Creatine adds muscle, but far less than the hype

Creatine is one of the most widely used sports supplements, and it is routinely promoted as a way to build extra muscle when combined with lifting. Much of the debate, however, hinges on how muscle growth is measured, and direct imaging of specific muscle sites is a far more demanding test than whole-body estimates. Whether creatine genuinely enlarges individual muscles when tracked with scans is therefore a sharper question than whether it shifts lean mass on a scale. This review set out to pool every randomised trial that put that question to the test.

The authors ran a systematic review with meta-analysis of randomised controlled trials lasting at least 6 weeks in healthy adults. Eligible trials combined creatine supplementation with resistance training and measured site-specific hypertrophy directly using magnetic resonance imaging, computed tomography or ultrasound, against resistance training with a placebo. In total, 44 outcomes across 10 studies met the inclusion criteria. The team performed univariate and multivariate analyses on the standardised outcomes and used regression to examine whether covariates, such as participant age, moderated the effect.

The pooled estimate across all standardised outcomes was 0.11, with a 95% credible interval from -0.02 to 0.25 — evidence for a very small effect favouring creatine when combined with resistance training. Multivariate analyses found similarly small benefits for changes in upper- and lower-body muscle thickness, in the range of 0.10-0.16 cm. Moderator analysis suggested a small superior benefit in younger compared with older adults (0.17, credible interval -0.09 to 0.45), though that interval also spans zero. Nothing in the data pointed to a large hypertrophy advantage from supplementation.

The result is consistent with the broader picture of creatine as a genuinely useful but modest aid, and it sharpens that picture by relying on direct imaging rather than whole-body proxies. It complicates marketing narratives that present creatine as transformative for muscle size. Because the credible intervals cross zero, some uncertainty remains about the average effect's magnitude. Open questions include whether age, training status or dosing strategy meaningfully changes the response, since the moderator analyses were imprecise. Several authors also declared industry relationships, which readers may wish to weigh.

If you already take creatine while lifting, the fairest reading is that it may add a small amount of measurable muscle on top of what training alone delivers, in both the upper and lower body. The training itself remains the overwhelming driver of growth; supplementation appears to fine-tune the outcome rather than transform it. This is a reason to hold realistic expectations of any supplement. 'Statistically detectable' and 'visibly dramatic' are very different things, and this evidence sits firmly in the first category.