It will massively elevate your testosterone levels while shutting down your testicles' endogenous production of testosterone. It'll make your feel hornier, and you'll be super-capable of all normal sexual functions, but your sperm production will gradually decrease (and your testicle volume will shrink) to the point of infertility (despite continuing to feel and act very horny). Sperm production, testicle volume and fertility will return to normal after discontinuation.
Dianabol is a 17-alpha alkylated steroid, which means that it is much more likely to produce liver toxicity. See the link below for a fairly balanced research article on anabolic steroids.
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