Testosterone Supplementation and Older Males

Written by Ben Bunting: BA(Hons), PGCert. Sport & Exercise Nutrition. British Army Physical Training Instructor.


Testosterone replacement therapy (TRT) is an important factor to help you build muscle. Although it can be very effective, it can also cause side effects.

In order to make sure you're not dealing with negative effects from TRT, you need to take some time to understand what it is and how it affects your body.

Testosterone and Males

Testosterone is the primary sex hormone in males. It is produced in the testes and is released in the bloodstream. It affects muscle mass, bone density and libido. A low level of testosterone may cause decreased sex drive.

It is important for sperm production and helps keep males fit. In addition, testosterone may promote bone and muscle growth

Since a man's testosterone levels vary throughout the day, there are a number of ways to measure them. Blood tests and saliva tests are common methods. Some labs use different measurement techniques. Others use more sensitive measures.

The best time for testing is in the morning. This is when the levels tend to be highest. If the result is low, you might want to assess your diet, activity levels and other lifestyle choices. 

Increasing moderate to high testosterone levels could be a promising avenue for treating cognitive difficulties in older men. Studies are still ongoing to determine if these increases are effective. Moreover, it is possible that personality differences may play a role in moderating the effect of hormones.

Does TRT affect muscle mass?

The results of TRT on muscle performance and function are varied. Some studies have found that testosterone therapy is associated with small increases in body weight and lean body mass, while others found that it TRT does not increase strength.

Some studies have shown that testosterone has a positive effect on self-reported physical function, and testosterone has been shown to reduce age-related decline in aerobic capacity and physical fitness while other studies have also reported that it can improve muscle size and strength.

Put simply, there's lots of contradictions and purported benefits, but this could be down to the study protocols, participants amongst other variables.

However, the clinical impact of these changes is uncertain. While the effects of testosterone on muscle strength and power are not well understood, a meta-analysis conducted in 2018 suggests that testosterone replacement therapy may improve overall physical performance.

Testosterone's Effects on Atherosclerosis Progression in Aging Men (TEAAM) trial

Among the largest trials to test the effects of testosterone on muscle strength and function is the Testosterone's Effects on Atherosclerosis Progression in Aging Men (TEAAM) trial.

It is a three-site randomized, double-blind, placebo-controlled trial conducted at the Boston University Medical Center, the Kronos Longevity Research Institute in Phoenix, and Charles Drew University in Los Angeles.

TEAAM Trial has several strengths, including a well-designed study design, an intent-to-treat analytical strategy, and a pre-specified per-protocol sensitivity analysis.

As part of the study, the men had a variety of assessments at baseline and after the study ended.

These included body weight, muscle strength and fatigability, and a battery of performance measures.

Results showed that the testosterone-plus-exercise group had greater gains in muscle size and strength than did the testosterone-alone or placebo-plus-exercise groups.

Gold Standard Research

The randomized, placebo-controlled, 3-year trial, the TEAAM Trial, was conducted at three sites.

The primary aim was to determine whether testosterone supplementation would slow the progression of atherosclerosis in older men with low testosterone.

Participants were recruited through local newspapers. Each study was a randomized, double-blind, parallel-group study. All subjects provided informed written consent.

The TEAAM Trial had several strengths. First, it had a prespecified intent-to-treat analytical strategy.

Secondly, it was approved by several institutional review boards, including the Western Institutional Review Board in Puyallup, Washington and the Harbor-UCLA Research and Education Institute in Los Angeles, California.

Thirdly, it had a good trial design, which allowed for better assessments of muscle performance.

In addition, the TEAAM Trial was one of the longest trials to date. During the course of the trial, 256 participants were assessed at baseline and after the end of the treatment period.

Among these, 106 were assigned to the testosterone arm, while 97 were in the placebo arm. Throughout the duration of the trial, all participants received five testosterone injections per week.

TRT Physical Benefits

Many studies have shown that testosterone supplementation leads to an increase in muscle size and function.

However, the clinical meaning of these results remains unclear. The TEAAM Trial is one of the longest testosterone trials in which muscle strength is evaluated as a primary outcome.

Testosterone replacement therapy for three years was associated with modest improvements in chest-press strength.

This was accompanied by a modest improvement in stair-climbing power. In addition, testosterone and exercise were associated with modest gains in fat-free mass. 

The testosterone and exercise groups had greater increases in strength, fat-free mass, and quadriceps area.

These findings indicate that testosterone supplementation can be effective in improving muscle function and function-based physical performance in older men.

Compared with the placebo group, the testosterone and exercise groups had a more substantial increase in squatting weights. However, the effects of the treatment on mood and behavior were not clear.

The TEAAM trial included a masked random allocation to interventions. Among its strengths, this study had an excellent design.

military muscle testosterone booster banner

TRT vs Placebo

There have been a number of studies examining the effects of testosterone supplementation on muscle performance and function.

These studies vary in their design and measurement methods, but they show that testosterone supplementation can have an effect on muscle strength.

In most of these studies, testosterone was compared to placebo. The results showed that the group receiving testosterone and exercise had significantly increased strength and size of the legs, arms, and chest.

This result was supported by a subsequent study that measured changes in body weight and fat-free mass.

Other studies of testosterone therapy examined the effects on muscle fiber hypertrophy. These studies also showed that the use of testosterone increases lean mass in the legs, arms, and trunk.

A recent meta-analysis of research on testosterone replacement therapy indicates that physical performance may be improved in men. However, more research is necessary to determine the long-term safety of this treatment.

TRT and Exercise

Testosterone is similar to resistance training, as the benefits from both are believed to be largely additive.

One study found that testosterone supplementation in addition to a resistance training intervention produced superior gains in muscle size and strength.

In this study, testosterone plus resistance training led to greater increases in squatting strength and endurance than did placebo alone.

The magnitude of this increase was unclear. Similarly, the effects of testosterone plus no training were less pronounced.

TRT 's effect on Fatigue

Testosterone has been known to improve muscle strength, bone mass and fatigue. It also may have effects on muscle size and fatigability, depending on the concentration and dose of testosterone used.

However, these effects are not well documented. One study aimed to evaluate the effect of testosterone administration on muscle performance, specifically leg press strength.

A single-site, randomized, placebo-controlled clinical trial was conducted. Testosterone was administered at 125, 300, and 600 mg/week.

Leg press strength and leg fatigability were measured after 20 weeks of treatment. Results showed significant increases in both measures.

Leg power is essential for generating rapid, explosive movements. This type of function has been found to be associated with functional activities in older men.

Testosterone has been shown to decrease in men as they age. A decline in testosterone results in loss of lean muscle tissue.

Low testosterone levels can also cause low energy and fatigue. Therefore, it is suggested that testosterone should be monitored and prescribed when needed.

In addition to increasing muscle strength, testosterone supplementation increases capillarity density.

Combined resistance training and testosterone supplementation generally yields greater strength gains than either intervention alone.

The changes in muscle performance and muscle function due to testosterone dose were analyzed using paired t tests and analysis of covariance. For changes in total testosterone, the correlations were statistically significant.

Similarly, changes in muscle fatigability were not significantly correlated with serum free testosterone or IGF-I concentrations.

These measurements were taken after twenty weeks of testosterone administration and before the administration of the placebo.

Testosterone replacement therapy appears to attenuate age-related decline in muscle strength and function. Therefore, further research is needed to understand how it can be used in clinical practice. 

Lean body mass

Testosterone is a hormone that is essential to normal muscle growth. Low levels can prevent optimal hormonal balance, which can prevent proper body repair. It also signals the body to produce more lean muscle tissue.

One natural way to boost testosterone is through exercise. This can increase the size and strength of your muscles, as well as increase your overall body weight.

Some studies have suggested that testosterone replacement therapy may reduce the rate of age-related decline in muscle power and physical function. However, the clinical relevance of these findings remains undetermined.

There are different potential factors that could influence the efficacy of testosterone supplementation on muscle performance and function.

These include the level of testosterone in the body, changes in total lean mass, and changes in body weight, fat free mass, and muscle fatigability.

Studies have suggested that supraphysiologic (i.e higher doses than normally produced) doses of testosterone may increase the strength and muscle size of normal males.

The effect of testosterone on muscle strength has not been thoroughly studied in older men.

A recent systematic review of 21 randomized controlled trials (RCTs) found that testosterone was associated with increased increments in lean body mass (LBM). As the testosterone level increases, so does the capacity for more physical activity.


Testosterone has been shown to increase muscle mass and function in healthy men. It also appears to attenuate the age-related decline in muscle size and physical function.

However, it is not clear whether the effects of testosterone supplementation on muscle performance and function in older men are clinically meaningful, the research certainly suggests that TRT combined with resistance exercise reaps the most benefit.

Studies that examined the effects of testosterone on muscle performance and function in older men have been conducted with a variety of study designs. Some studies included competitive athletes.

Others investigated frail elderly adults. They reported increased strength, lean body mass, and aerobic capacity. Although they had small sample sizes, they generally concluded that testosterone therapy had positive effects on muscle function.


Show All

Blog posts

Show All