Creatine monohydrate is the most thoroughly researched compound in sports nutrition. It has been studied for over three decades, across thousands of participants, in well-designed randomised controlled trials. The evidence for its primary effects on strength and power output is strong enough that it sits in a different category from almost all other sports supplements.

What creatine does and why

Creatine is a naturally occurring compound synthesised in the liver, kidneys, and pancreas from the amino acids arginine and glycine. Most of the body's creatine is stored in skeletal muscle as phosphocreatine (PCr).

During high-intensity exercise — a heavy lift, a sprint, an explosive movement — the body needs ATP (adenosine triphosphate) faster than aerobic metabolism can supply it. Phosphocreatine resynthesises ATP extremely rapidly, at a rate roughly 12 times faster than oxidative phosphorylation. This short-duration energy system is what powers explosive efforts lasting up to about 10 seconds.

Supplementing with creatine monohydrate increases intramuscular phosphocreatine stores by roughly 20–40%, extending the duration and intensity at which this system can operate before fatigue sets in. The practical effect is that you can complete more work at high intensity before the rapid energy system is depleted — more reps, heavier loads, more power output.

Over time, this increased training capacity translates to greater training-induced adaptations: more strength, more muscle.

The performance evidence

Multiple meta-analyses confirm that creatine supplementation produces meaningful improvements in strength and power output during short-duration, high-intensity exercise. Effects are consistently seen across resistance training, sprint performance, and high-intensity interval protocols.

Effect sizes vary — roughly 5–15% improvement in strength outcomes in most studies — which is modest in absolute terms but practically significant for training context.

The effects are well-established enough that the International Society of Sports Nutrition (ISSN) classifies creatine monohydrate as the most effective ergogenic nutritional supplement currently available for athletes seeking to increase high-intensity exercise capacity and lean body mass.

Cognitive evidence

Creatine also crosses the blood-brain barrier and supports ATP resynthesis in brain cells. Recent meta-analyses report that creatine supplementation significantly improves memory performance, with moderate certainty of evidence. Effects appear strongest in populations with naturally lower creatine stores — vegetarians and vegans (who consume no dietary creatine from meat), and older adults. The cognitive evidence is promising but at an earlier stage than the performance evidence.

Who benefits most

Creatine's benefits are largest in populations with lower dietary creatine intake, because the supplementation gap is larger:

  • Vegetarians and vegans: dietary creatine comes entirely from animal products; supplementation provides all of the creatine their muscles would otherwise synthesise from scratch
  • Older adults: natural creatine stores decline with age; supplementation may support muscle preservation and cognitive function
  • People performing high-intensity training: the evidence is built on this population, and they are the ones whose training demand is most supported by increased PCr stores

How to take it

A maintenance dose of 3–5g of creatine monohydrate per day is the standard recommendation, taken consistently. There is no requirement for a loading phase (20g/day for 5–7 days) — loading reaches saturation faster but the same endpoint is reached within 3–4 weeks at maintenance dose. Take it whenever is convenient; timing doesn't significantly affect outcomes.

Creatine monohydrate is the only form worth using. Other forms (creatine HCl, buffered creatine) offer no demonstrated advantages and are substantially more expensive.