Creatine
The most evidence-backed supplement for strength and power output
Plain English
Creatine is a compound made from amino acids that your body stores in muscle as phosphocreatine. During short, intense efforts, phosphocreatine donates a phosphate group to replenish adenosine triphosphate (ATP), the molecule your muscles burn for energy. Supplementing with creatine raises muscle phosphocreatine stores above what diet alone can provide, extending your capacity for high-intensity work.
The Mechanism
Your muscles run on ATP (adenosine triphosphate), but they can only store a few seconds' worth at any given moment. During a hard sprint or a maximal lift, ATP is depleted in 1 to 3 seconds. Phosphocreatine steps in immediately, donating a phosphate group to ADP (adenosine diphosphate) to regenerate ATP. This phosphocreatine-ATP system sustains maximal intensity for roughly 8 to 12 seconds before other energy systems must take over.
Creatine stores in muscle are partially limited by dietary intake. Most people carry muscle creatine at roughly 60 to 80% of maximum capacity, leaving meaningful headroom. Supplementing with creatine monohydrate, the most studied form, raises intramuscular phosphocreatine stores by 20 to 40% in most people, according to research by Harris, Soderlund, and Hultman published in the 1990s. This expanded reserve allows more total work to be completed before the phosphocreatine system is exhausted: more reps at a given weight, faster recovery between maximal efforts, and a higher ceiling for explosive output.
Creatine also draws water into muscle cells, which has downstream effects on protein synthesis signaling and cell hydration. There is emerging evidence for cognitive benefits, particularly under sleep deprivation or high mental demand, though the mechanisms are less established than the muscular performance effects. The cognitive benefit may reflect the same ATP-resynthesis role: brain tissue has high ATP demand and limited phosphocreatine buffering capacity.
Why It Matters
Creatine does not build muscle directly. It allows more total training work to accumulate, and training builds the muscle.
Multiple meta-analyses show an average 5 to 15% improvement in maximal strength and power output with creatine supplementation. For compound lifts, this often translates to 1 to 2 additional reps per set at the same load, compressing the timeline for progressive overload. Over a 12-week training block, the additional accumulated work volume is meaningful. Creatine also has evidence in older adults, vegetarians (who have lower baseline muscle creatine from reduced dietary intake), and cognitively demanding contexts.
Common Misconception
Creatine is often assumed to be a steroid or a compound that works by directly building muscle. It does neither. It does not stimulate anabolic hormones directly; it extends the duration of high-intensity work, allowing more training volume to accumulate. The concern about kidney damage is not supported by evidence in healthy adults; decades of research at doses up to 5g per day show no adverse effects on renal function in people without pre-existing kidney disease.
How to Improve It
3 Things to Remember
Creatine extends the phosphocreatine-ATP system that powers maximal effort: more phosphocreatine means more total work before fatigue, not a direct anabolic hormone signal.
Supplementing with 3 to 5g of creatine monohydrate daily raises intramuscular stores by 20 to 40%, translating to an average 5 to 15% improvement in maximal strength and power across multiple meta-analyses.
Creatine monohydrate is the evidence-backed form; it is safe in healthy adults at standard doses, requires no loading phase, and reaches near-saturation within 3 to 4 weeks of daily use.
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