Since testosterone is the primary male androgen, we can also expect that the development of androgenic side effects. His expression is largely due to the speed at which the body converts testosterone into DHT. This substance is a metabolite of testosterone, which is responsible for development of certain androgenic effects that are associated with the use of testosterone cypionate. These include: increased secretion of sebum, acne, hair growth on the body and face, as well as male pattern baldness.
Hair loss is not expressed at all in all. Worrying about what should first those who have a genetic predisposition (the case of baldness in the family). To prevent this side effect, the drug may be used Propecia (Proscar), which blocks the conversion of testosterone to dihydrotestosterone. Propecia significantly reduces the risk of alopecia, and reduces the probability of remaining androgenic effects.
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The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.