The effects of creatine supplementation on cognitive performance-a randomised controlled study.
Level 2 - randomized trial
Preregistered, double-blind, randomized, placebo-controlled crossover trial in humans.
PubMed 37968687 · doi:10.1186/s12916-023-03146-5
What was done
In a preregistered, double-blind, randomized, placebo-controlled crossover trial, 123 participants (approximately half vegetarians and half omnivores) received 5 g of creatine or placebo daily for 6 weeks each. Cognitive performance was assessed using Raven's Advanced Progressive Matrices (RAPM), Backward Digit Span (BDS), and eight exploratory cognitive tasks. Adverse effects were also tracked.
What was found
Bayesian analysis supported a small beneficial effect of creatine. In frequentist testing, the improvement bordered statistical significance for BDS (p = 0.064, η²_p = 0.029) but was not significant for RAPM (p = 0.327, η²_p = 0.008). None of the eight exploratory cognitive tasks showed improvement. Vegetarians did not benefit more than omnivores. Adverse side effects were reported significantly more frequently during creatine supplementation than placebo (p = 0.002, RR = 4.25).
Why it matters
As the largest trial evaluating creatine's cognitive effects to date, these findings indicate that any cognitive enhancement in healthy adults is subtle and task-dependent rather than broad or robust.
Limits
The sample size of 123, while large for this field, had limited power to confirm very small effect sizes. Supplementation was fixed at 5 g/day for 6 weeks, leaving higher loading doses or longer durations unexamined. Testing was conducted in healthy adults, which may not generalize to sleep-deprived, aged, or cognitively impaired populations.
Cited by
- context Studies demonstrate that giving creatine supplements to vegans and vegetarians improves their cognitive function.