# Creatine and Cognitive Performance

Creatine can preserve selected cognitive performance under experimental energetic stress; evidence for routine enhancement in rested healthy adults is inconsistent, and the brain mediator remains unisolated.

The registered primary-subclaim rule selects SC2. Positive controlled cognitive effects in defined energetic-stress settings support Ε with Moderate confidence. Rested-adult and older-women nulls delimit generalization. Brain target engagement and muscle efficacy do not establish cognitive mediation, dementia prevention or routine enhancement across contexts. Weakest-link returns Γ; primary-subclaim and scope-matched return Ε.

Age, sex, dietary pattern, sleep deprivation, acute hypoxia, dose and delivery route are antecedent-defined modifiers. Positive stress experiments and rested/older-women nulls map a broad context boundary. They do not establish a deterministic responder rule, and no participants are retrospectively excluded as outside scope. Children, rare deficiencies and AD are examined only as transport/biological boundaries.