Testosterone replacement therapy (TRT) in men with low testosterone has consistently shown to produce positive benefits with minimal side effects. Also, benefits of testosterone therapy can be both physical and mental. Restoring testosterone levels to within the normal range by using testosterone replacement therapy has shown to:
- Increase lean body mass
- Decrease fat mass
- Increase bone mineral density
- Improve sexual function
- Improve mood and well-being
Although some benefits appear in the first month of therapy, most effects begin to take place over the first few months. Learn more about these specific positive benefits of testosterone therapy below.
A Note on TRT
All these benefits have made testosterone replacement therapy usage increase substantially over the past several years. While TRT is usually well tolerated as long as testosterone is kept within normal, physiologic levels, side effects can occur. It is important for you and your physician to be aware of different administration methods and potential side effects.
Page Table of Contents
Increase in Lean Body Mass
Testosterone replacement therapy produces a moderate increase in lean body mass (muscle mass) in men with low testosterone.1-9 TRT users typically gain between three and six pounds of lean muscle mass in the first six months of treatment.
Why’s That Important?
As a man ages, he loses muscle mass, typically about 0.5 to 1.0% per year after the age of 40. This loss becomes progressively faster after the age of 40 and is worse if he has low testosterone.10 Muscle contributes a great deal to an individual’s resting metabolism. Therefore, losses in muscle slow down resting metabolism.
The increase in muscle mass brought about by testosterone therapy can be highly beneficial. It increases your lean body mass and thus raises your metabolism. The higher your resting metabolism, the more calories you burn at rest and the less likely you will be to put on any excess fat as you age.
Do not, however, worry about becoming muscle bound. TRT users typically gain between three and six pounds of lean muscle mass in the first six months of treatment.1-7 Once testosterone levels are stabilized within normal range, increases in muscle mass typically taper off. This stabilization usually occurs after about six months of treatment.
Expanded Detailed Explanation
In trials of TRT for elderly men, the benefits of testosterone on body composition (muscle mass and fat mass) and strength have been the most extensively studied area of research. Studies show that testosterone administered to men with low levels has a tendency to increase lean body mass.1-9 These results occur over a wide array of administration methods, including transdermal skin gels,3 scrotal patches,4 oral pills,5 and intramuscular injections.1,2,6,7 This increase in lean body mass is not surprising considering testosterone has muscle building effects, including protein synthesis, increasing muscle fiber cross-sectional area, and reducing muscle degradation.6
Decrease in Fat Mass
Testosterone therapy produces a moderate decrease in fat mass, especially abdominal fat mass, in elderly men with low testosterone.1,3-7,11-14 Typical fat loses range between five to ten pounds in the first six months of TRT treatment.
Why’s That Important?
As men age, they typically gains fat mass, especially abdominal (AKA visceral) fat. Besides giving you an undesirable gut, this increase in visceral fat increases the incidence of cardiovascular problems. TRT for men with low levels can keep you thinner and healthier since long-term studies consistently show a decrease in fat mass.
Expanded Detailed Explanation
In trials on TRT for elderly men, the effects on body composition and strength have been the most extensively studied area of research. Studies indicate that testosterone administration in men with low levels consistently decreases fat mass with rare exceptions. 1,3-7,11-15 A large number of studies have documented that abdominal obesity is associated with low total levels.16-19 Returning levels to normal physiological levels with TRT may reverse this fat deposition in the abdomen while simultaneously increasing muscle mass.
Increased Bone Mineral Density
Evidence shows that the benefits of testosterone therapy include the slowing or even reversing of the loss of bone mineral density due to decreased testosterone levels associated with aging.4,20-25
Why is Bone Mineral Density Important?
Osteoporosis and consequent fractures are NOT just a women’s health problem. This problem belongs to men just as it does to women. Hip fractures are not uncommon for men over the age of 65.23,24 Not only will a hip fracture or a fracture of another bone cause you to lose your functional independence, but it will also significantly increase your likelihood of death, particularly within one year of the fracture.7 One of the primary benefits of testosterone therapy is an increase in bone mineral density.
Expanded Detailed Explanation
Many studies indicate that one of the primary benefits of testosterone therapy is the prevention of bone loss.4,20-25 These studies showed an increase in bone mineral density at the lumbar spine compared to placebo controlled groups. One study reported no change in bone mineral density in the group receiving TRT but a small significant decline in bone mineral density in the placebo group.3 Thus, TRT resulted in an overall positive treatment. It also shows that, while TRT may not increase bone mineral density, it may slow and/or prevent decreases in bone mineral density typical of aging.
Improved Sexual Function
There are two essential elements of sexual function: tactile sensation (physical contact) and mental stimulation (thoughts and visual images as known as libido). When given to men with low testosterone, TRT increases sexual thoughts and sexual desire.26-28 So, testosterone benefits libido.
The benefits of testosterone therapy on physical sexual function are not conclusive. Erectile dysfunction can be related to one or more of many potential underlying medical conditions unrelated to testosterone levels. Thus, taking testosterone may not necessarily fix these unrelated underlying problems. Nevertheless, recent reviews on the effects of testosterone on erectile potency are encouraging.29-31 Also, in certain instances, testosterone used in conjunction with PDE-5 inhibitors (like Viagra) improves erectile function more than PDE-5 inhibitors alone.32-36
Improved Mood and Well-Being
Low testosterone is associated with behavioral changes that include decreased mood and well-being as well as depression. Due to the aforementioned association between low testosterone and decreased mood, it would make sense that testosterone benefits mood and well-being.
Some studies on the effect of testosterone therapy have shown testosterone benefits mood and overall quality of life as well as depression.4,22,37,38 Other studies have shown no benefit of TRT on these factors.3,15,39,40 Anecdotal evidence shows that many men do have an enhanced sense of well being from TRT. Nonetheless, these positive effects are not consistent and have yet to undergo rigorous scientific evaluation.
The Take Home Message
Testosterone replacement therapy is not a cure-all answer for mood disorders associated with low testosterone of aging. Depression is a serious problem. In fact, it is the most common psychiatric disorder in older men. If you are depressed, you are not alone. It is important to be aware that while TRT may help mood and well-being, it will not definitely cure your depression. Thus, if you think you may suffer from depression, talk to your physician or other medical professional.
External Resources: NCBI: Benefits of Testosterone Therapy
Updated: May 4, 2015
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