It seems that most anabolic steroids normally work by activating the human androgen receptors, producing anabolic and virilizing effects.
Here you have some examples of anabolic effects:
- Elevated protein synthesis from amino acids
- Increased muscle mass and strength
- Increased appetite
- Increased bone remodeling and growth
- Stimulation of bone marrow increasing production of red blood cells
Some examples of virilizing effects, normally associated to side effects:
- Growth of the clitoris (clitoral hypertrophy) in females and the penis in male children (the adult penis does not grow indefinitely even when exposed to high doses of androgens)
- Increased growth of androgen-sensitive hair (pubic, beard, chest, and limb hair)
- Increased vocal cord size, deepening the voice
- Increased libido
- Suppression of endogenous sex hormones
- Impaired spermatogenesis
Many androgens are metabolized to compounds which also cross-react with estrogen receptors, producing additional (usually) unwanted effects:
- Accelerated bone maturation in children
- Increased breast growth (in males)