On the physiological half of the claim, the strongest evidence does not say women fail to build muscle. It says women build muscle at a similar relative rate to men, from a smaller starting point. The Roberts, Nuckols and Krieger meta-analysis found that the analysis of hypertrophy comprised 12 outcomes from 10 studies with no significant difference between males and females (effect size 0.07 ± 0.06; P = 0.31) . A 2025 Bayesian meta-analysis found that absolute increases in muscle size slightly favoured males, while relative increases in muscle size were similar between sexes, with absolute hypertrophy of upper body but not lower body regions favoured in males , and the authors concluded that the findings strengthen the understanding that females have a similar potential to induce muscle hypertrophy .

What limits visible "bulk" in practice is the absolute magnitude of change, not an inability to grow muscle. In a 12 week moderate intensity progressive weight training program in 20 previously untrained women aged 19 to 44, fat free mass rose from 44.2 ± 5.4 kg to 46.2 ± 6.0 kg , roughly 2 kg over three months. A meta-analysis of resistance training in postmenopausal and elderly women observed a mean increase of 4.8% in lean body mass and a mean decrease of 2.1% in fat mass across the retrieved studies . A large meta-analysis of 114 trials in people with overweight or obesity found resistance training alone was the most effective intervention for increasing lean mass compared with no training controls (0.8 kg, 95% CI 0.6 to 1.0 kg).

The health and fitness benefits referenced in the caption are supported. WHO guidelines state there is moderate certainty evidence that muscle strengthening activities undertaken on 2 or more days a week provide additional health benefits . A 2025 meta-analysis of 17 randomised controlled trials involving 690 postmenopausal women found resistance training significantly improved bone mineral density at the lumbar spine, and an earlier meta-analysis concluded resistance training had a positive effect on bone mineral density at the lumbar spine in all women and at the femur and radius in postmenopausal women .

On the aesthetic half of the claim, there is no scientific finding that strength training makes women "more beautiful." Research on how muscularity is perceived is mixed and does not support a universal statement. One study reported that women with the lowest level of muscularity received the highest ratings of physical attractiveness, followed by moderate and then high levels, and that heavily muscled female physiques tended to be perceived as having more stereotypically masculine traits . A separate study using schematic figures found the opposite direction in one condition: overweight and underweight figures were rated as less healthy and attractive, but overweight figures with high levels of muscularity were rated more highly than less muscular figures . Attractiveness is a rater dependent social judgment, not a physiological outcome.