# Narration and storyboard draft: NAD Boosters and Human Function

Authored draft, approximately 60–90 seconds; no rendered video claimed.

Does NMN improve physical function as we get older? Raising blood NAD is well supported. Improving useful function is a separate and much less certain question.

One twelve-week trial in adults aged65to75 reports a genuine controlled difference in a secondary four-metre walking test. Its stepping primary, grip and overall performance scores were null. Another small study reported gait signals but had a serious supplement-distribution error and uncorrected exploratory testing. A timing study found improvement within every group; the largest effect in the NMN-afternoon group is not itself proof of superiority to placebo.

Under the registered HSEF v5.3 gate, a real secondary gait outcome can count. We therefore retain a tentative first clinical crossing, Delta, with low confidence. That judgment means a specific early functional signal deserves confirmation. It does not establish a broadly effective strength or exercise treatment, or justify translating blood NAD into years of life.

The nulls matter. A24-week trial in older diabetic men with impaired function did not improve walking or grip. A newly accepted high-dose older-adult trial raised NAD without physical-performance improvement. Younger runners, prediabetic clamp studies and short pharmacodynamic trials answer different questions.

Other drugs also need their own evidence. Nicotinamide riboside has a real peripheral-artery-disease walking trial positive. Several metformin frailty, walking and exercise-addition trials have nulls or unfavorable exercise interactions, while a specific knee-arthritis adjunct trial has a benefit. These molecules are not interchangeable anti-aging therapies.

The decisive next evidence needs reliable allocation, prespecified meaningful function, independent blinded measurement, adequate participants and multiple-testing control. Long-term aging and survival require their own outcomes. Consensus helped locate an important new original study and identify gaps; original Methods, Results and endpoint definitions governed the appraisal.

1. Show the exact claim, grade and confidence.
2. Show selected publication milestones; label experimental systems and clinical endpoints.
3. Contrast the strongest result with its source-specific limitation.
4. End with the boundary experiment and primary-source links.

Use authored schematics; do not depict Consensus meters as causal confidence or reproduce publisher graphics without appropriate permission.