Specialists have studied connections between dutasteride and anabolic effects of testosterone

According to a trial, treatment with dutasteride (Avodart), a 5-alpha reductase inhibitor, doesn’t affect muscle mass in healthy men that take testosterone.
A study related to this issue was performed. While fat-free mass was increased by 0,6-7,1 kg during 20 weeks in men that were given dutasteride and Testosterone Enanthate, fat-free mass was increased by 0,8-8,1 kg in those that were given placebo and testosterone. As for muscle strength, sexual functions and volume of prostate, they didn’t differ in males of these two groups.
5-alpha reductase inhibitors are used clinically for treatment of benign prostatic hyperplasia (BPH) and androgenic alopecia. These are diseases which usually occur in middle-aged and old males.
DHT represents the main metabolite of testosterone. But the role of DHT in human development is not studied well. It is supposed that DHT has relevant role in development of prostate and phallus.
Middle-aged and elder men with reduced testosterone levels who use testosterone products have risks related to decreased muscle size and sexual problems.
Nonsteroidal selective androgen receptor modulators (SARMs) are also currently studied and developed. It is confirmed that SARMs and 5-alpha reductase inhibitors are safe because DHT is supposedly not necessary for effects on muscle mass, muscle power and sexual life. It is also doubted whether DHT has any role for androgen’s effects on hematocrit, hemoglobin, lipids and several other factors.
Shalender Bhasin and his colleagues at the Boston University have performed a clinical trial in order to define whether 5?-reduction to DHT is required in order to mediate androgen’s effects on muscle mass. Moreover, the specialists evaluated role of 5?-reduction on sexual functions, hematocrit and levels of lipid.
The research conducted by Bhasin and his colleagues implicated healthy men that were 18- 50 years old and had normal levels of testosterone. They used Testosterone Enanthate and dutasteride or placebo. Measures of Testosterone Enanthate ranged from 50 to 600 mg weekly.
Since 5 ?-reductase inhibitors increase testosterone levels, all men were given also gonadotropin-releasing hormone agonist in order to block natural testosterone.
The results of the study manifested that fat-free mass was increased due to application of testosterone. It didn’t differ substantially in men of these 2 groups. Muscle power that was also enhanced due to usage of testosterone didn’t differ between the two groups as well. Sexual activity, volume of prostate, sebum production, hemoglobin, acne, hematocrit didn’t differ essentially between those who administered placebo and dutasteride.
The specialists state that effectiveness of 5?-reductase inhibitors may be limited in males that have normal or high testosterone levels. That’s why it is important to check levels of testosterone in order to determine how bodies will respond to 5 ?-reductase inhibitors.
So, the research has shown that muscle mass is not affected by 5?-reductase inhibitors.  Men should know that if they have high testosterone levels or introduce exogenous testosterone in their bodies, 5?-reductase inhibitors will not cause shrunken prostate.