Flutamide and 2-hydroxyflutamide have been found in vitro to inhibit CYP17A1 (17α-hydroxylase/17,20-lyase), an enzyme which is required for the biosynthesis of androgens.  In accordance, flutamide has been found to slightly but significantly lower androgen levels in GnRH analogue-treated male prostate cancer patients  and women with polycystic ovary syndrome .  As such, flutamide is a weak inhibitor of androgen biosynthesis.  However, the clinical significance of this action may be limited when flutamide is given without a GnRH analogue to non-castrated men, as the drug markedly elevates testosterone levels into the high normal male range via prevention of AR activation-mediated negative feedback on the hypothalamic–pituitary–gonadal axis in this context. 
Despite all positive effects of doping on the body they could be dangerous. Possible side effects of anabolic steroids can be avoided by choosing the right form (oral or injectable) and combination as well as by taking reasonable androgenic dosages. It has to be mentioned, that the most side effects of drugs disappear after the cycle is completed. Moreover, many of them can be blocked during the cycle by using respective supplements. Therefore, in order to avoid possible negative consequences one shall pay attention to studying information about the drugs prior to use them.