The 6 Hormones That Optimize Muscle Building

Everyone can appreciate the importance of an exercise program and good nutrition when trying to achieve fitness goals.
These are the foundations for muscle growth, staying lean, looking good, and feeling great. Hormones are another piece of the fitness puzzle.

Hormones are chemical messengers released by the body as a response to a stimulus. They carry messages such as increasing muscle growth or decreasing blood sugar. For example, when you ingest food, your body is stimulated by high sugar in the blood stream. It sends a message to the pancreas to release insulin. Insulin then helps move sugar from the bloodstream and into the cells where it can be used for energy. Hormones “live” in various glands within our body. They reside here until they are called to action by the body based on a response to a certain stimulus. The following diagram shows the location of the major endocrine glands. These are the type of glands that can make, house, and release hormones. This article will review various hormones and make references to glands found in the body. Refer to it to gain a better understanding of the glands’ locations.

Along with diet and exercise, hormones have a huge effect on the body’s ability to build muscle, lose fat, go fast, or go far. Because they are rarely understood, they are not a source of focus for many exercise enthusiasts. This article will review major hormones, what they do, and how we can use them to our advantage.


hormones optimize muscle building

Testosterone peaks while men are in their 20’s. A gradual decline begins after about age 30. Image courtesy of:

Testosterone is perhaps the most widely recognized hormone related to muscle growth.

It is primarily created in the testes, with minimal amounts also created by the ovaries. Testosterone helps increase size by interacting with the muscle tissue itself to elicit growth.

It can also increase strength by increasing the interactions within the nervous system. This improves the “brain to muscle” connections. Women have up to 20 times less testosterone concentration when compared to men. This is one of the main reasons why women will not naturally get “bulky” even when lifting heavy weight. Testosterone peaks while men are in their 20’s. A gradual decline begins after about age 30. Insufficient levels exist in prepubescent boys to help them see big gains in muscle mass. Some studies suggest that obesity, diabetes, smoking, and a sedentary lifestyle can lead to further declines in testosterone. You can increase the release of testosterone by working large muscle groups with lots of sets and lots of reps. Weight should be heavy and can be 85%- 95% of your max, or a rep range of 5-10. Perhaps the biggest key is keeping rest to between 30-60 seconds.

Growth Hormone

Growth hormone is also called somatotropin and it is released by the pituitary gland.

As the name implies, growth hormone is responsible for the development of a child. It also plays a huge role in the growth of muscle.

Growth hormone may decrease your body’s reliance on glucose for energy as it increases its use of fatty acids. This can lead to decreases in body fat while maintaining or increasing muscle mass. Research shows that growth hormone release increases with heavy weight and a rest period of 1 minute. Using a weight that would allow completion of 10 reps provides better results for GH increases than a weight that only allows completion of 3-8 reps. There is a great release of growth hormone during sleep. This release is essential for tissue repair. You can’t skimp on sleep when trying to gain muscle mass! Insulin growth factor 1 responds to releases in growth hormone. IGF1 has anabolic (muscle-building properties) much like insulin. Focusing on things that release GH will give you the added benefit of also releasing IGF1.


Cortisol is released by the adrenal glands.

These glands are known to be primary players in the fight or flight response by the body to stress. Responses related to fight or flight include increased heart rate, sweating, and increased alertness.

In order to fuel these responses, the body requires energy. It will get the energy from glucose if enough is available. If glucose is not available freely in the body or from storages in the liver/muscle, cortisol signals for the breakdown of protein in order to get the energy it requires. Where does this protein come from? Your muscles! Cortisol is therefore known as a catabolic, or muscle-breaking, hormone. Testosterone and insulin have an opposite effect. These hormones are anabolic, or muscle-building. Catabolic and anabolic hormones fight for the same receptors in order to express their desired effect. Who do you want to win? Muscle building or muscle breaking?

Cortisol has also been shown to decrease immunity. This makes recovery more difficult and increases the chance for infection and/or illness. Cortisol is released in response to stress, and exercise puts stress on the body. It is therefore nearly impossible to gain the benefits of exercise without releasing cortisol. Cortisol will respond to any stress. It is important to keep stressors in your life under control to help decrease the negative effects of catabolic hormones. Vary sets, reps, and rest during exercise. Make sure you include some recovery weeks in your training program. The following are tips to help keep stress low:

  • Get 7-9 hours of sleep
  • Meditate
  • Take mind/body classes such as yoga
hormones optimize muscle building

These glands are known to be primary players in the fight or flight response by the body to stress. Responses related to fight or flight include increased heart rate, sweating, and increased alertness. Image courtesy of:

In contrast to all of the other hormones reviewed in this guide, you will want to maintain low cortisol levels.

Epinephrine, Norepinephrine, Dopamine

These hormones are released by the adrenal medulla when the body is stressed by a natural event or intentionally via exercise.

A release of these hormones increases energy availability, blood flow, the ability of muscles to produce force, and the force of contraction. All of these effects are beneficial when looking to make fitness gains.

These hormones respond to short rest periods (30-60 seconds), heavy weight (failure at 10 reps), and high volume (3-4 sets of 8-10 exercises). It is important to note that rest, recovery, and training variety are of necessary when trying to regulate adrenal hormones. When adrenal glands are under too much stress for too long they can fatigue and fail to work properly. At this point, there are usually negative effects from cortisol, protein breakdown, and a suppression of the immune system.

Thyroid Hormones

Thyroxine and Triiodothyronine are two hormones produced by the thyroid gland.

hormones optimize muscle building

Aside from perhaps testosterone, thyroid hormones play one of the most important roles when training to gain mass. Thyroid hormones are beneficial for anyone wanting to lose or gain weight. Image courtesy of:

They are activated through a chain reaction of hormone interactions and pituitary gland involvement. They control metabolism, increase the making of protein, and can influence other hormones such as epinephrine.

Aside from perhaps testosterone, thyroid hormones play one of the most important roles when training to gain mass. Thyroid hormones are beneficial for anyone wanting to lose or gain weight. An under active thyroid hormone can cause fatigue and slows metabolism. This decreases your ability to burn fat. An overactive thyroid hormone can increase the brittleness of bones. This may lead to fractures. As with most things in the body, maintaining a balance of these hormones is crucial. Thyroid hormones require ingestion of iodine via food in order to work properly. Iodine is a mineral that is found in eggs, seaweeds (i.e. kelp and nori), iodized salt, cod, and dairy products. Recommended daily iodine intake for healthy adults is 150 micrograms. During pregnancy and lactation, this amount rises to 220 mcg and 290 mcg respectively.


Insulin is a very effective anabolic, or muscle-building, hormone.

It is released by the pancreas in response to the consumption of food. Insulin helps the body remove sugar from the bloodstream.

It carries it to the cells where it is needed for energy to fuel cell functions. Once these cells are “full,” insulin assists your body in energy storage by driving sugar into your fat cells. One key to prevent excess fat storage is to maintain stable blood sugar levels, and therefore insulin levels, throughout the day. Massive caloric intake, preceded by little food and with no food consumed for hours after, leads to a sugar/insulin spike with a corresponding crash. During these periods of fasting and feasting, insulin is called by the body to shuttle sugar into cells. The body perceives itself being in starvation mode. It attempts to store excess calories in the form of fat just in case it is starved again. One final message your body sends during these spikes and crashes…if you need energy, start breaking down muscle first.

Insulin is extremely beneficial for fueling muscles. However it must be controlled to offset its potential negative effects. Eat frequent, well-balanced meals during the day. Attempt to break your caloric intake into 5-6 meals per day, with the first meal beginning within 20 minutes of waking up. Simple sugars (candy, juices, soda) and easily digested carbs (potatoes, white bread) cause more of an insulin spike that complex carbohydrates (whole grains).

That is why complex carbs are recommended for most times of the day. Exercise will cause your body to be more efficient at absorbing blood sugar. Therefore it will be less reliant on insulin. If less insulin is required, then less insulin is released. This leads to a less dramatic spike/crash.


Glucagon is often seen as insulin’s opposite.

While insulin attempts to store energy in the cells, glucagon releases energy from the cells and into the bloodstream. Glucagon is called into action when the body senses low blood sugar.

The body understands that low blood sugar can lead to unavailability of energy to drive basic actions such as brain function and muscle contraction. While glucagon requests some energy release from fat cells (yeah!), it may also request protein for energy. This can lead to a breakdown in muscle. Glucagon, like insulin, responds to food timing. Unlike insulin it is less affected by food type. Your body uses insulin and glucagon to maintain a happy balance of available energy. Help your body accomplish this balance by eating meals on a regular schedule. Avoid skipping meals, and make sure meals are well-balanced with carbohydrates, fats, and proteins.


As you can see, hormones are essential components for muscle growth.

They are important for increases in size, endurance, and power. There is no one best exercise nor is there one best set/rep scheme.

Variety will be key in ensuring release of all necessary hormones, and in preventing plateaus from occurring. It is important to have a general conditioning phase, a strength phase, a power phase, and a muscular endurance phase. Each of these phases will require specific exercise selection and ideal sets/reps/rest. Nutrition plays a critical role in performance, recovery, and hormone control. Recovery days, sleep, and stress management are also components that need to be part of a well-balanced program. Many athletes fall into a trap of not going hard enough on training days and then not recovering well enough on easy days. Be smart with your training, eating, and resting. Your hormones are watching, and waiting to respond.

About the Author

Aaron Punsalan - JMax FitnessAaron writes for Gym and Fitness, a retailer of power racks, treadmills and other gym supplies in Australia. He is also a huge sports-fanatic. During his spare time, he is either doing push ups or watching game highlights. Well, sometimes he does them both at the same time.