Creatine's body composition effect is real but small

Creatine is one of the most studied supplements in sport, with robust evidence that it benefits body composition, primarily when combined with resistance training. What has been missing is a comprehensive evaluation of how the details of a creatine protocol, including the dose and the form used, influence body mass and estimates of fat-free and fat mass. With hundreds of trials now published, it is possible to size the effect honestly and ask which protocol choices actually matter. That is what this review set out to do.

The authors searched PubMed, Web of Science and Scopus up to July 2023 for randomised controlled trials evaluating creatine supplementation's effect on body composition. From 4831 initial records, 143 studies met the inclusion criteria. Data were pooled using random effect models chosen on the basis of heterogeneity testing, and expressed as weighted mean differences for body mass, fat-free mass and body fat percentage. The analysis also examined whether protocol features, such as including a maintenance dose or combining supplementation with resistance training, changed the results.

Creatine supplementation increased body mass by 0.86 kg and fat-free mass by 0.82 kg, and reduced body fat percentage by 0.28 percentage points. The consistency across studies was striking, with essentially no disagreement between trials on any of the three outcomes. Studies that incorporated a maintenance dose of creatine, or that performed resistance training alongside supplementation, showed greater effects on body composition. The authors' overall verdict is that the effect on body mass and estimates of fat-free mass and fat percentage is small, and more robust when combined with resistance training.

This confirms the long-standing picture that creatine works, while putting an honest number on how much: the average lean mass gain is under a kilogram. It extends previous work by showing that protocol details matter, with maintenance dosing and concurrent resistance training amplifying the effect. The finding cuts both ways for readers: creatine is among the most reliable supplements available, yet its standalone contribution is modest. It leaves open exactly how different forms and dosing strategies compare head to head.

This is a reason to see creatine as dependable but not transformative: across a very large body of randomised evidence, it adds a small amount of lean mass and trims body fat percentage slightly. The pattern that effects were bigger with resistance training suggests the supplement works best as a companion to training rather than a substitute for it. Anyone expecting dramatic changes from the powder alone is likely to be disappointed by the averages here. As ever with supplement research, note that one author reports industry links, though the review pooled independent trials.