As with a number of treatments or medicines that have been around for a long, long time, it hasn’t been scrutinized like a new drug would be. And although they’ve been discussed, there aren’t any large-scale, randomized controlled clinical trials of testosterone-replacement therapy under way. [See “A male equivalent to the Women’s Health Initiative?” below.]
Increased testosterone can have an impact on body composition. Possible benefits include gains in lean muscle mass, reduced body fat and increased bone density. Testosterone inhibits uptake of triglycerides and increases lipid mobilization from adipose tissue, and the increase or decrease of testosterone will usually have an inverse effect on fat stores, with higher testosterone generally causing a decrease in body fat. "The Journal of Clinical Endocrinology and Metabolism" published a study in 2007 that showed decreases in body fat and increases in lean mass in HIV-positive obese men given testosterone therapy. In 1989, a study of the effects of testosterone on muscle mass at the University of Rochester School of Medicine and Dentistry suggests that increasing testosterone increases protein synthesis in muscles. Body composition changes from increased testosterone were also demonstrated in a 1999 study at the School of Exercise Science and Sports Management, Southern Cross University in Australia performed on male weight-training subjects, which showed increases in arm girth and body weight and decreased body fat following a 12-week cycle of testosterone enanthate.

*IMPORTANT TESTOSTERONE TREATMENT WARNING: Who Should Not Enroll in Testosterone Replacement Therapy? Men who have or had prostate cancer or breast cancer should not take testosterone replacement therapy. All men considering treatment should undergo a thorough prostate cancer screening prior to starting any therapy program with a rectal exam and PSA test. *Men who have or have had cardiovascular disease, or are at risk for coronary disease, or have had a history of heart disease may not be candidates for testosterone treatment. Blood testing, thorough physical examination and careful screening by your physician is absolutely essential before considering a hormone therapy program of any kind. Always discuss the potential benefits, uses, side effects and risks of prescription hormones and steroid drugs with your treating physician. Hormone Treatment is for medically qualified candidates only. The FDA has cautions about using testosterone products for low testosterone due to aging; requires labeling change to inform of possible increased risk of heart attack and stroke with use - FDA Testosterone Safety Update


Discussing the clinical utility of these findings, Dr. Budoff told EndocrineWeb, “in the short-term, I am going to check my patients for atherosclerosis before instituting testosterone therapy. We still need a definitive study to show whether or not heart attacks are increased by supplemental testosterone, but advancing atherosclerosis is not a good thing. These results should make us more cautious about whom we treat and what doses we use.”

Both Beast Sports’ Super Test and iSatori’s ISA-Test contain a proprietary blend, which means they don’t disclose the amount of each and every ingredient in the mix. This is only a problem if there is an ingredient tucked into a proprietary blend for which we need to know an amount, like magnesium and zinc. While none of the ingredients in Beast Sports’s proprietary blend raised any red flags, iSatori’s blend contains melatonin, a hormone that helps regulate sleep. Melatonin is an ingredient that has a hard upper limit — Healthline suggests at most 10mg for an adult — and even lower doses can interact poorly with many medications. Since we can’t confirm whether the amount of melatonin in iSatori’s proprietary blend is under 10mg, we cut iSatori.


The effects of testosterone in humans and other vertebrates occur by way of multiple mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors.[113][114] Androgens such as testosterone have also been found to bind to and activate membrane androgen receptors.[115][116][117]

Hypogonadism is a disease in which the body is unable to produce normal amounts of testosterone due to a problem with the testicles or with the pituitary gland that controls the testicles. Testosterone replacement therapy can improve the signs and symptoms of low testosterone in these men. Doctors may prescribe testosterone as injections, pellets, patches or gels.
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