Intake of anabolic steroids and strength-training induce an increase in muscle size by both hypertrophy and the formation of new muscle fibers. We propose that activation of satellite cells is a key process and is enhanced by the steroid use. The incorporation of the satellite cells into preexisting fibers to maintain a constant nuclear to cytoplasmic ratio seems to be a fundamental mechanism for muscle fiber growth. Although all the subjects in this study have the same level of performance, the possibility of genetic differences between the two groups cannot be completely excluded.
As a non-aromatizing androgen, dihydrotestosterone is extremely potent. Aromatization refers to the conversion of testosterone or anabolic steroids into estrogen. High estrogenic activity causes bloating, acne, water retention and oily skin. As dihydrotestosterone does not aromatize even at high dosages, users do not face the aforementioned side-effects. Lack of water retention also has a hardening effect on muscle tissue, in bodybuilders. Being a powerful androgen, dihydrotestosterone is also responsible for a shift in the estrogen-testosterone ratio in the body. Due to its predominant androgenic component, the steroid has a stimulating effect on the adreno-pituitary functions, and causes neurological excitation in the ‘sexual orientation areas of the brain’. This in turn, spikes sex drive in males.