All bets are off the table when high-dose testosterone and its many metabolites are used illegally, such as with anabolic steroid abuse. Strokes, embolisms, and cardiovascular disease are all more likely, as is sudden death, and liver and kidney disease. 44 In women, acne, irreversible deepening of the voice, baldness, increased facial hair, enlarged sex organs, breast reduction, depression, and infertility have all been reported. In adult men that abuse anabolic steroids, acne, baldness, permanent infertility, gynecomastia, loss of libido, erectile dysfunction, testicle shrinkage, and profuse sweating are all reported side effects. Increased testicular cancer hasn't been reported, though. 45,46
The side effects of Nebido can include those of an androgenic nature. The androgenic side effects of Nebido are, however, highly dependent on genetic predispositions and will not affect all men. The possible androgenic side effects of Nebido include accelerated hair loss in those predisposed to male pattern baldness, acne in sensitive individuals and body hair growth.
While by no means always necessary, some men may find the use of a 5-alpha reductase inhibitor to be useful. The testosterone hormone is metabolized by the 5-alpha reductase enzyme, which reduces the testosterone hormone to dihydrotestosterone (DHT). The DHT is what leads to the androgenic related effects. By incorporating a 5-alpha reductase inhibitor, you will reduce the hormones androgenicity. It will not be a complete reduction, but it will be significant. However, such inhibitors are not always recommended and should only be used as needed as they can hinder the potency of the testosterone hormone.