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Your Guide to Female Hormones and the Muscular Potential of Women

The science of bulking up.

It’s a fact, men naturally have more muscle than women. However, this doesn’t mean that the muscular potential of women is dire.

Even if women have a propensity to gain more fat cells than men as they carry children – the extra fat is there to help protect the growing foetus – there are a number of hormones that women produce that have an effect on their muscular potential.

It’s not all about testosterone.

Hormones control the size of your muscles, telling your body to break them down or grow them bigger. To understand the science behind the hormones that can help you bulk up, we’ve explained more about what they do and the role they play in building muscle.

Read more: How the Oral Contraceptive Pill Affects Performance

female athlete stretches before sportSource: RODNAE Productions on Pexels

Important hormones for building muscle

Growth Hormone And IGF-1

Growth hormone is produced in the pituitary gland. It stimulates the liver so that it produces IGF-1, the hormone that’s ultimately responsible for anabolic muscle growth. The production of growth hormone declines with age. This hormone has an inverse relationship to body fat. This means that the less GH and IGF-1 that you produce, the more body fat you will amass.


Insulin is the storage hormone that’s produced by the pancreas in response to food. When we eat, food gets broken down into glucose, fatty acids, amino acids, vitamins and minerals. Insulin warehouses the stored form of glucose, which is known as glycogen, in muscles and the liver. It also enables amino acids to repair damaged tissues and also build muscle mass.

These effects are considered to be anabolic.

The production of insulin is mainly influenced by exercise and diet. The consumption of carbohydrates and protein plays a major role in insulin production, as blood sugar increases during their consumption.


The adrenal glands are responsible for making cortisol. It’s frequently called the “stress hormone” as physical and/or emotional stress prompts its release. Hydrocortisone and cortisone are the manufactured kinds of cortisol.

This is a catabolic hormone. This means that it breaks down tissue. As well as controlling inflammation, cortisol makes glucose available by breaking down muscle when the blood sugar is low. This commonly occurs during endurance activities when the circulating glucose supply gets depleted.


Epinephrine (which is also called adrenaline) is called the “fight or flight” hormone. This is because it acts quickly at times of stress to constrict arteries and raise blood pressure. This boosts the heart rate to deliver oxygen far more effectively. In addition, epinephrine constricts airways so that respiration is more efficient.

On top of all of this, epinephrine directs the muscles and liver to give up their glucose stores during strenuous activity. In this way, epinephrine is a catabolic hormone, just like cortisol.


Glucagon acts like a mirror hormone of insulin.  When you fast or eat a low-carb diet, glucagon responds more efficiently than insulin to replenish low glucose supplies.

Glucagon instructs the liver to “surrender” its glucose stores. It also breaks down muscles to increase cortisol, which stimulates the production of glucose. If insulin is anabolic, then glucagon is catabolic.


Estrogens are a group of steroid hormones that regulate the normal sexual and reproductive development of women. They’re also the sex hormone as they play a role in desire and arousal. For this reason, non-hormonal birth control is now readily available, and women who are looking to build muscle may wish to opt for this option too. A woman’s ovaries make most of the estrogen. However, the adrenal glands and fat cells make small amounts of these hormones too.

female runner sprints to build enduranceSource: Courtesy of CrossFit Inc.

Estrogen has a remarkable effect on musculoskeletal function. Beyond the known relationship between estrogen and bone, it directly affects the structure and function of other musculoskeletal tissues, such as muscles, tendons and ligaments. In these other musculoskeletal tissues, estrogen boosts muscle mass and strength and then increases the collagen content of connective tissues.

However, unlike muscle and bone where estrogen improves function, in the ligaments and tendons, estrogen decreases stiffness. This decrease affects injury rates and athletic performance. High estrogen levels can lead to a decrease in power and performance, and they make women more vulnerable to ligament injuries.

What is the natural muscular potential of women?

First, let’s have a look at how the natural muscular potential of women compares to that of men.

Percentage-wise, how much muscle can a woman build compared to a man? Does testosterone play a huge role, meaning that women will generally build 7% less muscle than men men? Is it about half?

It’s 100%.

With strength training, women build the same percentage of muscle mass as men. When normalized to muscle mass, women can gain as much size, and occasionally more strength, than men. The only difference is the starting point: men begin with far more muscle mass and more strength. The relative increase in muscle size is the same when comparing men and women.

Research surrounding protein metabolism reaches the same conclusion. Females build just as much muscle after strength training and after meals as men do. In fact, one study concluded that within the same level of muscle mass, women have a greater rate of muscle protein synthesis than men.

That being said, female athletes can’t generally develop as large muscles as male athletes because they don’t have as much muscle mass to begin with. Additionally, testosterone (the main muscle-building hormone) plays a big role in differences in muscle mass gains, allowing those with higher testosterone levels to build more muscle in the long run.

Will lifting weights make women bulky?

A common myth about heavy weight training, particularly among women, is that lifting heavy weights will lead to a bulky physique. It’s quite true that lifting heavy will promote hypertrophy in muscles and this will lead to a size increase. However, the idea that weight training leads to a “bulky” look is factually incorrect.

The true culprit that leads to “bulky” physiques is fat accumulation.

Excessive body fat is what results in both men and women looking bulky. The most important facet of someone’s physique is his or her body fat percentage. A good physique nearly always requires a fairly low body fat percentage. Lifting heavy weights can assist with accomplishing this.

Athlete competes in the CrossFit Games, the ultimate test of fitnessSource: Courtesy of CrossFit Inc.

Heavy weight training has several benefits that can help to develop muscle, shed fat, and eventually lead to anyone’s desired physique.

Here are some of the advantages of heavy lifting:

  • Stronger muscles, tendons, and ligaments that lead to more stable joints and overall movement
  • Increase in muscle size (greater in men than in women)
  • Decrease in body fat due to burning calories and favorable hormonal balance

It’s important to remember that any exercise regimen is only as good as the diet that goes along with it. Regarding physique changes, diet accounts for a lot more than the exercise itself. Obviously, you need to weight train to build muscle. However, it will all be for nothing if your diet is not aligned with your training program.

Although women generally have to work harder to build the same amount of muscle mass than men, it’s still possible for women to have increased muscle definition. And many of the hormones naturally produced in the body are there to offer a helping hand.

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