Creatine

What is it?

Creatine is a compound your body makes and also gets from foods such as meat and fish. Most of it is stored in muscle. Creatine monohydrate is the form used in most studies and the straightforward choice for a supplement. [1]

How does it work?

Muscle stores some creatine as phosphocreatine, which helps rapidly restore ATP—the energy your muscles use to contract. That matters most during short, hard efforts and repeated sets. Creatine also has an energy role in the brain, but a plausible mechanism does not guarantee a noticeable cognitive benefit. [1,7]

Why use it?

Building muscle and strength

Creatine can help you get more out of resistance training. Across 23 randomized trials in adults under 50, people taking creatine gained more maximal strength than placebo groups doing resistance training: about 4.4 kg more on upper-body measures and 11.4 kg more on lower-body measures, on average. Those are study averages, not a promise for any one lifter. [3]

For actual muscle size, a review of 10 training studies using muscle imaging found a small added benefit with creatine. The size benefit appears smaller and less certain than the strength benefit. Early scale or “lean mass” gains can also include water held in muscle, rather than being all new muscle tissue. [2]

Muscular endurance and repeated efforts

Creatine is most useful when “endurance” means sustaining output across hard sets or sprints. In one small, double-blind study of trained handball players, five days of creatine improved repetitions to fatigue and repeated-sprint performance versus placebo. That result supports its use for repeated high-intensity work, but it does not establish the same size of benefit for every exercise or athlete. [4]

Aerobic endurance

For steady running or cycling, the case is much weaker. The handball study found no improvement in endurance running, and a review of 19 randomized trials did not find improved VO2max, a measure of aerobic capacity. Creatine is therefore not a reliable supplement for increasing steady-state endurance. VO2max alone does not answer every race-performance question. [4,5]

Cognitive benefits and sleep loss

Creatine may help some mental tasks, but the evidence is less settled than it is for training. A 2024 review of 16 trials found signals for memory and a few timed tasks, but no clear improvement in overall cognition or executive function. A separate European Food Safety Authority review found that a reliable general cognitive benefit had not been established. [6,7]

The picture is more promising during severe sleep deprivation. In two small, double-blind crossover studies, participants stayed awake for about 21 hours. A 2024 study of 15 adults tested one dose of 0.35 g/kg (about 25 g for a 70 kg person); a 2026 follow-up of 29 adults tested 0.2 g/kg (about 14 g at 70 kg). Compared with placebo, creatine reduced deterioration on some memory, reasoning, or processing-speed tasks. The studies came from the same research group, and not every result in the newer trial held up after accounting for the many tests performed. [8,9]

Daily high-dose evidence is mixed. A 2025 study of 14 active men found that 20 g/day for seven days improved one attention test and subjective sleep quality, without improving measured sleep duration or efficiency. A different study found no cognitive advantage from either 10 or 20 g/day for six weeks in 30 healthy young adults. These studies measured test performance and sleep, not treatment of a mental-health condition. They do not establish that taking 10–20 g every day will offset an ordinary short night of sleep. [10,11]