The goal of strength training is to build strength and muscle size, or at least reduce the loss of muscle mass due to aging. However, a growing number of women want to greatly boost the size of their muscles and are successful at doing so. The question is whether they’re doing it naturally! Some women, like men, take growth-enhancing hormones or supplements, mostly at the professional level. So, you might wonder what the limitations of muscle hypertrophy are for women. How much muscle can a woman develop naturally?
How much muscle a person, male or female, can develop is determined by a complex blend of training and genetic factors. Some women and men have a greater genetic potential to build muscle than others. Often, easy muscle hypertrophy gainers have a mesomorphic frame, meaning they carry a larger amount of muscle on their frame even without training and they have more muscle fibers. With proper training, they can become quite muscular. However, anyone with effort and training can develop some muscle and improve their body composition.
It’s not surprising that genetics are a factor in muscle hypertrophy gains. The DNA your parents hand you influences the composition of your muscle fibers, whether you have more fast-twitch or slow-twitch fibers. Genes also influence hormonal factors that impact muscle growth and the structure of your physique, whether you’re a mesomorph, ectomorph, or endomorph. But training is the stimulus that promotes muscle growth. Even the most genetically gifted mesomorph won’t become lean and ripped without training.
Does Testosterone Make a Difference in Developing Muscle Hypertrophy?
At first glance, it seems that men have the capacity to gain more muscle and gain that muscle faster. You might point to the higher levels of testosterone in men as the reason. It’s true that men have ten times the amount of testosterone as a woman, but the lack of testosterone doesn’t seriously stifle muscle hypertrophy in women. The reason?
Women produce enough growth hormone and IGF-1, another growth factor, to partially compensate for lower testosterone. These hormones have a similar anabolic effect as testosterone. In fact, according to a study in the Journal of Clinical Endocrinology and Metabolism, women produce three times the IGF-1 that men do. Despite lower levels of testosterone, women have the capacity to build muscle and higher levels of IGF-1 may partially explain this.
Despite the capacity of men and women to build muscle size, the rate of muscle hypertrophy growth in women is slower. Men gain, on average, around 1.0 kilogram of muscle per month while women average around 0.5 kilograms per month with similar training. Some research suggests that differences in testosterone may play a role in the slower rate at which women develop muscle. That’s why if you’re a female and want to gain substantial muscle, make sure you use progressive overload and vary the stimulus on your muscles to avoid plateaus.
Also, women sometimes have a harder time building muscle because they calorie restrict to lose body fat. It’s hard to build muscle in a calorie depleted state. As you might guess, protein is important for jumpstarting muscle protein synthesis, especially the amino acid leucine. Studies show that leucine, a branched-chain amino acid, activates the mTOR pathway for muscle hypertrophy.
How Much Muscle Hypertrophy Can You Gain Over Time?
The amount of muscle hypertrophy a person can build over time depends on genetics, type, and consistency of training, nutrition, and body composition. Studies show that people who are taller and have a larger frame can gain more muscle, in general, relative to those who are short and have smaller bones and a smaller frame. Muscle insertion is a factor too. For example, people who have long calf muscles and a short Achilles tendon can develop larger calves than someone with short calf muscles and long tendons. Also, you can develop more pronounced biceps if your biceps have a higher insertion point. These are factors you can’t control.
Women also usually look less muscular than men because they carry more body fat and the fat covers the muscle. For example, a woman usually won’t have visible abdominal definition until they’re below a 20% body fat percentage. You may have developed the underlying muscle, but it isn’t showing due to a layer of fat. Men, having a lower body fat percentage, don’t have this disadvantage.
What about Strength Gains?
In terms of strength gains, studies show that men and women respond similarly to resistance training. In one study, college-aged men and women who did upper body resistance training for 10 weeks enjoyed similar gains in elbow flexor strength. Despite references to females being the weaker sex, research shows that females have similar strength as males when you consider differences in muscle mass. Despite differences in hormonal structure, men and women can both build muscle size and strength. According to the American Council on Exercise, the average woman can improve strength by 30% after weight training for several months.
Train for Muscle Growth
As you can see, women respond similarly to resistance training as men and can boost strength and muscle size. However, women gain muscle size at a slower rate than men. For most women, getting big and bulky isn’t an issue due to hormonal differences. However, polycystic ovary disease is a common problem in women and women who have it have higher levels of testosterone. Therefore, women with this condition may build muscle faster and experience more muscle growth.
If you’re not making gains as quickly as you’d like, look closely at your training. Make sure you’re using progressive overload. Otherwise, your muscles will adapt and stop growing. Keep a food journal for a few weeks to make sure you’re getting enough total calories and protein. Just as importantly, be patient! It takes time for muscles to grow.
- American Council on Exercise. “Building Muscle for Women”
- Curr Opin Clin Nutr Metab Care. 2008 May; 11(3): 222–226. doi: 10.1097/MCO.0b013e3282fa17fb
- com. “Comparison of upper body strength gains between men and women after 10 weeks of resistance training”
- J Clin Endocrinol Metab. 2000 Mar;85(3):1121-5.
- Medical News Today. “How long does it take to build muscle with exercise?”
- Eur J Appl Physiol Occup Physiol. 1993;66(3):254-62.
- com. “Is There A Limit To The Size Of Our Muscles?”