Study
Influence of age, sex, and type of exercise on the efficacy of creatine supplementation on lean body mass: A systematic review and meta-analysis of randomized clinical trials
Across 35 RCTs and 1,192 participants, creatine raised lean body mass by 0.68 kg overall (95% CI 0.26 to 1.11) and by 1.10 kg when combined with resistance training (95% CI 0.56 to 1.65), but by 0.03 kg without exercise.
Summary Does creatine help people gain lean body mass? Show / hide ↓
Researchers combined results from 35 randomized trials, where people were assigned by chance to take creatine or a comparison treatment. The trials included 1,192 adults and measured lean body mass, meaning body weight that is not fat, including muscle and water. Overall, creatine added about 0.68 kilograms of lean body mass. The gain was about 1.10 kilograms with resistance training, such as lifting weights, but almost zero without exercise; results were also clearer in men than women.
What this means for you: Creatine may add roughly 1 kilogram of lean body mass when paired with resistance training, but it is not a substitute for training. The measurement can include extra water as well as muscle, and the evidence was less clear for women and for people who did not exercise.
moderate evidenceFelipe Delpino and colleagues searched PubMed, SPORTDiscus, Web of Science and Scopus to May 2022 and pooled 35 RCTs covering 1,192 participants. Animal studies and disease-specific populations were excluded. The outcome was lean body mass. Subgroup analyses split results by age, sex and exercise type. The protocol was registered as PROSPERO CRD42020207122.
Overall, creatine increased lean body mass by 0.68 kg (95% CI 0.26 to 1.11). Exercise type decided the size of the effect. With resistance training the gain was 1.10 kg (95% CI 0.56 to 1.65) and held across ages. With mixed exercise the gain was 0.74 kg but the interval spanned zero (95% CI -3.89 to 5.36). Without any exercise the gain was 0.03 kg (95% CI -0.65 to 0.70), which is nothing.
Sex mattered too. Males gained 1.46 kg (95% CI 0.47 to 2.46). Females gained 0.29 kg (95% CI -0.43 to 1.01), which was not statistically significant. This is the clearest quantitative statement of the core creatine claim: about 1 kg of extra lean mass, and only alongside resistance training.
In conclusion, the addition of creatine supplementation to a resistance training program increases LBM.
Lean body mass is not the same as contractile muscle. Creatine draws water into muscle cells, and this meta-analysis cannot separate intracellular water from myofibrillar protein, so part of the 1.10 kg is likely fluid. The abstract does not report doses, durations or heterogeneity statistics, so the pooled estimate cannot be tied to a specific protocol. The mixed-exercise subgroup interval was extremely wide (-3.89 to 5.36 kg), signalling very few or very inconsistent trials. The female estimate was null, and the authors do not resolve whether that reflects a real sex difference or fewer female participants. Scott Forbes and Darren Candow are frequent creatine authors with industry ties reported in other papers. Trials in people with specific diseases were excluded, so the result applies to generally healthy participants only.
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