Creatine Boosts Men's Strength. For Women, the Data Is Weaker.

Creatine is the most studied supplement in sports nutrition, and the largest meta-analysis ever conducted on it just revealed a gap nobody in the supplement industry wants to talk about: the strength benefits are significant for men and non-significant for women.

The Short Answer

Creatine reliably improves strength and lean body mass in men. For women, three separate analyses found minimal or non-significant strength gains. This is likely an evidence gap rather than proof creatine does not work for women. Only 3 of 27 female-specific studies even controlled for menstrual cycle, which influences creatine metabolism.

69 Trials, 1,937 People, One Clear Split

The Kazeminasab et al. 2025 meta-analysis in Nutrients pooled 69 randomized controlled trials with 1,937 total participants. Overall, creatine plus resistance training produced significant improvements: +5.64 kg on squat (p=0.001), +1.43 kg on bench press (p=0.002), +1.48 cm on vertical jump (p=0.01), and +47.81 W on Wingate peak power (p=0.004).

Then they split the data by sex.

Males: squat improved by +6.43 kg (p=0.001), leg press by +9.79 kg (p=0.001), vertical jump by +1.52 cm (p=0.04), Wingate power by +55.31 W (p=0.001). Every metric reached statistical significance.

Females: squat improved by +1.63 kg (p=0.44), leg press by +2.53 kg (p=0.57), vertical jump by +0.61 cm (p=0.60), Wingate power changed by -5.79 W (p=0.61). Not a single metric reached significance. The power output actually trended slightly negative.

The gap is not subtle. Males gained nearly four times the squat strength from creatine supplementation. The female results were not just smaller. They were statistically indistinguishable from placebo.

The Female-Only Research Tells the Same Story

Tam, Mitchell, and Forsyth reviewed 27 studies examining creatine in active females specifically, published in Nutrients in 2025. The findings were similarly underwhelming. Only 3 of 11 studies showed strength or power improvements compared to placebo. Only 4 of 17 studies showed anaerobic performance benefits. Only 1 of 5 studies showed aerobic performance improvements.

But the most revealing number from this review is not a performance metric. It is methodological: only 3 of 27 studies classified participants by menstrual cycle status. Hormonal fluctuations influence creatine metabolism, and almost no studies controlled for that variable. The female evidence base is not just smaller. It is systematically weaker in design.

The Lean Mass Data Points the Same Direction

Delpino and colleagues pooled 35 RCTs with 1,192 participants in a 2022 meta-analysis in the journal Nutrition. They found creatine plus resistance training increased lean body mass by approximately 1.1 kg across all ages, with high credibility of evidence. When they stratified by sex, males showed greater lean body mass gains than females.

This is a different outcome from the Kazeminasab strength data (lean mass vs. maximal strength), but the direction is the same. Three independent research groups, three different outcome measures, three analyses all converging: creatine produces clearer benefits in men than in women.

This Is an Evidence Gap, Not a Verdict

The non-significant female results could mean creatine genuinely does not improve strength in women. Or it could mean the studies testing creatine in women are too few, too small, and too poorly designed to detect an effect that actually exists.

The Kazeminasab meta-analysis had substantially fewer female-inclusive RCTs than male studies, reducing statistical power. If you run an underpowered analysis, you get non-significant results even when the effect is real. But three independent analyses all finding weak female results makes the "just underpowered" explanation harder to sustain. If the null findings were purely a sample size issue, at least one of the three should have found significant female benefits by chance.

The honest answer: we do not know. The sex difference is consistent across every available analysis, and the methodological quality of the female evidence base (24 of 27 studies ignoring menstrual cycle) makes the entire dataset suspect. No large RCT has been designed specifically to test creatine's strength effects in women with proper menstrual cycle classification and adequate sample size. Until that study exists, the question stays open.

What to Actually Do With This Information

If you are a man, creatine's strength benefits are well-established. 3-5 grams per day. The evidence supports it clearly.

If you are a woman, the strength evidence is inconclusive, not negative. Creatine is inexpensive, has an excellent safety profile across decades of research, and has no documented downside. The decision is a personal cost-benefit assessment: a few dollars a month for a supplement that might help and almost certainly will not hurt, or skipping it until better female-specific research exists.

Creatine may also have benefits beyond strength that these analyses did not capture: cognitive function, bone mineral density, and exercise recovery. Those are separate evidence questions with their own literature.

Do not let supplement marketing tell you the science is settled for women. It is not. And do not let the current gaps in the evidence tell you creatine is useless for women. That conclusion is not supported either.

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