DIFFERENCES IN MUSCLE DEVELOPMENT BETWEEN WOMEN AND MEN
- Ferit Celik
- Dec 20, 2025
- 4 min read
Muscle development is a crucial topic in the world of sports; however, we will address the question of whether muscle development progresses more slowly in women than in men. In this article, we will discuss the biological and hormonal reasons for muscle development in women and men. We will also support our findings with an example of a scientific experiment.
🧬 1. Essential Hormones: Testosterone and Estrogen
Men: Testosterone levels are approximately 10–20 times higher than in women.
Testosterone is a hormone that increases muscle protein synthesis and promotes the growth of muscle fibers (especially type II fibers).
Therefore, muscle mass and strength increases are generally faster and more noticeable in men.
Women: They have lower testosterone and higher estrogen levels.
Estrogen does not completely inhibit muscle growth; on the contrary, it supports muscle repair and connective tissue strength .
However, it is not as powerful as the anabolic (muscle-building) effect of testosterone.
💪 2. Muscle Mass and Strength
On average, men have 30–40% more muscle mass (as a percentage of total body weight) than women.
But beware:
Under the same training and nutritional conditions , women can show similar proportional growth to men.
So, while the "potential for growth" differs hormonally, the rate of increase can be similar depending on the stimulus given (e.g., a 10% increase in strength).
⚖️ Result:
Feature | Male | Woman |
Testosterone | High | Low |
Estrogen | Low | High |
muscle mass | More | Less |
Muscle growth rate | Faster | Slower but steady. |
Durability | Middle | Better recovery |
Hypertrophy potential | High | More limited |
🔹 In summary:
Men have an advantage in increasing muscle mass due to the effect of testosterone.
Women can achieve impressive progress in strength and endurance with less hormonal support; they also have some advantages over men in terms of muscle endurance and recovery capacity .
🧬 Muscle fiber types (in both sexes)
Type I (slow-twitch, oxidative)
It is focused on durability.
It contains more mitochondria.
It is effective in sustained effort (e.g., marathon running).
Type IIa (fast-twitch, oxidative-glycolytic)
It strikes a balance between durability and strength.
Type IIx (fast-twitch, glycolytic)
It is effective in short-duration, high-strength activities (e.g., sprinting, weightlifting).
⚧ Differences between men and women
Feature | Men | Women | Explanation |
muscle mass | More (due to the effect of testosterone) | Less | Muscle volume and cross-sectional area differ due to hormonal variations. |
Type I fiber ratio | Generally a little less | Generally a little more | Women generally have a higher proportion of oxidative (endurance-friendly) fiber. |
Type II fiber ratio | Generally more | Generally less | Men have a relatively higher proportion of fast-twitch muscle fibers. |
Muscle strength | Absolutely more | Relatively similar (in proportion to body weight) | Muscle volume, not fiber type distribution, is the determining factor. |
🧠 Summary
The muscle fiber types are the same , but their distribution ratios and fiber diameters differ.
Women have a slight tendency towards endurance, while men have a slight tendency towards strength.
These differences can vary depending on genetics, hormones, type of training, and individual factors.
Genetic Factors
Genetics have a significant influence on muscle development. Some women may be predisposed to slower muscle growth than men. This genetic difference encompasses many components, including the type of muscle fibers, hormone levels, and muscle growth potential. For example, some women may genetically have fewer muscle fibers, which increases the slower muscle development. However, some men may also experience slower muscle growth for the same reasons.
Effects of Training and Nutrition
Muscle building is not only related to hormones and genetics, but also to the training method and nutrition applied. High protein intake supports muscle repair and growth. Since women tend to prefer lower protein intake compared to men, this can affect muscle development. However, implementing a proper resistance training program also plays an important role in muscle development in women. Seeking support from a nutritionist also increases muscle development. There are no significant differences between men and women in terms of the proportions required for nutrition and training, depending on the individual.
Example of a Scientific Experiment
Study
Sex differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta‐analysis (Refalo et al., 2025)
Participants: Healthy men and women aged 18-45 who underwent the same resistance training intervention.PMC+1
The outcome examined: Change in muscle size — both absolute and relative increase compared to baseline.PMC
Results:
A small but significant difference was found in absolute muscle volume increase in favor of men (Standardized mean difference SMD = 0.19; 95% HDI: 0.11-0.28), meaning men showed slightly greater absolute growth.PMC+1
However, no significant difference was found between women and men in relative change from baseline (Exp. %Change of lnRR = 0.69%, 95% HDI: −1.50 to 2.88), meaning women are not significantly "slower" than men in terms of relative change.PMC+1
Regionally: Absolute hypertrophy in the upper body region was slightly greater in men; this difference was not statistically significant for the lower body.PMC
Comment
This study tells us the following:
Women and men do not show significant differences in terms of "how much they have grown compared to their starting point " under the same resistance training.
However, men have a slight advantage over women in terms of absolute volume increase (e.g., muscle area increase measured in mm² or cm³).
This difference likely stems from initial differences in muscle volume and biological variations such as hormone levels. The study doesn't fully explain these mechanisms.
Therefore, instead of saying "women definitely develop muscle slower than men," it's more accurate to say "men may have a slight advantage in absolute volume; however, in terms of proportional growth, women and men are very similar."
In conclusion
There are many scientific reasons why muscle growth is slower in women. Hormonal differences, muscle fiber type distribution, genetic factors, and the effects of training and nutrition are important elements to consider in explaining this. However, even though women have slower muscle mass development, they can achieve significant muscle gains with the right training methods and nutrition plans. Female athletes and coaches should create individualized training programs taking into account hormonal and genetic differences and pay attention to healthy eating habits.
NOTE: The scientific study I shared, conducted in 2025, did not observe significant proportional differences in muscle development between men and women.
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