It is not true that it is more difficult for women to strengthen their muscles

Men have a greater muscle mass than women for a specific reason: from puberty they produce a greater quantity of testosterone, The hormone that stimulates muscle protein synthesis, significantly higher than in women (up to 15 times higher), which promotes increased muscle mass and strength and contributes to greater muscle fiber synthesis. That said, it's absolutely not true that it's harder for women to "build muscle" through physical training than it is for men. This is a widespread fake news story, which has been flatly debunked by a meta-analysis published in February 2025 in the journal Peer J.

The research, entitled “Sex differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta-analysis” (translated into Italian: “Gender differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta-analysis”), analyzed 29 studies on healthy adults (18–45 years), in which men and women followed the same training protocol. The research team involved in the review included scholars from the University of Deakin (Australia), Parker (USA), and Edinburgh (UK). The conclusions are very interesting:

• In absolute terms (e.g. inches of circumference or muscle area), men increase muscle mass slightly more of women. The observed effect, however, is very small.
• In relative terms (i.e. the percentage increase compared to the initial muscle mass), men and women grow at practically the same rate.
• The absolute difference is explained mainly by the fact that men on average start out with a greater muscle mass, not by the fact that female muscles “grow worse”.

The situation changes when physical activity is aimed at weight loss: in this case, women tend to maintain a higher body fat percentage.

This is mainly due to physiology and hormones, not to decreased training effectiveness.

The main reasons are:

• Estrogens: they promote a greater accumulation of subcutaneous fat, especially on the hips, buttocks and thighs.
• Reproductive function: A certain amount of body fat is important for the production of sex hormones, the regularity of the menstrual cycle, and potentially for pregnancy and breastfeeding.
• Differences in body composition: Men have on average more muscle and bone mass, while women have a higher proportion of essential adipose tissue.

For this reason there is also a difference in the so-called essential fat, that is, the fat necessary for the normal functioning of the body:

• Men: about 2-5% of body weight.
• Women: about 10-13%.

This difference is physiological and does not necessarily imply worse health or lower performance: it is simply a biological characteristic of the average body composition of the two sexes.

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