit. Several NAD-dependent and non-sirtuin signaling pathways change; this is not exclusive sirtuin mediation or human aging efficacy.

[37] NR improved mouse muscle-stem-cell regeneration and other stem-cell measures, with a reported lifespan effect. Single-model rescue does not prove a general human aging driver or one required endogenous sirtuin.

[38] Nicotinamide improved selected high-fat-diet health measures without extending mouse lifespan. Different precursor, diet and tissue NAD response limit direct falsification of all NR/NMN protocols.

[39] Constitutive SIRT6 overexpression extended median survival in both sexes on B6; SIRT1 overexpression did not add median-survival benefit. Developmental transgene sufficiency is not adult endogenous necessity or human aging primacy.

[40] SIRT6-transgenic mice showed male-specific lifespan extension in the earlier background. Sex/background differences and constitutive overexpression constrain generalization and endogenous necessity.

[41] Fly Sirt6 gain/loss and Myc-linked contrasts affected lifespan and physiology. Developmental expression and species scope do not establish adult human longevity regulation.

[42] Genetic-background and matched-transgenic controls removed previously attributed worm/fly Sir2-overexpression longevity; elevated expression persisted. This challenges those paradigms and proposed DR necessity, not every sirtuin protein or all later SIRT6 results.

[44] SIRT3 affected aged or stressed hematopoietic-stem-cell regeneration while being dispensable for tested young homeostasis. A transplantation/stress function is not universal organismal aging necessity.

[45] LINE1/NRTI contrasts improved severe Sirt6-deficient growth and survival phenotypes. Constitutive deficiency and progeroid development are distinct from reversing normal adult aging.

[46] Endothelial CX43/PARP1/NMN/SIRT3 experiments affected aged blood-brain-barrier dysfunction. A specific vascular endpoint and linked correction not fully examined do not establish human organismal longevity.

[47] CD38 genetic/pharmacological contrasts preserved age-associated ovarian function and fertility. Reproductive function is a bounded health phenotype, not overall lifespan or human fertility efficacy.

[48] CD38/MCU contrasts rescued aged hematopoietic function but showed different CD38 roles in young proliferation. Age and lineage dependence argue against universal inhibition independent of tissue state.

[49] NMN improved meiotic, fertilization and ovulatory functions in aged mouse oocytes. Not a trial of efficacy in older women or direct survival extension.

[50] NAD repletion extended worm lifespan through sir-2.1-dependent and mitochondrial-stress/FOXO pathways. Worm genetic specificity does not establish a universally limiting human NAD-sirtuin aging mechanism.

[51] Resveratrol improved health and survival of high-calorie-fed middle-aged mice. Diet rescue and a pleiotropic compound are not unique endogenous-sirtuin proof or an NR/NMN trial.

[52] Trigonelline tracer and perturbation work linked NAD/sirtuin-dependent worm function/lifespan and improved aged-mouse muscle performance. Human sarcopenia association is not randomized human efficacy; precursor routing does not identify all aging mediation.

[53] NMN improved diet/age-associated mouse glucose dysfunction with partially SIRT1-linked mechanisms. Disease, diet and sex context constrain inference to a general aging initiator.

[54] Adipose NAMPT manipulation, NMN rescue and antibody contrasts linked an endocrine NAD/sirtuin circuit to hypothalamic activity and function. Specified tissue communication does not prove general organismal longevity primacy.

[56] NMN improved diet-associated cardiac function through vATPase/mTOR and metabolic contrasts. An experimentally narrowed alternative route argues against exclusive sirtuin mediation; not general human aging reversal.

[57] NR improved cognition/synapse and inflammatory phenotypes in APP/PS1 mice, with cGAS-STING involvement. Disease-model/cell mechanism does not establish human AD efficacy or a general sirtuin aging driver.

[58] LCA/TULP3/sirtuin-vATPase-AMPK contrasts altered worm/fly lifespan and aged-mouse muscle performance. Allosteric activation and overexpression are not proof that age-related NAD decline initiates aging.

[59] Engineered compartmental NAD depletion showed buffering and differential vulnerability when mitochondria were targeted. Cultured-cell tolerance or failure is not an organismal aging or clinical healthspan endpoint.

[60] NMN/NR tracer experiments identified enterohepatic and microbial deamidation routes in mice. Delivery routing does not establish functional aging efficacy or in-vivo human mediation.

Tally: 43 discriminating contrasts. Null and negative contrasts are discriminators, not positive threshold crossings. Reports and replications are not independent causal lines. Discriminating positive and null contrasts are not all successful aging-reversal tests. Reports from one NR obesity cohort are a single intervention family; rare-disease and young-runner results do not prove healthy-aging efficacy.

### Cap audit, precedence and Β/Γ/Δ boundary

Narrow functional intervention and genetic epistasis can reach Ε in their actual scope. An isolated marker or transgene leg is not re-capped over a convergent set. Here the general endogenous-primacy clause is still construct-heavy and unisolated. SC1 is separately preregistered as existence/association; its Β does not demote the SC2/SC3 causal contributions. The resulting weakest-link score is an aggregation sensitivity, not a blanket dismissal.

Gamma hard-rule audit: NAD level change measurements alone, mitochondrial metrics alone and senescence marker changes alone cap isolated surrogate inferences. SC2 includes functional worm and aged-mouse contrasts, and SC3 includes actual walking/ventilatory outcomes: neither assembled set is honestly described as biomarkers only. Single-species/strain legs constrain generalization, not the whole cross-system set. Constitutive transgene sufficiency cannot identify endogenous general longevity necessity.

SC1 cap: “Pure association evidence — however large, however replicated — cannot exceed Β.” SC1 is an existence/age-association subclaim. Human skin and brain age comparisons and animal NAD measurements support a decline in specified tissues, but do not causally identify that decline as an aging initiator [29–32,34,35,50]. Β is the associative evidence level, not a statement that the observed decline is false.

SC4 cap: “Overexpression in model systems caps at Γ” SC4 remains Γ for general endogenous longevity primacy. SIRT6 construct sufficiency and fly gain/loss support bounded biology, but constitutive development, background/sex variation and controlled Sir2 failures prevent a general adult-human necessity inference [39–45,51,58].

SC1 field-valid definition: “
- Genetic or pharmacologic intervention producing reproducible lifespan/healthspan extension
- Must separate developmental effects from true aging effects
- Biomarker change alone does NOT satisfy this threshold” Positive full-scope result: no. SC1 is an existence/age-association subclaim. Human skin and brain age comparisons and animal NAD measurements support a decline in specified tissues, but do not causally identify that decline as an aging initiator [29–32,34,35,50]. Β is the associative evidence level, not a statement that the observed decline is false.

SC2 field-valid definition: “
- Genetic or pharmacologic intervention producing reproducible lifespan/healthspan extension
- Must separate developmental effects from true aging effects
- Biomarker change alone does NOT satisfy this threshold” Positive full-scope result: yes. SC2 reaches Ε for defined functional contributions. SIRT3 co-deletion removes aged CD38-knockout glucose benefit despite elevated NAD, worm sir-2.1 is required for tested NAD-dependent longevity, and other adult interventions improve specified function [32,36,50,52,53]. Developmental genetics, compartment and alternative pathways limit general initiation or exclusive mediation.

SC3 field-valid definition: “
- Genetic or pharmacologic intervention producing reproducible lifespan/healthspan extension
- Must separate developmental effects from true aging effects
- Biomarker change alone does NOT satisfy this threshold” Positive full-scope result: yes. SC3 reaches Ε only for measured human functional outcomes in baseline-defined settings. NICE walking meets its liberal prespecified one-sided phase II criterion; small NMN trials report secondary walking/ventilatory signals [7,14,15,19]. Null functional and primary outcomes map limits [1,6,16,21,25–28]. No human lifespan extension, general disability reduction or youthful restoration is demonstrated.

SC4 field-valid definition: “
- Genetic or pharmacologic intervention producing reproducible lifespan/healthspan extension
- Must separate developmental effects from true aging effects
- Biomarker change alone does NOT satisfy this threshold” Positive full-scope result: no. SC4 remains Γ for general endogenous longevity primacy. SIRT6 construct sufficiency and fly gain/loss support bounded biology, but constitutive development, background/sex variation and controlled Sir2 failures prevent a general adult-human necessity inference [39–45,51,58].

### Upward threshold ladder

SC1 Δ: “Requires at least one intervention changing lifespan or healthspan in a way consistent with the hypothesis.” Satisfied: no. For Δ in the broad driver interpretation, selective adult depletion and rescue must change an aging trajectory with composition/assay control; descriptive decline itself remains a different question.

SC2 Δ: “Requires at least one intervention changing lifespan or healthspan in a way consistent with the hypothesis.” Satisfied: yes. 

SC2 Ε: “Requires causal effect in constrained contexts, backgrounds, or species.” Satisfied: yes. 

SC2 Ζ: “Requires:
- Reproducible intervention effects
- Mechanistic narrowing
- Evidence not reducible to general sickness, caloric reduction, or developmental artifacts” Satisfied: no. For Ζ, independently narrow adult-onset endogenous NAD-to-sirtuin mediation across backgrounds/species while excluding intake, developmental, redox and CD38-pleiotropy alternatives.

SC3 Δ: “Requires at least one intervention changing lifespan or healthspan in a way consistent with the hypothesis.” Satisfied: yes. 

SC3 Ε: “Requires causal effect in constrained contexts, backgrounds, or species.” Satisfied: yes. 

SC3 Ζ: “Requires:
- Reproducible intervention effects
- Mechanistic narrowing
- Evidence not reducible to general sickness, caloric reduction, or developmental artifacts” Satisfied: no. For Ζ, independently replicate prespecified clinical function with stronger confirmatory inference and dose/tissue engagement; lifelong clinical aging or survival must be tested separately from short disease-specific walking.

SC4 Δ: “Requires at least one intervention changing lifespan or healthspan in a way consistent with the hypothesis.” Satisfied: no. For Δ, selectively perturb adult endogenous sirtuin activity and demonstrate corresponding aging trajectory, with rescue and non-sirtuin pathways held intact rather than developmental construct sufficiency.

Upper ladder: Exposure instruments, adult-specific genetic rescue, independent drug classes, lifelong natural experiments and dose-response clinical function are eligible equivalents. Current blood dose-response does not identify aging mediation; worms and mice supply narrow causality without a human causal aging instrument. No independent human necessity/sufficiency chain carries the full claim to Ζ.

Independence: No assigned subclaim/model reaches Ζ; independent error exclusion is not claimed from publication count. Human intervention, animal epistasis and age-association measurements are distinct evidence classes, but do not identify the full general human driver. Obese-men NR follow-ups share NCT02303483; gene-manipulation and drug experiments from CD38 programmes can share laboratory assumptions.

### Falsification and pitfalls

Pathway manipulation changes biomarkers but not lifespan/healthspan. Several human trials dissociate molecular engagement from measured function [1,5,6,16,25–28]. Missing survival data are not a demonstrated negative survival result. Additional downgrade: False.

Effects disappear across strains or species. Background-controlled worm/fly Sir2 longevity disappears, while distinct SIRT6 experiments remain positive [39–42]. This contradicts uniformity, not every isoform. Additional downgrade: False.

Necessity fails when the proposed pathway is removed. Alternative vATPase/mTOR pathways undermine exclusive sirtuin mediation [56]; SIRT3 deletion abolishing one benefit is positive narrow epistasis, not a failed necessity test [32]. Additional downgrade: False.

13. Therapeutic effect misread as mechanistic proof. Walking benefit does not identify sirtuin mediation or general human aging reversal.

16. Untested generalization confused with mapped boundaries. Sex, strain, isoform and developmental exposure constrain endogenous adult scope.

21. A universal cap re-applied to a convergent evidence set. The worm and mouse functional contribution set retains Ε; single marker legs do not erase it.

22. Scope fitted to the result. Post-treatment NAD or adherence responders are not prespecified efficacy populations.

### Adversarial steelman: above, then below

The strongest Γ case for the full proposition combines aging association with functional interventions and coherent sirtuin epistasis. That is scientifically more informative than correlation alone. Under the locked weakest-link decomposition, however, SC1 is the age-association existence item and remains Β; changing the aggregation retrospectively would hide this methodological limitation.

An Α characterization would reduce the programme to an aging narrative. Direct age measurements, molecular engagement, functional interventions and genetic epistasis refute that characterization. The broader aging-reversal claim remains unproved without making the entire evidence base anecdotal.

Retain Β under the registered aggregation, while exposing the Ε primary-subclaim sensitivity. Reject Α because observed decline and causal contributions are empirical. Do not retrospectively change the claim or rule to obtain Γ.

### Final score, causal direction and M/S/D

Preregistered weakest-link returns Β because SC1 is scored at association/existence level; SC2 and bounded functional SC3 reach Ε, and general primacy SC4 is Γ. This conservative aggregation is preserved even though it can understate the strength of narrower causal contributions. The named primary subclaim SC3 returns Ε for the measured human functional scope. Scope-matched returns Γ: only SC4 carries the central claim's general organismal-aging scope, while SC3 is restricted to baseline-defined trial populations and is reported separately. Neither sensitivity establishes human lifespan or general aging reversal.

Direction is mixed feedback rather than solely downstream: senescence/CD38 inflammation produces NAD loss, but NAD/CD38 manipulation also changes functional outcomes (step 1 no sole consequence; step 2 causal dependency present). General initiation, prevention and rate limitation are not jointly established (step 3). Essential cofactor availability does not prove that age-related depletion is required for aging (step 4). Defined deficits amplify or maintain dysfunction initiated by tissue, inflammatory and metabolic changes, matching step 5.

Momentum: Mechanistic only. Completed 2024–2026 compartment, trigonelline, precursor-routing and endocrine/vascular programmes [46,48,52,56,59,60,23] test specific mechanisms. No currently pending boundary-crossing clinical aging trial was verified.

Stability: Stable. No specifically verified pending general-aging clinical trajectory or selective human sirtuin-mediation result identified in this bounded search. Completed reports are not pending triggers.

Divergence: Contested; no single implied-level arithmetic. These dimensions do not change level or confidence.

## PROPOSED DECISIVE EXPERIMENTS

In baseline-defined older adults, randomize adequate NR/NMN exposure and test prespecified clinical function/disability over meaningful follow-up. Pair this with an adult-selective mechanistic contrast that blocks the proposed sirtuin mediator while preserving NAD repletion and other NAD-dependent routes, with selective rescue and masked outcome assessment. Human exposure instruments or lifelong natural experiments can complement the mediator experiment.

Readout: Clinical function, disability, incident age-related disease and survival, separately from blood/tissue NAD and sirtuin activity. Controls: Tissue engagement, age/sex/disease context, intake, co-interventions, multiplicity and mediation specificity; no responder-selected inference. Supporting: Replicated clinical aging benefit lost specifically with sirtuin blockade and restored by mediator rescue. Falsifying: Adequate engagement without clinical benefit, or preserved benefit when the nominal sirtuin mediator is removed.

## KNOWLEDGE GAPS

Which tissue compartments decline with age and why?

Which NAD functions require which sirtuin isoforms in adults?

Can narrow walking signals survive independent confirmatory testing?

Do clinical benefits change disability or survival rather than short physiology?

How do inflammation, precursor routing and non-sirtuin cofactors alter causality?

## REVIEWER NOTES

Sixty actual primary abstract/status examinations and five selected primary-body examinations. The NICE correction was separately read in full: it restores the trial registration text and does not change its statistical result. Other linked correction details remain incompletely examined; fine corrected numerical claims are not load bearing. The Yoshino Consensus chunks were bibliography and rejected as result evidence. CD38/SIRT3 Consensus passage was matched to the primary Results section. This is evidence assessment, not supplement advice.

Search leads, reviews, protocols and correction notices do not pad the primary count. Downloaded XML does not earn examination credit. Linked notices remain attached; unexamined correction details limit inference. This is a coordinator source/claim consistency assessment, not independent blinded calibration.

## ADVERSARIAL REVIEW AND APPROVAL

**Authoring model:** Sol 6.1. **Adversarial reviewer:** Claude Opus 5.5 (Anthropic). **Date:** 2026-10-06.

**Scope of checks:** All 60 reference PMIDs re-fetched with the PubMed MCP tool get_article_metadata and cross-checked against NCBI E-utilities (title, first author, journal, year, DOI): 60/60 correct; no retraction or expression of concern; 4 linked errata, all disclosed on the cards. 17 load-bearing claims spot-checked against PubMed abstracts: refs 1, 6, 7, 13, 14, 15, 16, 19, 21, 25, 29, 32, 39, 42, 50, 52, 55. Scoring logic checked against SKILL.md Step 3, hsef-framework.md and the index entry for NAD/sirtuins (which prescribes weakest-link and records SC1 as Β-level association).

**Findings and corrections**

| ID | Severity | Location | Original → corrected | Evidence |
|---|---|---|---|---|
| NS-1 | Major | Subclaim matrix and aggregation; AT A GLANCE 'Belief versus evidence'; Final score; scorecard aggregation_derivation, aggregation_alternatives.scope_matched_would_return, final_score.rationale | Reported scope-matched sensitivity 'Ε' → 'Γ', with a sentence stating why (SC4 is the only full-scope subclaim; SC3 is restricted to baseline-defined trial populations) | SKILL.md Step 3: scope-matched 'overall equals the highest subclaim whose scope matches the central claim's scope; narrower subclaims reported separately'. The review's own SC3 scope is 'human populations identified at baseline' and its rationale says Ε holds 'only for measured human functional outcomes in baseline-defined settings', so SC3 cannot carry the general claim; SC4's scope is 'adult organismal aging across species and human scope' at Γ. Headline level is unchanged because the preregistered rule is weakest-link (Β). |

**Rejected findings (checked, no change)**

- Headline Β: weakest-link is prescribed by hypothesis-index.md for this hypothesis and is applied as written to the lowest subclaim (SC1 Β), which the index itself records as Β-level association. No framework text forces a different letter.
- SC1 Β rather than Γ: the subclaim is descriptive existence/age-association, and universal cap 2 bars more without causal manipulation.
- SC2 Ε and SC3 Ε: the CD38/SIRT3 epistasis and the human functional trials support context-specific causality in the stated scopes; the index's Γ biomarker cap for SC3 is lifted only by phenotype endpoints, which the walking and insulin-sensitivity results supply within their baseline-defined populations.
- NICE 6-minute-walk description (17.6 m, one-sided inference, resveratrol arm null), the prediabetic-women NMN result (muscle but not hepatic/adipose sensitivity), the MCI null, the MIB626 functional nulls, the Sir2-overexpression background-control reversal and SIRT6 transgenic survival: all match the abstracts.
- Year differences for refs 1, 8, 9, 14, 18 (print vs e-pub, one year apart): acceptable under convention.

**Residual limitations**

- Verification was mostly at abstract depth; the 5 receipted partial-body passages were not re-read here, including the NICE one-sided alpha statement, which rests on the recorded body section.
- Scorecard provenance_header.generated_by reads 'Codex; HSEF v5.3' and was not altered.
- Batch OVERVIEW.md repeats the old sensitivity wording and must be updated by the lead.

**Approval:** Following adversarial review and the corrections listed above, the revised document is approved. — Claude Opus 5.5 (Anthropic), 2026-10-06.

## REFERENCES

1. Orr ME, Kotkowski E, Ramirez P et al. A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment. GeroScience. 2024. [PMID 37994989](https://pubmed.ncbi.nlm.nih.gov/37994989/). DOI: 10.1007/s11357-023-00999-9. Access: abstract_metadata. Study: NCT02942888.

2. Brakedal B, Dölle C, Riemer F et al. The NADPARK study: A randomized phase I trial of nicotinamide riboside supplementation in Parkinson's disease. Cell metabolism. 2022. [PMID 35235774](https://pubmed.ncbi.nlm.nih.gov/35235774/). DOI: 10.1016/j.cmet.2022.02.001. Access: abstract_metadata. Study: PMID35235774.

3. Norheim KL, Ben Ezra M, Heckenbach I et al. Effect of nicotinamide riboside on airway inflammation in COPD: a randomized, placebo-controlled trial. Nature aging. 2024. [PMID 39548320](https://pubmed.ncbi.nlm.nih.gov/39548320/). DOI: 10.1038/s43587-024-00758-1. Access: abstract_metadata. Study: PMID39548320.

4. Martens CR, Denman BA, Mazzo MR et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nature communications. 2018. [PMID 29599478](https://pubmed.ncbi.nlm.nih.gov/29599478/). DOI: 10.1038/s41467-018-03421-7. Access: abstract_metadata. Study: PMID29599478.

5. Elhassan YS, Kluckova K, Fletcher RS et al. Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures. Cell reports. 2019. [PMID 31412242](https://pubmed.ncbi.nlm.nih.gov/31412242/). DOI: 10.1016/j.celrep.2019.07.043. Access: abstract_metadata. Study: PMID31412242.

6. Ahmadi A, Begue G, Valencia AP et al. Randomized crossover clinical trial of coenzyme Q10 and nicotinamide riboside in chronic kidney disease. JCI insight. 2023. [PMID 37159264](https://pubmed.ncbi.nlm.nih.gov/37159264/). DOI: 10.1172/jci.insight.167274. Access: abstract_metadata. Study: PMID37159264.

7. McDermott MM, Martens CR, Domanchuk KJ et al. Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial. Nature communications. 2024. [PMID 38871717](https://pubmed.ncbi.nlm.nih.gov/38871717/). DOI: 10.1038/s41467-024-49092-5. Access: full_text_partial. Study: NCT03743636.

8. Vreones M, Mustapic M, Moaddel R et al. Oral nicotinamide riboside raises NAD+ and lowers biomarkers of neurodegenerative pathology in plasma extracellular vesicles enriched for neuronal origin. Aging cell. 2023. [PMID 36515353](https://pubmed.ncbi.nlm.nih.gov/36515353/). DOI: 10.1111/acel.13754. Access: abstract_metadata. Study: NCT02921659.

9. Presterud R, Deng WH, Wennerström AB et al. Long-Term Nicotinamide Riboside Use Improves Coordination and Eye Movements in Ataxia Telangiectasia. Movement disorders : official journal of the Movement Disorder Society. 2024. [PMID 37899683](https://pubmed.ncbi.nlm.nih.gov/37899683/). DOI: 10.1002/mds.29645. Access: abstract_metadata. Study: PMID37899683.

10. Conze D, Brenner C, Kruger CL et al. Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults. Scientific reports. 2019. [PMID 31278280](https://pubmed.ncbi.nlm.nih.gov/31278280/). DOI: 10.1038/s41598-019-46120-z. Access: abstract_metadata. Study: PMID31278280.

11. Berven H, Kverneng S, Sheard E et al. NR-SAFE: a randomized, double-blind safety trial of high dose nicotinamide riboside in Parkinson's disease. Nature communications. 2023. [PMID 38016950](https://pubmed.ncbi.nlm.nih.gov/38016950/). DOI: 10.1038/s41467-023-43514-6. Access: abstract_metadata. Study: NCT05344404.

12. Zhou B, Wang DD, Qiu Y et al. Boosting NAD level suppresses inflammatory activation of PBMCs in heart failure. The Journal of clinical investigation. 2020. [PMID 32790648](https://pubmed.ncbi.nlm.nih.gov/32790648/). DOI: 10.1172/JCI138538. Access: abstract_metadata. Study: PMID32790648.

13. Yoshino M, Yoshino J, Kayser BD et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science (New York, N.Y.). 2021. [PMID 33888596](https://pubmed.ncbi.nlm.nih.gov/33888596/). DOI: 10.1126/science.abe9985. Access: full_text_partial. Study: PMID33888596.

14. Yi L, Maier AB, Tao R et al. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. GeroScience. 2023. [PMID 36482258](https://pubmed.ncbi.nlm.nih.gov/36482258/). DOI: 10.1007/s11357-022-00705-1. Access: abstract_metadata. Study: PMID36482258.

15. Liao B, Zhao Y, Wang D et al. Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study. Journal of the International Society of Sports Nutrition. 2021. [PMID 34238308](https://pubmed.ncbi.nlm.nih.gov/34238308/). DOI: 10.1186/s12970-021-00442-4. Access: abstract_metadata. Study: PMID34238308.

16. Pencina KM, Valderrabano R, Wipper B et al. Nicotinamide Adenine Dinucleotide Augmentation in Overweight or Obese Middle-Aged and Older Adults: A Physiologic Study. The Journal of clinical endocrinology and metabolism. 2023. [PMID 36740954](https://pubmed.ncbi.nlm.nih.gov/36740954/). DOI: 10.1210/clinem/dgad027. Access: abstract_metadata. Study: PMID36740954.

17. Katayoshi T, Uehata S, Nakashima N et al. Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial. Scientific reports. 2023. [PMID 36797393](https://pubmed.ncbi.nlm.nih.gov/36797393/). DOI: 10.1038/s41598-023-29787-3. Access: abstract_metadata. Study: PMID36797393.

18. Irie J, Inagaki E, Fujita M et al. Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men. Endocrine journal. 2020. [PMID 31685720](https://pubmed.ncbi.nlm.nih.gov/31685720/). DOI: 10.1507/endocrj.EJ19-0313. Access: abstract_metadata. Study: PMID31685720.

19. Morifuji M, Higashi S, Ebihara S et al. Ingestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults in a double-blind randomized, placebo-controlled study. GeroScience. 2024. [PMID 38789831](https://pubmed.ncbi.nlm.nih.gov/38789831/). DOI: 10.1007/s11357-024-01204-1. Access: abstract_metadata. Study: PMID38789831.

20. Kim M, Seol J, Sato T et al. Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study. Nutrients. 2022. [PMID 35215405](https://pubmed.ncbi.nlm.nih.gov/35215405/). DOI: 10.3390/nu14040755. Access: abstract_metadata. Study: PMID35215405.

21. Akasaka H, Nakagami H, Sugimoto K et al. Effects of nicotinamide mononucleotide on older patients with diabetes and impaired physical performance: A prospective, placebo-controlled, double-blind study. Geriatrics & gerontology international. 2023. [PMID 36443648](https://pubmed.ncbi.nlm.nih.gov/36443648/). DOI: 10.1111/ggi.14513. Access: abstract_metadata. Study: PMID36443648.

22. Fukamizu Y, Uchida Y, Shigekawa A et al. Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women. Scientific reports. 2022. [PMID 36002548](https://pubmed.ncbi.nlm.nih.gov/36002548/). DOI: 10.1038/s41598-022-18272-y. Access: abstract_metadata. Study: PMID36002548.

23. Christen S, Redeuil K, Goulet L et al. The differential impact of three different NAD+ boosters on circulatory NAD and microbial metabolism in humans. Nature metabolism. 2026. [PMID 41540253](https://pubmed.ncbi.nlm.nih.gov/41540253/). DOI: 10.1038/s42255-025-01421-8. Access: abstract_metadata. Study: NCT05517122.

24. Yamaguchi S, Irie J, Mitsuishi M et al. Safety and efficacy of long-term nicotinamide mononucleotide supplementation on metabolism, sleep, and nicotinamide adenine dinucleotide biosynthesis in healthy, middle-aged Japanese men. Endocrine journal. 2024. [PMID 38191197](https://pubmed.ncbi.nlm.nih.gov/38191197/). DOI: 10.1507/endocrj.EJ23-0431. Access: abstract_metadata. Study: PMID38191197.

25. Dollerup OL, Christensen B, Svart M et al. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. The American journal of clinical nutrition. 2018. [PMID 29992272](https://pubmed.ncbi.nlm.nih.gov/29992272/). DOI: 10.1093/ajcn/nqy132. Access: abstract_metadata. Study: NCT02303483.

26. Dollerup OL, Chubanava S, Agerholm M et al. Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men. The Journal of physiology. 2020. [PMID 31710095](https://pubmed.ncbi.nlm.nih.gov/31710095/). DOI: 10.1113/JP278752. Access: abstract_metadata. Study: NCT02303483.

27. Dollerup OL, Trammell SAJ, Hartmann B et al. Effects of Nicotinamide Riboside on Endocrine Pancreatic Function and Incretin Hormones in Nondiabetic Men With Obesity. The Journal of clinical endocrinology and metabolism. 2019. [PMID 31390002](https://pubmed.ncbi.nlm.nih.gov/31390002/). DOI: 10.1210/jc.2019-01081. Access: abstract_metadata. Study: NCT02303483.

28. Jensen JB, Dollerup OL, Møller AB et al. A randomized placebo-controlled trial of nicotinamide riboside and pterostilbene supplementation in experimental muscle injury in elderly individuals. JCI insight. 2022. [PMID 35998039](https://pubmed.ncbi.nlm.nih.gov/35998039/). DOI: 10.1172/jci.insight.158314. Access: abstract_metadata. Study: NCT03754842.

29. Massudi H, Grant R, Braidy N et al. Age-associated changes in oxidative stress and NAD+ metabolism in human tissue. PloS one. 2012. [PMID 22848760](https://pubmed.ncbi.nlm.nih.gov/22848760/). DOI: 10.1371/journal.pone.0042357. Access: abstract_metadata. Study: PMID22848760.

30. Zhu XH, Lu M, Lee BY et al. In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences. Proceedings of the National Academy of Sciences of the United States of America. 2015. [PMID 25730862](https://pubmed.ncbi.nlm.nih.gov/25730862/). DOI: 10.1073/pnas.1417921112. Access: abstract_metadata. Study: PMID25730862.

31. Gomes AP, Price NL, Ling AJ et al. Declining NAD(+) induces a pseudohypoxic state disrupting nuclear-mitochondrial communication during aging. Cell. 2013. [PMID 24360282](https://pubmed.ncbi.nlm.nih.gov/24360282/). DOI: 10.1016/j.cell.2013.11.037. Access: abstract_metadata. Study: PMID24360282.

32. Camacho-Pereira J, Tarragó MG, Chini CCS et al. CD38 Dictates Age-Related NAD Decline and Mitochondrial Dysfunction through an SIRT3-Dependent Mechanism. Cell metabolism. 2016. [PMID 27304511](https://pubmed.ncbi.nlm.nih.gov/27304511/). DOI: 10.1016/j.cmet.2016.05.006. Access: full_text_partial. Study: PMID27304511.

33. Mills KF, Yoshida S, Stein LR et al. Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice. Cell metabolism. 2016. [PMID 28068222](https://pubmed.ncbi.nlm.nih.gov/28068222/). DOI: 10.1016/j.cmet.2016.09.013. Access: abstract_metadata. Study: PMID28068222.

34. Covarrubias AJ, Kale A, Perrone R et al. Senescent cells promote tissue NAD+ decline during ageing via the activation of CD38+ macrophages. Nature metabolism. 2020. [PMID 33199924](https://pubmed.ncbi.nlm.nih.gov/33199924/). DOI: 10.1038/s42255-020-00305-3. Access: abstract_metadata. Study: PMID33199924.

35. Chini CCS, Peclat TR, Warner GM et al. CD38 ecto-enzyme in immune cells is induced during aging and regulates NAD+ and NMN levels. Nature metabolism. 2020. [PMID 33199925](https://pubmed.ncbi.nlm.nih.gov/33199925/). DOI: 10.1038/s42255-020-00298-z. Access: abstract_metadata. Study: PMID33199925.

36. Tarragó MG, Chini CCS, Kanamori KS et al. A Potent and Specific CD38 Inhibitor Ameliorates Age-Related Metabolic Dysfunction by Reversing Tissue NAD+ Decline. Cell metabolism. 2018. [PMID 29719225](https://pubmed.ncbi.nlm.nih.gov/29719225/). DOI: 10.1016/j.cmet.2018.03.016. Access: abstract_metadata. Study: PMID29719225.

37. Zhang H, Ryu D, Wu Y et al. NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice. Science (New York, N.Y.). 2016. [PMID 27127236](https://pubmed.ncbi.nlm.nih.gov/27127236/). DOI: 10.1126/science.aaf2693. Access: abstract_metadata. Study: PMID27127236.

38. Mitchell SJ, Bernier M, Aon MA et al. Nicotinamide Improves Aspects of Healthspan, but Not Lifespan, in Mice. Cell metabolism. 2018. [PMID 29514072](https://pubmed.ncbi.nlm.nih.gov/29514072/). DOI: 10.1016/j.cmet.2018.02.001. Access: abstract_metadata. Study: PMID29514072.

39. Roichman A, Elhanati S, Aon MA et al. Restoration of energy homeostasis by SIRT6 extends healthy lifespan. Nature communications. 2021. [PMID 34050173](https://pubmed.ncbi.nlm.nih.gov/34050173/). DOI: 10.1038/s41467-021-23545-7. Access: full_text_partial. Study: PMID34050173.

40. Kanfi Y, Naiman S, Amir G et al. The sirtuin SIRT6 regulates lifespan in male mice. Nature. 2012. [PMID 22367546](https://pubmed.ncbi.nlm.nih.gov/22367546/). DOI: 10.1038/nature10815. Access: abstract_metadata. Study: PMID22367546.

41. Taylor JR, Wood JG, Mizerak E et al. Sirt6 regulates lifespan in Drosophila melanogaster. Proceedings of the National Academy of Sciences of the United States of America. 2022. [PMID 35091469](https://pubmed.ncbi.nlm.nih.gov/35091469/). DOI: 10.1073/pnas.2111176119. Access: abstract_metadata. Study: PMID35091469.

42. Burnett C, Valentini S, Cabreiro F et al. Absence of effects of Sir2 overexpression on lifespan in C. elegans and Drosophila. Nature. 2011. [PMID 21938067](https://pubmed.ncbi.nlm.nih.gov/21938067/). DOI: 10.1038/nature10296. Access: full_text_partial. Study: PMID21938067.

43. Tian X, Firsanov D, Zhang Z et al. SIRT6 Is Responsible for More Efficient DNA Double-Strand Break Repair in Long-Lived Species. Cell. 2019. [PMID 31002797](https://pubmed.ncbi.nlm.nih.gov/31002797/). DOI: 10.1016/j.cell.2019.03.043. Access: abstract_metadata. Study: PMID31002797.

44. Brown K, Xie S, Qiu X et al. SIRT3 reverses aging-associated degeneration. Cell reports. 2013. [PMID 23375372](https://pubmed.ncbi.nlm.nih.gov/23375372/). DOI: 10.1016/j.celrep.2013.01.005. Access: abstract_metadata. Study: PMID23375372.

45. Simon M, Van Meter M, Ablaeva J et al. LINE1 Derepression in Aged Wild-Type and SIRT6-Deficient Mice Drives Inflammation. Cell metabolism. 2019. [PMID 30853213](https://pubmed.ncbi.nlm.nih.gov/30853213/). DOI: 10.1016/j.cmet.2019.02.014. Access: abstract_metadata. Study: PMID30853213.

46. Zhan R, Meng X, Tian D et al. NAD+ rescues aging-induced blood-brain barrier damage via the CX43-PARP1 axis. Neuron. 2023. [PMID 37683629](https://pubmed.ncbi.nlm.nih.gov/37683629/). DOI: 10.1016/j.neuron.2023.08.010. Access: abstract_metadata. Study: PMID37683629.

47. Yang Q, Chen W, Cong L et al. NADase CD38 is a key determinant of ovarian aging. Nature aging. 2024. [PMID 38129670](https://pubmed.ncbi.nlm.nih.gov/38129670/). DOI: 10.1038/s43587-023-00532-9. Access: abstract_metadata. Study: PMID38129670.

48. Song Z, Park SH, Mu WC et al. An NAD+-dependent metabolic checkpoint regulates hematopoietic stem cell activation and aging. Nature aging. 2024. [PMID 39044033](https://pubmed.ncbi.nlm.nih.gov/39044033/). DOI: 10.1038/s43587-024-00670-8. Access: abstract_metadata. Study: PMID39044033.

49. Miao Y, Cui Z, Gao Q et al. Nicotinamide Mononucleotide Supplementation Reverses the Declining Quality of Maternally Aged Oocytes. Cell reports. 2020. [PMID 32755581](https://pubmed.ncbi.nlm.nih.gov/32755581/). DOI: 10.1016/j.celrep.2020.107987. Access: abstract_metadata. Study: PMID32755581.

50. Mouchiroud L, Houtkooper RH, Moullan N et al. The NAD(+)/Sirtuin Pathway Modulates Longevity through Activation of Mitochondrial UPR and FOXO Signaling. Cell. 2013. [PMID 23870130](https://pubmed.ncbi.nlm.nih.gov/23870130/). DOI: 10.1016/j.cell.2013.06.016. Access: abstract_metadata. Study: PMID23870130.

51. Baur JA, Pearson KJ, Price NL et al. Resveratrol improves health and survival of mice on a high-calorie diet. Nature. 2006. [PMID 17086191](https://pubmed.ncbi.nlm.nih.gov/17086191/). DOI: 10.1038/nature05354. Access: abstract_metadata. Study: PMID17086191.

52. Membrez M, Migliavacca E, Christen S et al. Trigonelline is an NAD+ precursor that improves muscle function during ageing and is reduced in human sarcopenia. Nature metabolism. 2024. [PMID 38504132](https://pubmed.ncbi.nlm.nih.gov/38504132/). DOI: 10.1038/s42255-024-00997-x. Access: abstract_metadata. Study: PMID38504132.

53. Yoshino J, Mills KF, Yoon MJ et al. Nicotinamide mononucleotide, a key NAD(+) intermediate, treats the pathophysiology of diet- and age-induced diabetes in mice. Cell metabolism. 2011. [PMID 21982712](https://pubmed.ncbi.nlm.nih.gov/21982712/). DOI: 10.1016/j.cmet.2011.08.014. Access: abstract_metadata. Study: PMID21982712.

54. Yoon MJ, Yoshida M, Johnson S et al. SIRT1-Mediated eNAMPT Secretion from Adipose Tissue Regulates Hypothalamic NAD+ and Function in Mice. Cell metabolism. 2015. [PMID 25921090](https://pubmed.ncbi.nlm.nih.gov/25921090/). DOI: 10.1016/j.cmet.2015.04.002. Access: abstract_metadata. Study: PMID25921090.

55. Grozio A, Mills KF, Yoshino J et al. Slc12a8 is a nicotinamide mononucleotide transporter. Nature metabolism. 2019. [PMID 31131364](https://pubmed.ncbi.nlm.nih.gov/31131364/). DOI: 10.1038/s42255-018-0009-4. Access: abstract_metadata. Study: PMID31131364.

56. Wang S, Han Y, Liu R et al. Glycolysis-Mediated Activation of v-ATPase by Nicotinamide Mononucleotide Ameliorates Lipid-Induced Cardiomyopathy by Repressing the CD36-TLR4 Axis. Circulation research. 2024. [PMID 38422177](https://pubmed.ncbi.nlm.nih.gov/38422177/). DOI: 10.1161/CIRCRESAHA.123.322910. Access: abstract_metadata. Study: PMID38422177.

57. Hou Y, Wei Y, Lautrup S et al. NAD+ supplementation reduces neuroinflammation and cell senescence in a transgenic mouse model of Alzheimer's disease via cGAS-STING. Proceedings of the National Academy of Sciences of the United States of America. 2021. [PMID 34497121](https://pubmed.ncbi.nlm.nih.gov/34497121/). DOI: 10.1073/pnas.2011226118. Access: abstract_metadata. Study: PMID34497121.

58. Qu Q, Chen Y, Wang Y et al. Lithocholic acid binds TULP3 to activate sirtuins and AMPK to slow down ageing. Nature. 2025. [PMID 39695235](https://pubmed.ncbi.nlm.nih.gov/39695235/). DOI: 10.1038/s41586-024-08348-2. Access: abstract_metadata. Study: PMID39695235.

59. Høyland LE, VanLinden MR, Niere M et al. Subcellular NAD+ pools are interconnected and buffered by mitochondrial NAD. Nature metabolism. 2024. [PMID 39702414](https://pubmed.ncbi.nlm.nih.gov/39702414/). DOI: 10.1038/s42255-024-01174-w. Access: abstract_metadata. Study: PMID39702414.

60. Yaku K, Palikhe S, Iqbal T et al. Nicotinamide riboside and nicotinamide mononucleotide facilitate NAD+ synthesis via enterohepatic circulation. Science advances. 2025. [PMID 40117359](https://pubmed.ncbi.nlm.nih.gov/40117359/). DOI: 10.1126/sciadv.adr1538. Access: abstract_metadata. Study: PMID40117359.

## Source-specific evidence cards

### [1] A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment.

**Shows:** NR increased blood NAD in a randomized MCI pilot without improving cognition; the CBF signal did not withstand multiplicity correction.

**Does not show:** Safety and exploratory methylation changes do not demonstrate clinical cognitive or aging reversal.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [2] The NADPARK study: A randomized phase I trial of nicotinamide riboside supplementation in Parkinson's disease.

**Shows:** NADPARK demonstrated variable brain NAD engagement after NR in a small randomized untreated-PD trial.

**Does not show:** Mild clinical changes in post-treatment NAD responders cannot define an unbiased aging-efficacy population.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [3] Effect of nicotinamide riboside on airway inflammation in COPD: a randomized, placebo-controlled trial.

**Shows:** NR reduced the prespecified sputum IL8 inflammatory endpoint in a COPD randomized trial.

**Does not show:** Inflammatory improvement is not a demonstrated functional healthspan or mortality effect.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [4] Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults.

**Shows:** A randomized older-adult crossover established NR blood target engagement and tolerability with suggestive vascular changes.

**Does not show:** Potential blood-pressure and arterial signals require confirmatory outcome separation; no longevity result.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [5] Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures.

**Shows:** NR changed the muscle NAD metabolome and inflammatory markers in older men but did not change measured mitochondrial bioenergetics.

**Does not show:** Metabolite engagement and lower inflammation are distinct from clinical aging reversal.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [6] Randomized crossover clinical trial of coenzyme Q10 and nicotinamide riboside in chronic kidney disease.

**Shows:** The CKD randomized crossover found no NR benefit on peak oxygen consumption, work or efficiency despite metabolic changes.

**Does not show:** This constrains the measured disease and short exposure; it does not prove all NR regimens ineffective.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [7] Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial.

**Shows:** NICE reported a 17.6-m NR-placebo walking contrast, one-sided P=.08, satisfying its prespecified phase II alpha .10; NR plus resveratrol was null.

**Does not show:** This is not a conventional two-sided .05 confirmatory result; contrasts lacked multiplicity adjustment and adherence subsets were post hoc. The examined correction restores only the omitted trial registration.

**Access/status:** Complete primary abstract and linked-status metadata examined. Selected body sections: Sec3, Sec33, Sec34. No complete-paper or supplement audit claimed. ErratumIn: PMID39134546. Subclaims: SC3.

### [8] Oral nicotinamide riboside raises NAD+ and lowers biomarkers of neurodegenerative pathology in plasma extracellular vesicles enriched for neuronal origin.

**Shows:** NR altered NAD and AD-associated signaling measures in neuron-enriched extracellular-vesicle preparations.

**Does not show:** Enrichment is not direct brain sampling, and these changes do not demonstrate clinical cognition or healthspan improvement.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [9] Long-Term Nicotinamide Riboside Use Improves Coordination and Eye Movements in Ataxia Telangiectasia.

**Shows:** An open-label ataxia-telangiectasia programme reported motor improvement relative to historical expectations.

**Does not show:** No randomized counterfactual; a rare syndromic disorder is not ordinary aging.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [10] Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults.

**Shows:** Randomized NR dose groups increased blood NAD with short-term safety assessment.

**Does not show:** Dose target engagement is not a clinical aging outcome.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [11] NR-SAFE: a randomized, double-blind safety trial of high dose nicotinamide riboside in Parkinson's disease.

**Shows:** NR-SAFE established short high-dose tolerability; UPDRS improvement coincided with a shorter interval since levodopa.

**Does not show:** Medication timing limits attribution of the clinical change; no human sirtuin mediation or general aging result.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [12] Boosting NAD level suppresses inflammatory activation of PBMCs in heart failure.

**Shows:** HF patient PBMC assays and a four-patient NR pilot showed cellular respiratory and inflammatory changes.

**Does not show:** Cellular readouts and an uncontrolled pilot do not demonstrate clinical heart-failure efficacy or human healthspan.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [13] Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women.

**Shows:** NMN improved muscle insulin sensitivity in randomized prediabetic postmenopausal women; muscle steady-state NAD did not increase although turnover metabolites did.

**Does not show:** Hepatic and adipose insulin sensitivity did not improve; selective human sirtuin or PDGFR mediation was not tested, and metabolic sensitivity is not lifespan.

**Access/status:** Complete primary abstract and linked-status metadata examined. Selected body sections: BODY. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2, SC3.

### [14] The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial.

**Shows:** A randomized NMN dose trial reported secondary six-minute-walk and quality-of-life benefits alongside blood NAD increases.

**Does not show:** Small dose groups, multiple endpoints, short duration and unvalidated blood-age algorithms prevent a general lifespan or aging-reversal claim.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [15] Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study.

**Shows:** NMN plus exercise improved ventilatory-threshold measures in recreational runners while VO2max did not improve.

**Does not show:** Young/middle-aged trained context, small dose groups and co-exercise do not establish general anti-aging efficacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [16] Nicotinamide Adenine Dinucleotide Augmentation in Overweight or Obese Middle-Aged and Older Adults: A Physiologic Study.

**Shows:** MIB626 changed blood NAD, weight and selected vascular/metabolic measures but not measured strength, fatigue, aerobic capacity, stair power or insulin sensitivity.

**Does not show:** Molecular engagement is dissociated from these short-term functional endpoints.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [17] Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial.

**Shows:** NMN increased serum nicotinamide without a significant between-group arterial-stiffness benefit.

**Does not show:** Blood engagement and an exploratory subgroup cannot replace the null primary contrast.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [18] Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men.

**Shows:** An acute single-arm NMN dose study established short-term pharmacokinetic and safety observations.

**Does not show:** Ten participants and acute exposure do not assess healthspan or efficacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [19] Ingestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults in a double-blind randomized, placebo-controlled study.

**Shows:** A randomized NMN trial missed its primary stepping endpoint while showing secondary walking and sleep signals.

**Does not show:** Secondary outcomes support bounded investigation but do not convert the primary endpoint into a positive confirmatory trial.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [20] Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study.

**Shows:** The four-group older-adult NMN study found timing-related interactions; all groups improved sit-to-stand performance and placebo-PM also improved drowsiness.

**Does not show:** The largest within-group effect is not itself an isolated NMN-placebo efficacy contrast.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [21] Effects of nicotinamide mononucleotide on older patients with diabetes and impaired physical performance: A prospective, placebo-controlled, double-blind study.

**Shows:** A small 24-week trial in older diabetic men found no grip-strength or walking benefit; the frailty difference did not meet conventional significance.

**Does not show:** The small trial does not establish equivalence or lack of effect in all baseline contexts.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [22] Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women.

**Shows:** Four-week high-dose NMN testing assessed tolerability and safety.

**Does not show:** Short safety follow-up does not test clinical aging benefit.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [23] The differential impact of three different NAD+ boosters on circulatory NAD and microbial metabolism in humans.

**Shows:** A 2026 randomized open-label comparison found sustained blood NAD rises with NR/NMN and different acute nicotinamide behavior; ex vivo fermentation suggested a deamidation route.

**Does not show:** Exposure routing and ex vivo microbial metabolism do not demonstrate in-vivo human necessity, sirtuin mediation or clinical aging efficacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2, SC3.

### [24] Safety and efficacy of long-term nicotinamide mononucleotide supplementation on metabolism, sleep, and nicotinamide adenine dinucleotide biosynthesis in healthy, middle-aged Japanese men.

**Shows:** A small single-arm NMN study reported PBMC NAD and exploratory metabolic changes, including a tiny hyperinsulinemic subgroup.

**Does not show:** No randomized counterfactual or validated human aging trajectory.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [25] A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects.

**Shows:** Randomized NR in obese men did not improve insulin sensitivity, metabolism or body composition.

**Does not show:** Dose, sex and baseline disease constrain the negative result; blood exposure does not prove muscle compartment engagement.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [26] Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men.

**Shows:** The same obese-men NR trial found no muscle NAD, respiration or mitochondrial morphology improvement, with lower NAMPT expression.

**Does not show:** This is a shared-cohort mechanistic follow-up, not an independent efficacy trial.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2, SC3.

### [27] Effects of Nicotinamide Riboside on Endocrine Pancreatic Function and Incretin Hormones in Nondiabetic Men With Obesity.

**Shows:** The same randomized obese-men NR cohort showed no pancreatic/incretin response benefit.

**Does not show:** Shared participants do not add an independent causal replication.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [28] A randomized placebo-controlled trial of nicotinamide riboside and pterostilbene supplementation in experimental muscle injury in elderly individuals.

**Shows:** Randomized NR-pterostilbene did not improve muscle-injury regeneration, strength or muscle-stem-cell outcomes in older adults.

**Does not show:** A bundled preparation and injury protocol cannot isolate NR alone or all aging outcomes.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC3.

### [29] Age-associated changes in oxidative stress and NAD+ metabolism in human tissue.

**Shows:** Cross-sectional human skin measurements linked age to NAD depletion and sex-dependent enzyme/activity differences.

**Does not show:** Surgical sampling, tissue composition and age association do not establish an initiating aging mechanism.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1.

### [30] In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences.

**Shows:** Human brain magnetic-resonance measurements associated older age with lower NAD and altered NAD redox balance.

**Does not show:** Cross-sectional assay-derived measures do not identify causal direction or general whole-body NAD depletion.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1.

### [31] Declining NAD(+) induces a pseudohypoxic state disrupting nuclear-mitochondrial communication during aging.

**Shows:** Mouse NAD decline and repletion were linked to a SIRT1-dependent pseudohypoxic mitochondrial response.

**Does not show:** Mitochondrial molecular rescue alone does not prove organismal aging reversal; this paper remains abstract-level in this review.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1, SC2.

### [32] CD38 Dictates Age-Related NAD Decline and Mitochondrial Dysfunction through an SIRT3-Dependent Mechanism.

**Shows:** In aged mice, CD38 loss elevated NAD and improved glucose tolerance; SIRT3 co-deletion removed functional and mitochondrial benefits despite elevated NAD.

**Does not show:** Lifelong double knockout, mixed genetic background and CD38 pleiotropy limit adult-onset and general-human inference.

**Access/status:** Complete primary abstract and linked-status metadata examined. Selected body sections: S7. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1, SC2.

### [33] Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice.

**Shows:** Long-term NMN improved several age-associated activity, metabolic and ocular functions in mice.

**Does not show:** Not a mortality-extension trial and not isolated proof of one required sirtuin across species.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [34] Senescent cells promote tissue NAD+ decline during ageing via the activation of CD38+ macrophages.

**Shows:** Senescent-cell inflammatory signals promoted CD38-positive macrophages and age-associated NAD loss.

**Does not show:** This places senescence/inflammation upstream of a NAD sink; it does not identify NAD decline as the universal initiator. Linked erratum detail was not examined.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. ErratumIn: PMID33303985. Subclaims: SC1, SC2.

### [35] CD38 ecto-enzyme in immune cells is induced during aging and regulates NAD+ and NMN levels.

**Shows:** Senescence ablation and ecto-CD38 experiments linked inflammatory tissue context to NAD degradation and precursor availability.

**Does not show:** Functional CD38 feedback does not by itself establish general sirtuin-mediated longevity primacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1, SC2.

### [36] A Potent and Specific CD38 Inhibitor Ameliorates Age-Related Metabolic Dysfunction by Reversing Tissue NAD+ Decline.

**Shows:** The CD38 inhibitor 78c improved age-associated glucose, exercise/muscle and cardiac measures; NAD-synthesis inhibition reversed benefit.

**Does not show:** Several NAD-dependent and non-sirtuin signaling pathways change; this is not exclusive sirtuin mediation or human aging efficacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [37] NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice.

**Shows:** NR improved mouse muscle-stem-cell regeneration and other stem-cell measures, with a reported lifespan effect.

**Does not show:** Single-model rescue does not prove a general human aging driver or one required endogenous sirtuin.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [38] Nicotinamide Improves Aspects of Healthspan, but Not Lifespan, in Mice.

**Shows:** Nicotinamide improved selected high-fat-diet health measures without extending mouse lifespan.

**Does not show:** Different precursor, diet and tissue NAD response limit direct falsification of all NR/NMN protocols.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [39] Restoration of energy homeostasis by SIRT6 extends healthy lifespan.

**Shows:** Constitutive SIRT6 overexpression extended median survival in both sexes on B6; SIRT1 overexpression did not add median-survival benefit.

**Does not show:** Developmental transgene sufficiency is not adult endogenous necessity or human aging primacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. Selected body sections: Sec3, Sec16. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [40] The sirtuin SIRT6 regulates lifespan in male mice.

**Shows:** SIRT6-transgenic mice showed male-specific lifespan extension in the earlier background.

**Does not show:** Sex/background differences and constitutive overexpression constrain generalization and endogenous necessity.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [41] Sirt6 regulates lifespan in Drosophila melanogaster.

**Shows:** Fly Sirt6 gain/loss and Myc-linked contrasts affected lifespan and physiology.

**Does not show:** Developmental expression and species scope do not establish adult human longevity regulation.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [42] Absence of effects of Sir2 overexpression on lifespan in C. elegans and Drosophila.

**Shows:** Genetic-background and matched-transgenic controls removed previously attributed worm/fly Sir2-overexpression longevity; elevated expression persisted.

**Does not show:** This challenges those paradigms and proposed DR necessity, not every sirtuin protein or all later SIRT6 results.

**Access/status:** Complete primary abstract and linked-status metadata examined. Selected body sections: BODY. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [43] SIRT6 Is Responsible for More Efficient DNA Double-Strand Break Repair in Long-Lived Species.

**Shows:** Across rodent species, SIRT6 sequence/activity tracked DNA-repair performance and longevity.

**Does not show:** Evolutionary correlation and ex vivo sequence effects do not prove lifespan extension by editing an adult organism.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [44] SIRT3 reverses aging-associated degeneration.

**Shows:** SIRT3 affected aged or stressed hematopoietic-stem-cell regeneration while being dispensable for tested young homeostasis.

**Does not show:** A transplantation/stress function is not universal organismal aging necessity.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2, SC4.

### [45] LINE1 Derepression in Aged Wild-Type and SIRT6-Deficient Mice Drives Inflammation.

**Shows:** LINE1/NRTI contrasts improved severe Sirt6-deficient growth and survival phenotypes.

**Does not show:** Constitutive deficiency and progeroid development are distinct from reversing normal adult aging.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [46] NAD+ rescues aging-induced blood-brain barrier damage via the CX43-PARP1 axis.

**Shows:** Endothelial CX43/PARP1/NMN/SIRT3 experiments affected aged blood-brain-barrier dysfunction.

**Does not show:** A specific vascular endpoint and linked correction not fully examined do not establish human organismal longevity.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. ErratumIn: PMID40250429. Subclaims: SC2.

### [47] NADase CD38 is a key determinant of ovarian aging.

**Shows:** CD38 genetic/pharmacological contrasts preserved age-associated ovarian function and fertility.

**Does not show:** Reproductive function is a bounded health phenotype, not overall lifespan or human fertility efficacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [48] An NAD+-dependent metabolic checkpoint regulates hematopoietic stem cell activation and aging.

**Shows:** CD38/MCU contrasts rescued aged hematopoietic function but showed different CD38 roles in young proliferation.

**Does not show:** Age and lineage dependence argue against universal inhibition independent of tissue state.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [49] Nicotinamide Mononucleotide Supplementation Reverses the Declining Quality of Maternally Aged Oocytes.

**Shows:** NMN improved meiotic, fertilization and ovulatory functions in aged mouse oocytes.

**Does not show:** Not a trial of efficacy in older women or direct survival extension.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [50] The NAD(+)/Sirtuin Pathway Modulates Longevity through Activation of Mitochondrial UPR and FOXO Signaling.

**Shows:** NAD repletion extended worm lifespan through sir-2.1-dependent and mitochondrial-stress/FOXO pathways.

**Does not show:** Worm genetic specificity does not establish a universally limiting human NAD-sirtuin aging mechanism.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC1, SC2.

### [51] Resveratrol improves health and survival of mice on a high-calorie diet.

**Shows:** Resveratrol improved health and survival of high-calorie-fed middle-aged mice.

**Does not show:** Diet rescue and a pleiotropic compound are not unique endogenous-sirtuin proof or an NR/NMN trial.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [52] Trigonelline is an NAD+ precursor that improves muscle function during ageing and is reduced in human sarcopenia.

**Shows:** Trigonelline tracer and perturbation work linked NAD/sirtuin-dependent worm function/lifespan and improved aged-mouse muscle performance.

**Does not show:** Human sarcopenia association is not randomized human efficacy; precursor routing does not identify all aging mediation.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [53] Nicotinamide mononucleotide, a key NAD(+) intermediate, treats the pathophysiology of diet- and age-induced diabetes in mice.

**Shows:** NMN improved diet/age-associated mouse glucose dysfunction with partially SIRT1-linked mechanisms.

**Does not show:** Disease, diet and sex context constrain inference to a general aging initiator.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [54] SIRT1-Mediated eNAMPT Secretion from Adipose Tissue Regulates Hypothalamic NAD+ and Function in Mice.

**Shows:** Adipose NAMPT manipulation, NMN rescue and antibody contrasts linked an endocrine NAD/sirtuin circuit to hypothalamic activity and function.

**Does not show:** Specified tissue communication does not prove general organismal longevity primacy.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [55] Slc12a8 is a nicotinamide mononucleotide transporter.

**Shows:** The paper reported Slc12a8-dependent NMN transport using cellular and mouse tracer/genetic experiments.

**Does not show:** The delivery interpretation is contested in linked comments and correction; not a load-bearing human uptake or aging-efficacy result.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. ErratumIn: PMID32694647. Subclaims: SC2.

### [56] Glycolysis-Mediated Activation of v-ATPase by Nicotinamide Mononucleotide Ameliorates Lipid-Induced Cardiomyopathy by Repressing the CD36-TLR4 Axis.

**Shows:** NMN improved diet-associated cardiac function through vATPase/mTOR and metabolic contrasts.

**Does not show:** An experimentally narrowed alternative route argues against exclusive sirtuin mediation; not general human aging reversal.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [57] NAD+ supplementation reduces neuroinflammation and cell senescence in a transgenic mouse model of Alzheimer's disease via cGAS-STING.

**Shows:** NR improved cognition/synapse and inflammatory phenotypes in APP/PS1 mice, with cGAS-STING involvement.

**Does not show:** Disease-model/cell mechanism does not establish human AD efficacy or a general sirtuin aging driver.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [58] Lithocholic acid binds TULP3 to activate sirtuins and AMPK to slow down ageing.

**Shows:** LCA/TULP3/sirtuin-vATPase-AMPK contrasts altered worm/fly lifespan and aged-mouse muscle performance.

**Does not show:** Allosteric activation and overexpression are not proof that age-related NAD decline initiates aging.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC4.

### [59] Subcellular NAD+ pools are interconnected and buffered by mitochondrial NAD.

**Shows:** Engineered compartmental NAD depletion showed buffering and differential vulnerability when mitochondria were targeted.

**Does not show:** Cultured-cell tolerance or failure is not an organismal aging or clinical healthspan endpoint.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.

### [60] Nicotinamide riboside and nicotinamide mononucleotide facilitate NAD+ synthesis via enterohepatic circulation.

**Shows:** NMN/NR tracer experiments identified enterohepatic and microbial deamidation routes in mice.

**Does not show:** Delivery routing does not establish functional aging efficacy or in-vivo human mediation.

**Access/status:** Complete primary abstract and linked-status metadata examined. No complete-paper or supplement audit claimed. none_found. Subclaims: SC2.