Methyltestosterone is an anabolic steroid hormone used to treat men with a testosterone deficiency. It is also used in women to treat breast cancer, breast pain, swelling due to pregnancy, and with the addition of estrogen it can treat symptoms of menopause. 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. Methyltestosterone is marketed under the brand names Android, Androral, Metandren, Oraviron, Testred, Virilon.

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.

Clostebol is a synthetic anabolic-androgenic steroid, a derivative of the natural hormone testosterone. Clostebol is a Schedule III controlled substance used medically in topical ophthalmologic and dermatologic treatments. Due to potential use as a performance-enhancing drug, clostebol is banned by the World Anti-Doping Agency.

Adrenosterone (androst-4-ene-3,11,17-trione, 11-oxoandrostenedione) is an endogenous steroid hormone that has been promoted as a dietary supplement capable of reducing body fat and increasing muscle mass. Adrenosterone has shown to be converted into 11-ketotestosterone in humans, which contributes to adrenosterone's androgenic effects. It is proposed that adrenosterone may function as an inhibitor of the 11beta-hydroxysteroid dehydrogenase type 1 enzyme (11beta-HSD1), which is primarily responsible for reactivation of cortisol from cortisone.

Metandienone is an orally active synthetic anabolic-androgenic steroid. In 1970, the FDA accepted that Metandienone (Dianabol) was “Probably Effective” in treating post-menopausal osteoporosis and pituitary-deficient dwarfism. Methandrostenolone is still produced today, but typically in nations with loose prescription drug regulations and by companies that still prefer to cater to an underground athletic market. Androgenic side effects are still common with this substance. This may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss.

Fluoxymesterone, sold under the brand names Halotestin and Ultandren among others, is a synthetic, orally active androgenic-anabolic steroid (AAS) and a 17α-alkylated derivative of testosterone developed by Pharmacia & Upjohn Company LLC, approved by FDA at 1956. Fluoxymesterone is used in the treatment of hypogonadism in males and breast cancer in women. Fluoxymesterone has a relatively high ratio of androgenic to anabolic activity similarly to testosterone. Like many 17α-alkylated AAS, it has a relatively low affinity for the androgen receptor (AR). However, its actions are mediated by the AR, most likely due to its relatively long elimination half-life of approximately 9.2 hours.

Boldenone (INN, BAN), also known as Δ1-testosterone, 1-dihydrotestosterone, or androsta-1,4-dien-3-one-17β-ol (train name Equipoise) is a long-acting injectable anabolic agent for horses, supplied in a vial providing 50 mg boldenone undecylenate per mL in sesame oil with 3% (w/v) benzyl alcohol as a preservative. The activity of boldenone is mainly anabolic, with a low androgenic potency. Boldenone will increase nitrogen retention, protein synthesis increases appetite and stimulates the release of erythropoietin in the kidneys. Boldenone was synthesized in an attempt to create a long-acting injectable methandrostenolone (Dianabol), for androgen deficiency disorders. Boldenone acts similar to methandrostenolone with fewer adverse androgenic effects. Although commonly compared to nandrolone, boldenone lacks progesterone receptor interaction and all the associated progestogenic side effects. Equipoise (Boldenone Undecylenate Injection) is recommended as an aid for treating debilitated horses when an improvement in weight, haircoat or general physical condition is desired. Debilitation often follows disease or may occur following overwork and overexertion. Boldenone improves the general state of debilitated horses, thus aiding in correcting weight losses and improving appetite. It is not a substitute for a well-balanced diet. Optimal results can be expected only when good management and feeding practices are utilized. Boldenone should be considered only as adjunctive therapy to other specific and supportive therapy for diseases, surgical cases, and traumatic injuries.