How Does Testosterone Promote Muscle Growth? Protein Synthesis and Hormone Levels

Testosterone and Muscle Growth: How testosterone increases protein synthesis in muscles.

Why Testosterone is Key to Muscle Growth, Recovery, and Athletic Performance

Testosterone plays a major role in muscle growth specifically by increasing protein synthesis. This is the process by which the body builds new proteins, primarily in muscle tissue. This occurs when testosterone binds to androgen receptors that are located in muscle cells. It then triggers a series of cellular mechanisms which both enhances and speeds up the rate at which proteins are produced. This process directly leads to the growth and repair of muscle fibers, making them thicker and stronger. It is because of this process that men who take testosterone will notice an increase in muscle size and strength and be able to recover faster from workouts. Testosterone also helps burn fat which tends to lead to men on TRT having leaner more sculpted physiques.

In addition to directly stimulating protein synthesis, testosterone can increase the number of satellite cells, which are essential for muscle repair and growth. Satellite cells are stem cells in the body that play a vital role in not only muscle growth, but repair, and maintenance as well. During development, satellite cells proliferate and fuse with myofibers, increasing the total number of myonuclei. This is a similar process to what occurs in the muscles during exercise or when they are functionally overloaded. These cells will proliferate and then fuse with the existing muscle fibers, which contributes to the overall size and strength of the muscles. Testosterone’s effect on protein synthesis is one of the key reasons why it is so effective at increasing muscle strength and mass and why testosterone levels are so closely related to strength and athletic performance.
 
What is the role of testosterone in muscle repair and recovery?
Testosterone plays a major role in both muscle repair and recovery, particularly after intense physical activity whether it be from exercise or say use in a physical job. When you exercise and lift weight, the muscles will experience slight micro-tears. The harder one works out, the more tears are experienced which is a reason why one feels sore and tired the days after an intense workout. When the muscles experience micro-tears during exercise or intense physical labor, testosterone helps by accelerating the repair process. It does this by enhancing protein synthesis within the muscles allowing them to heal and grow back stronger. This is demonstrated with an increase in muscle mass and shorter recover time.

Additionally, testosterone can reduce the levels of cortisol in the blood stream. Cortisol is a catabolic hormone, that is associated with stress, causing inflammation and can break down muscle tissue and slow the recovery process. By keeping cortisol levels in check, testosterone ensures that the body remains in an anabolic state, promoting muscle growth and reducing recovery time. This dual action—enhancing protein synthesis and mitigating muscle breakdown—makes testosterone crucial for efficient muscle repair and overall athletic performance. Reducing cortisol levels isn’t easy but here are a few steps .to take which can help focus on stress management and lifestyle changes such as relaxation techniques, such as yoga or meditation. Try to improve sleep quality and duration, exercise regularly and maintain a healthy diet. Avoid unnecessary stress whenever possible (although this last one is easier said than done!)

Whats its impact on strength and athletic performance?

Testosterone significantly impacts strength and athletic performance by increasing muscle mass and enhancing muscle fiber size and density. Its impact on athletic performance can easily be seen by just looking at the world’s best athletes and their body types. It allows for athletes to run faster, jump higher, throw farther etc… To gain an competitive edge, many athletes will opt to take performance enhancing drugs which are often times, synthetic androgens such as Nandrolone (Deca-Durabolin), Stanozolol (Winstrol), Dianabol (Methandrostenolone), Trenbolone as well as testosterone. In athletic performance, higher testosterone levels are linked to faster recovery times, reduced fatigue, and improved energy levels, all of which contribute to better overall performance. Whether in strength training, endurance sports, or high-intensity activities, testosterone’s role in muscle development and recovery makes it a key factor in achieving peak athletic performance. There are also OTC testosterone boosters, however their effectiveness is questionable at best.

Testosterone also promotes neuromuscular adaptations, helping muscles generate more force, which directly translates to increased strength. Testosterone boosts the production of red blood cells, which improves oxygen delivery to muscles during physical exertion, leading to greater endurance and stamina. Famous Cyclist, Lance Armstrong used Erythropoietin (EPO) to increase red blood cell production. Erythropoietin is a hormone naturally produced by the kidneys that will stimulate the production of red blood cells in the bone marrow. Originally developed to treat anemia caused from chronic kidney disease or for cancer patients undergoing chemotherapy, EPO because popular with athletes due to its ability to increase endurance during competitive events. 

More red blood cells enhance oxygen delivery to muscles, improving endurance and performance, especially in endurance sports like cycling, running or even in combat sports like boxing or MMA. This leads to reduced fatigue and a competitive advantage in high-intensity aerobic activities. It wasn’t able to be detected for a while but now tests have been developed and EPO is banned from competitive sports, as are the other androgenic steroids, however athletes will still take risks due to the increased performance benefits they can achieve from taking them.

Importance of Optimal Testosterone Levels for Muscle Mass.
So just what are the consequences of low testosterone levels on muscle growth?

There are several negative effects from having Low testosterone which can significantly impact muscle growth. Because testosterone is a key hormone in both men and women it affects many different important function but it plays a particularly prominent role in promoting muscle mass, strength, and overall physical vitality. When testosterone levels are too low, several negative effects on muscle growth and overall physical health can occur:
Reduced Muscle Mass As previously discussed, Testosterone stimulates protein synthesis, which is essential for building and repairing muscle tissues. Low testosterone reduces this process, which leads to muscle atrophy or a decrease in muscle size. Over time, individuals with low testosterone may notice a decline in muscle mass, making it harder to maintain or grow muscles even with regular exercise. Just look at former body builders as they age. It’s impossible to maintain that amount of muscle mass without adequate testosterone levels, exercise and diet. As we get older, our testosterone levels will decrease and both size and strength of our muscles decrease accordingly. Muscle strength is likely to decrease as well because muscles become less responsive to physical training, leading to weaker contractions and overall reduced power. People with low testosterone may find it harder to lift weights or perform strenuous physical activities they were previously capable of. Another negative side effect from Low T is

Increased Fat Accumulation. Low testosterone is often associated with an increase in body fat, particularly in the stomach/abdominal region. This is due to testosterones role in regulating fat metabolism. With lower T levels, fat accumulation will increase, which cause muscle mass to decrease. This cycle creates an unfavorable body composition (higher fat-to-muscle ratio) and men begin to look less tone and “softer”.

Difficulty Maintaining Muscle. Even for those people who already have significant muscle mass, the problem becomes maintaining that muscle. It becomes especially challenging when testosterone levels drop. The body becomes more catabolic (breaking down tissue), which makes it very difficult to preserve and significant muscle gains without sufficient hormonal support.

Slower Recovery Time. Testosterone also helps in the recovery process post workout by helping repair muscle fibers which get damaged during exercise. Individuals with low testosterone may experience longer recovery times, feel increased muscle soreness, and be at a greater likelihood of getting injured, due to their bodies being less efficient at repairing muscle tissue. Often you hear about athletes taking steroids not to help build bigger stronger muscles, but rather to help them recover to endure a long competitive season. In the NFL, they typically have a week to recover and in the MLB they often play every day all summer long. Higher testosterone levels allows these athletes the ability to recover faster to perform at the highest level possible.

Decreased Motivation and Energy. Low testosterone can often lead to fatigue, reduced energy levels, and a lack of motivation. This will make it harder for individuals to engage in regular exercise or maintain an active lifestyle and this increases muscle decline, lowers testosterone levels, increases fat and exacerbates the problem.

Increased Risk of Sarcopenia. Sarcopenia is the age-related loss of muscle mass and function. Over time it happens to all of us, the question is by how much? Low testosterone levels can accelerate this process, especially in older adults, which then leads to a more pronounced decline in muscle health. This will make individuals more frail and weak and can increase the risk of injuries sustained from things like falls, fractures, and other health issues related to reduced mobility and strength lowering quality of life and decreasing health in the procress.

Impaired Performance in Resistance Training. Patients with low testosterone often find it harder to make significant gains in strength and muscle size even when following a structured resistance training program. The same workout routine is no longer yielding the same results. The hormone's role in muscle growth means that, without adequate levels, it becomes harder to stimulate the necessary adaptations that lead to hypertrophy (increase in muscle size). To compensate, one must workout harder and longer which can be tough to do with lower testosterone levels decreasing both energy, performance and recovery time.

Psychological Impact. Testosterone is linked not just to muscle growth and physical health but also is has a major affect on mood and cognitive functioning. Low levels can lead to serious psychological issues like depression, anxiety, and a decrease in self-esteem and confidence, which can further undermine a person’s motivation to engage in muscle-building activities like weightlifting or exercise. Because low testosterone levels have profound effects on muscle growth and overall physical health, it’s important to be aware of your hormonal health and test for low T. Addressing low testosterone, either through lifestyle changes, medical intervention, or testosterone replacement therapy (TRT), can help mitigate these effects and support muscle growth and maintenance and allow for a better quality of life and overall health as we age.