What it is
Regulatory status: OTC dietary supplement (US); food supplement (EU). Not a prescription drug. Not WADA-prohibited
Mechanism evidence: human
At a glance
What it is, why people use it, the evidence, and what to know before trying it.
Why people use it
- Strength and high-intensity / power performance (1RM, repeated sprints, Wingate, work ≤30 s).
- Lean / fat-free mass gain during resistance training.
- Cognitive and brain function in healthy people, including under sleep deprivation and in older adults.
- Faster recovery from hard training (force restoration, less enzyme efflux / inflammation, glycogen).
- Bone mineral density and bone geometry.
- Glucose control / metabolic outcomes (HbA1c, GLUT4, meal tolerance).
- Depression (as SSRI adjunct or standalone).
- Larger response in vegetarians / vegans (low baseline muscle creatine).
- Loading (20 g/day) versus daily low dose (3–5 g/day) as equivalent saturation strategies.
- Safety: that creatine does not harm kidneys in healthy people (the “kidney myth”).
Evidence at a glance
Creatine monohydrate is one of the few supplements whose **muscle** claims survive contact with meta-analyses: it saturates the phosphocreatine pool by ~20%, adds roughly 1.3–1.4 kg extra lean tissue on top of resistance training in older-adult metas, and produces small-to-moderate extra 1RM and high-intensity performance (on the order of +1.4 kg bench and +5.6 kg squat in the 2025 strength meta; 10–20% on repeated anaerobic work in the ISSN synthesis). Loading 20 g/day for 5–7 days and taking 3–5 g/day for a month reach the same muscle ceiling; the first is faster. In healthy kidneys, gold-standard GFR does not fall; the creatinine bump is an artefact. Vegetarians start lower and gain more muscle creatine, lean mass and work capacity in the one biopsy RCT that tested that question.