Anabolic steroids are a class of natural and synthetic steroid hormones that promote cell growth and division, resulting in growth of muscle tissue and sometimes bone size and strength. Testosterone is the best known natural anabolic steroid, as well as the best known natural androgen.
Most anabolic steroids work by activation of androgen receptors, producing anabolic and virilizing effects.
Examples of anabolic effects:
* Increased protein synthesis from amino acids
* Increased muscle mass and strength
* Increased appetite
* Increased bone remodelling and growth
* Stimulation of bone marrow increasing production of red blood cells
Examples of virilizing effects:
*Growth of the clitoris 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
*Suppression of endogenous sex hormones
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)
A hormone with purely anabolic effects would have many uses, but in many cases the usefulness is limited by unwanted virilizing effects.
Many of the synthetic anabolic steroids were devised in an attempt to find molecules that produced a higher degree of anabolic rather than virilizing effects.
Other side effects (some the opposite of intended effects) include elevated blood pressure and cholesterol levels, severe acne, premature baldness, reduced sexual function, and testicular atrophy. In males, abnormal breast development (gynecomastia) can occur. In females, anabolic steroids have a masculinizing effect, resulting in more body hair, a deeper voice, smaller breasts, masculinized or enlarged clitoris, and fewer menstrual cycles. Several of these effects are irreversible. In adolescents, abuse of these...