5-alpha reductase inhibitors don’t affect muscle mass and strength which are increased due to usage of testosterone

According to a trial, the 5-alpha reductase inhibitor dutasteride (Avodart) doesn’t affect muscle mass in healthy males that use testosterone.
A study connected with this issue was conducted. While fat-free mass was increased by 0,6-7,1 kg during 20 weeks in men that used dutasteride and Testosterone Enanthate, fat-free mass was increased by 0,8-8,1 kg in those that used placebo and testosterone. As for muscle power, sexual functions and volume of prostate, they didn’t differ in men of these two groups.
5-alpha reductase inhibitors are utilized clinically to cure benign prostatic hyperplasia (BPH) and androgenic alopecia. These are diseases that usually occur in middle-aged and old men.
DHT represents the chief metabolite of testosterone. But the function of DHT in human development is not is not understood. It is supposed that DHT plays important role in development of prostate and phallus.
Middle-aged and old males with decreased testosterone levels that take testosterone drugs have risks related to reduced muscle size and sexual disorders.
Scientists also study and develop nonsteroidal selective androgen receptor modulators (SARMs). It is affirmed 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 plays any role for androgen’s effects on hematocrit, hemoglobin, lipids and certain other factors.
Shalender Bhasin and his colleagues at the Boston University have conducted a clinical trial in order to see whether 5?-reduction to DHT is needed in order to mediate androgen’s effects on muscle mass. Moreover, the experts evaluated role of 5?-reduction on sexual activity, hematocrit and levels of lipid.
The research conducted by Bhasin and his colleagues enrolled healthy men who were 18- 50 years old and had normal testosterone levels. They used Testosterone Enanthate and dutasteride or placebo. Dosages of Testosterone Enanthate varied from 50 to 600 mg weekly.
Since 5 ?-reductase inhibitors enhance testosterone levels, all males were given also gonadotropin-releasing hormone agonist in order to block natural testosterone.
The results of the research displayed that fat-free mass was enhanced due to usage of testosterone. It didn’t differ significantly in males of these 2 groups. Muscle strength which was also increased due to intake of testosterone didn’t differ between the two groups too. Sexual functions, volume of prostate, sebum production, hemoglobin, acne, hematocrit didn’t differ essentially between those who were given placebo and dutasteride.
The experts state that effectiveness of 5?-reductase inhibitors may be limited in males who have normal or enhanced testosterone levels. That’s why it is necessary to check levels of testosterone in order to set how bodies will respond to 5 ?-reductase inhibitors.
So, the study has manifested that muscle mass is not affected by 5?-reductase inhibitors.  Males should know that if they have enhanced testosterone levels or introduce exogenous testosterone in their bodies, 5?-reductase inhibitors will not lead to shrunken prostate.