Testosterone is a steroid sex hormone found in both men and women. In men, testosterone is produced primarily by the Leydig (interstitial) cells of the testes when stimulated by luteinizing hormone (LH). It functions to stimulate spermatogenesis, promote physical and functional maturation of spermatozoa, maintain accessory organs of the male reproductive tract, support development of secondary sexual characteristics, stimulate growth and metabolism throughout the body and influence brain development by stimulating sexual behaviors and sexual drive. In women, testosterone is produced by the ovaries (25%), adrenals (25%) and via peripheral conversion from androstenedione (50%). Testerone in women functions to maintain libido and general wellbeing. Testosterone exerts a negative feedback mechanism on pituitary release of LH and follicle-stimulating hormone (FSH). Testosterone may be further converted to dihydrotestosterone or estradiol depending on the tissue. The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. Testosterone is used as hormone replacement or substitution of diminished or absent endogenous testosterone. Use in males: For management of congenital or acquired hypogonadism, hypogonadism associated with HIV infection, and male climacteric (andopause). Use in females: For palliative treatment of androgen-responsive, advanced, inoperable, metastatis (skeletal) carcinoma of the breast in women who are 1-5 years postmenopausal; testosterone esters may be used in combination with estrogens in the management of moderate to severe vasomotor symptoms associated with menopause in women who do not respond to adequately to estrogen therapy alone.

Testosterone is a steroid sex hormone found in both men and women. In men, testosterone is produced primarily by the Leydig (interstitial) cells of the testes when stimulated by luteinizing hormone (LH). It functions to stimulate spermatogenesis, promote physical and functional maturation of spermatozoa, maintain accessory organs of the male reproductive tract, support development of secondary sexual characteristics, stimulate growth and metabolism throughout the body and influence brain development by stimulating sexual behaviors and sexual drive. In women, testosterone is produced by the ovaries (25%), adrenals (25%) and via peripheral conversion from androstenedione (50%). Testerone in women functions to maintain libido and general wellbeing. Testosterone exerts a negative feedback mechanism on pituitary release of LH and follicle-stimulating hormone (FSH). Testosterone may be further converted to dihydrotestosterone or estradiol depending on the tissue. The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. Testosterone is used as hormone replacement or substitution of diminished or absent endogenous testosterone. Use in males: For management of congenital or acquired hypogonadism, hypogonadism associated with HIV infection, and male climacteric (andopause). Use in females: For palliative treatment of androgen-responsive, advanced, inoperable, metastatis (skeletal) carcinoma of the breast in women who are 1-5 years postmenopausal; testosterone esters may be used in combination with estrogens in the management of moderate to severe vasomotor symptoms associated with menopause in women who do not respond to adequately to estrogen therapy alone.

STANOLONE, also known as dihydrotestosterone, is a potent androgenic metabolite of testosterone and anabolic agent for systemic use. It may be used as a replacement of male sex steroids in men who have androgen deficiency, for example as a result of the loss of both testes, and also the treatment of certain rare forms of aplastic anemia which are or may be responsive to anabolic androgens.

Methenolone (also known as primobolan) was described in 1960. Squibb Company began producing injectable drug in 1962. Methenolone originally was prescribed in case of muscle loss after operations, infections, long-term illnesses, aggressive therapy with corticoids or malnutrition, and in some cases it was used to treat osteoporosis and breast cancer. Methenolone was commonly used to promote weight gain in infants, weighing less than normal, without any side effects. Methenolone is an anabolic steroid, modification of dihydrotestosterone (DHT) with weak androgenic activity and a moderate anabolic effect. A notable trait of methenolone is that it can firmly bind to androgen receptors, stronger than testosterone. Adult doses for the treatment of aplastic anemia are usually in a range of 1–3 mg/kg per day. Adverse side effects include fluid and electrolyte retention, hypercalcaemia, increased bone growth and skeletal weight. In men, additional side priapism, azoospermia, hirsutism, male pattern baldness, acne andoedema. In women, side effects include virilization, amenorrhoea, menstrual irregularities, suppressed lactation, and increased libido. In children, side effects may include virilization symptoms. Metenolone may enhance effects of antidiabetics, ciclosporin, levothyroxine, warfarin. Resistance to the effects of neuromuscular blockers may occur, and metenolone also has the potential to interfere with glucose tolerance and thyroidfunction tests. Metenolone enanthate (methenolone enanthate) is an ester derivative of methenolone sold commonly under the brand names Primobolan (tablet form) orPrimobolan Depot (injectable). When it interacts with the aromatase enzyme it does not form any estrogens. It is used by people who are very susceptible to estrogenic side effects, having lowerestrogenic properties than nandrolone. This trait makes primobolan to be a good fat burner. Primobolan does not convert into estradiol. As an anabolic steroid, the use of metenolone is banned from use in sports governed by the World Anti-Doping Agency. Belarusian shot putter Nadzeya Ostapchuk was stripped of her gold medal after testing positive for metenolone at the London 2012 Olympic Games. She has been excluded from future IOC events. The NBA and NBPA also banned the use of methenolone under the Anti-Drug Program. In February 2013, Hedo Türkoğlu of the Orlando Magic was suspended for 20 games without pay by the league after testing positive for methenolone. In December 2013, Natalia Volgina was stripped of her 2013 Old Mutual Two Oceans Marathon title and received a two-year competition ban, subsequent to a final guilty verdict for using the steroid Metenolone.