Creatine monohydrate is the most researched ergogenic supplement in sports science. It has been studied in hundreds of randomized controlled trials over several decades. The findings are unusually consistent for a nutrition topic. And despite this, it is surrounded by persistent misconceptions — that it causes kidney damage, that it's only for bodybuilders, that it's a steroid-adjacent shortcut.
None of these are accurate. Here's what the research actually says.
Quick answer
Creatine monohydrate has unusually strong evidence for improving repeated short, high-intensity efforts such as lifting, sprinting, and power training. Standard daily dosing is usually 3-5 grams. For healthy people, recommended-dose creatine has not shown the kidney-damage pattern people often fear, though anyone with kidney disease should treat it as a clinician question.
What creatine is and does
Creatine is a naturally occurring compound produced in the liver, kidneys, and pancreas from amino acids. It's also found in meat and fish. The body stores creatine primarily in muscle as phosphocreatine, where it serves as a rapid energy reservoir for the ATP-PCr system — the energy pathway used for short, high-intensity efforts lasting up to about 10 seconds.
When you sprint, jump, or lift a heavy weight, the phosphocreatine system provides the immediate energy. This system depletes in seconds and then requires time to replenish. Supplementing with creatine increases phosphocreatine stores by 10-40%, which means more fuel available for these high-intensity efforts and faster replenishment between efforts.
What the evidence shows it helps
High-intensity performance. The effect on short, maximal efforts — sprints, heavy resistance training, power output — is well established and clinically meaningful. A meta-analysis of over 150 studies found that creatine supplementation improves maximum power output by about 5-15% compared to placebo in resistance training contexts.
Muscle mass. Creatine increases muscle water content acutely (which is why there's initial weight gain of 1-2kg within the first week — water, not muscle). Over longer supplementation periods, the performance benefits lead to greater training stimulus and more actual muscle protein synthesis. Meta-analyses consistently show greater lean mass gains in creatine users compared to placebo in the context of resistance training.
Cognitive function. More recently, research has examined creatine's effects on the brain, which also uses phosphocreatine. Effects on cognitive performance appear most pronounced under conditions of sleep deprivation or mental fatigue, and in older adults. A 2023 meta-analysis found modest but consistent benefits on memory tasks. This is an active research area.
What it doesn't help
Aerobic endurance. The ATP-PCr system isn't the primary energy pathway for longer efforts. Creatine supplementation shows minimal benefit for distance running, cycling, or other sustained aerobic activities. Some studies find marginal improvements in repeated sprint protocols, but creatine is not a relevant supplement for marathon training.
The kidney damage myth
The concern about creatine and kidney damage is based on a misunderstanding. Creatine metabolism produces creatinine, which is filtered by the kidneys and used clinically as a marker of kidney function. Supplementing creatine raises creatinine levels — which caused early concern that kidney function was impaired.
But elevated creatinine from creatine supplementation is not the same as elevated creatinine from kidney damage. The kidneys aren't being harmed; they're excreting more creatinine because there's more creatine being metabolized. Multiple long-term studies in healthy individuals have found no adverse effects on kidney function from creatine supplementation at recommended doses.
People with existing kidney disease should consult a physician. For healthy people, decades of research have not found evidence of harm.
Dosing
Creatine monohydrate is the best-studied and cheapest form. Newer forms (creatine HCl, buffered creatine, etc.) have not been shown to be more effective in direct comparison trials.
Standard dosing: 3-5 grams daily. Loading protocols (20g/day for 5-7 days) reach saturation faster but produce the same endpoint as consistent lower dosing after 3-4 weeks. Timing relative to exercise shows minimal difference in research, though post-workout consumption shows a slight edge in some studies.
It is one of the few supplements where the evidence is strong enough that "should probably take it if you do resistance training" is a defensible statement.
For comparison with more conditional supplement claims, read vitamin D evidence and magnesium supplements.