Benefits
Strength and power output
In a meta-analysis of 60 placebo-controlled trials, creatine monohydrate improved lower-body strength in efforts under 3 minutes, such as squat and leg press (effect size 0.24). A second meta-analysis of 53 trials found a similar gain in upper-body strength such as bench press (0.32). The gains were small to moderate and did not depend on age, sex or activity level.
Lean mass gains alongside training
Reviews of the trials conclude that creatine taken during heavy resistance training increases fat-free mass and muscle size more than training alone. Part of the early gain is water held inside muscle cells; part appears to come from the extra training volume creatine allows. It does not build muscle without training.
High-intensity exercise capacity
Creatine helps most in short, repeated maximal efforts such as sprints, jumps and lifting sets, where phosphocreatine is rebuilt between bouts. Reviews note that the benefit shrinks as exercise gets longer, so effects on steady endurance events are smaller and less consistent.
Memory and cognitive performance
Studies show mixed results for memory. One meta-analysis of 16 trials found a small memory gain but no clear effect on overall cognition; another found the clearest effect in adults aged 66 to 76. The largest single trial, in 123 adults taking 5 g a day for 6 weeks, found no significant gain. Reviewing an AlzChem application, the European Food Safety Authority concluded in 2024 that a cognitive benefit has not been established.
Muscle recovery after immobilization
In a double-blind trial in 22 young adults whose leg was in a cast for 2 weeks, those taking creatine (20 g a day tapering to 5 g) regained thigh muscle size and knee-extension power faster during 10 weeks of rehabilitation training than those on placebo. Creatine did not prevent the loss during the cast period itself.
Mechanism of action
Phosphocreatine energy buffering
Muscle stores creatine mostly as phosphocreatine, which quickly hands a phosphate group to ADP to rebuild ATP during intense work. A typical diet leaves muscle stores about 60 to 80% full, and supplementation raises muscle creatine and phosphocreatine by about 20 to 40%.
Water drawn into muscle cells
Creatine pulls water into muscle cells as it is stored. Early studies of loading found about 0.5 to 1 liter of extra body water, which matches most of the quick weight gain in the first week.
Brain creatine
The brain also uses the creatine kinase system to buffer energy. Supplementation raises brain creatine by roughly 5 to 15%, which is the proposed reason for effects on memory and mental fatigue, especially in people who eat little creatine.
Myogenic signaling during retraining
In the immobilization trial, creatine increased the muscle growth factor MRF4 during rehabilitation, and the rise tracked the increase in muscle fiber size. This is one proposed route to the larger training gains.
Clinical trials
Systematic review and meta-analysis of randomized placebo-controlled trials measuring lower-limb strength in efforts under 3 minutes (Lanhers et al. 2015, Sports Med)
60 studies: 646 people taking creatine and 651 controls.
Creatine improved squat (effect size 0.34) and leg press (0.30) strength; the overall lower-limb effect was 0.24. Meta-regression found no link with age, sex, activity level or dosing.
Systematic review and meta-analysis of randomized placebo-controlled trials measuring upper-limb strength in efforts under 3 minutes (Lanhers et al. 2017, Sports Med)
53 studies: 563 people taking creatine and 575 controls.
Creatine improved bench press (effect size 0.27) and chest press (0.68); the overall upper-limb effect was 0.32. Results did not differ by population or supplementation characteristics.
Double-blind placebo-controlled trial: 2 weeks with the leg in a cast, then 10 weeks of knee-extension rehabilitation training with creatine (20 g a day tapering to 5 g) or placebo (Hespel et al. 2001, J Physiol)
22 young healthy volunteers.
The cast reduced thigh muscle area by about 10% and power by about 25% in both groups. During rehabilitation, muscle area and power recovered faster with creatine. MRF4 protein rose with creatine, and its change correlated with fiber size.
Double-blind placebo-controlled crossover trial of 5 g a day creatine monohydrate for 6 weeks (Rae et al. 2003, Proc Biol Sci)
45 young adult vegetarians.
Creatine improved backward digit span (working memory) and Raven's matrices (reasoning) scores compared with placebo. Vegetarians eat little creatine, so results may not carry over to meat eaters. A larger 2023 replication did not find a significant effect.
Preregistered double-blind placebo-controlled crossover trial of 5 g a day of creatine for 6 weeks (Sandkühler et al. 2023, BMC Med)
123 adults, about half vegetarian and half meat eaters.
Creatine did not significantly improve backward digit span (p = 0.064) or Raven's matrices scores, or any of eight exploratory cognitive tests, and vegetarians did not benefit more than meat eaters. A Bayesian analysis suggested at most a small benefit. Side effects were reported about four times as often with creatine as with placebo.
Systematic review and meta-analysis of randomized trials of creatine monohydrate and cognitive function (Xu et al. 2024, Front Nutr)
16 trials, 492 adults aged about 21 to 76, healthy people and patients.
Creatine improved memory (SMD 0.31, moderate-certainty evidence), attention time and processing speed, but not overall cognitive function or executive function. Evidence outside memory was low certainty.
Position stand review of creatine safety and efficacy in exercise, sport and medicine (Kreider et al. 2017, J Int Soc Sports Nutr)
Review of athletic, aging and clinical studies.
Concludes that creatine monohydrate is the most effective nutritional supplement available for increasing high-intensity exercise capacity and lean body mass during training, and that doses up to 30 g a day for 5 years have been well tolerated in healthy people. The lead author reported industry-funded creatine research.
Expert review of 12 common questions on creatine efficacy and safety (Antonio et al. 2021, J Int Soc Sports Nutr)
Review of over 500 published creatine studies.
Found no evidence that creatine damages healthy kidneys or causes dehydration or cramping, concluded that loading is not required (3 to 5 g a day works), and found that other forms have not been shown to beat monohydrate. Several authors sit on AlzChem's scientific advisory board.