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Ingredients / Creatine monohydrate
Strong evidence overall 18 articles · reviewed 2 Sep 2026

Creatine monohydrate

Methylguanidinoacetic acid

The most studied sports supplement in existence, and one of the very few whose marketing claims mostly survive contact with the trial record.

What the evidence supports

Strong Strength & power output Hundreds of trials, consistent gains in maximal and repeated-effort performance alongside training.
Strong Lean mass Reliable increases, partly intracellular water, partly genuine hypertrophy over longer programmes.
Moderate Cognition under sleep loss Short-term memory and reasoning improve in sleep-deprived people and vegetarians, less so in rested omnivores.
Limited Mood & depression Adjunct trials are small and mostly in specific clinical populations.
Dose used in trials
3–5 g

per day, indefinitely. A 20 g/day loading week only shortens time to saturation; it is not required.

Safety
Extensively studied

No kidney harm shown in healthy people across long-term trials. Some report bloating in the first weeks.

Ask a doctor first if
Two cases

Pre-existing kidney disease, or concurrent nephrotoxic medication.

The trials, individually

Open any one for sample size, funding and what it actually measured.

Kreider et al. · position stand · safety
An umbrella review of trials up to five years. Concludes no evidence of renal harm in healthy adults at 3–5 g/day, with performance effects among the most reproducible in the field.
Rae et al. · 45 vegetarians · cognition
Six weeks, crossover, 5 g/day. Working memory and Raven's matrices improved against placebo — an effect largely absent in later trials of meat-eating participants.
Meta-analysis · 22 trials · strength
Pooled gain of roughly 8% in maximal strength over training alone. Effects were larger in untrained participants and in upper-body lifts.

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