Androgens
Testosterone and related steroids. They replace testosterone in male hypogonadism; weak androgens such as danazol suppress the pituitary-ovarian axis.
What they are
Testosterone (injectable esters, gels, patches, oral undecanoate) and synthetic derivatives that act on the androgen receptor. Testosterone replaces the hormone in men with primary or hypogonadotropic hypogonadism and induces puberty in delayed puberty. Danazol, a weak androgen and antigonadotropin, is used for endometriosis and to prevent attacks of hereditary angioedema. Anabolic-androgenic steroids are also misused to build muscle.
Mechanism of action
Androgens bind the androgen receptor, a nuclear receptor, directly or after conversion of testosterone to dihydrotestosterone by 5-α-reductase; some testosterone is aromatised to estradiol. The receptor complex switches genes that develop and maintain male sexual characteristics, spermatogenesis, muscle, bone and erythropoiesis. Exogenous androgens also suppress LH and FSH, which lowers sperm production.
Target: Androgen receptor (AR), a nuclear receptor
Drugs in this class
- TestosteroneThe main male sex hormone, given as injections, gels or patches to replace testosterone in men whose testes or…Androgen receptor (AR), a nuclear receptor
- DanazolA synthetic weak androgen that suppresses the pituitary-ovarian axis. Used for endometriosis and to prevent hereditary…Androgen and other gonadal steroid receptors; it suppresses pituitary FSH and LH
Others in the class
- Methyltestosterone
- Fluoxymesterone
- Oxandrolone
- Nandrolone
Test yourself
Think of the answer, then tap the question to see it.
Why does testosterone therapy lower sperm count?
Exogenous testosterone suppresses pituitary LH and FSH by negative feedback, so the testes produce less sperm.
Which blood test rises with testosterone and must be monitored?
Haemoglobin and haematocrit (erythrocytosis), which increase the risk of thrombosis.
Which two cancers contraindicate testosterone in men?
Breast cancer and known or suspected prostate cancer.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - TESTOSTERONE CYPIONATE injection (DailyMed (U.S. National Library of Medicine), 2026); Testosterone Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); DailyMed - DANAZOL capsule (DailyMed (U.S. National Library of Medicine), 2026).
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Representative model, for educational purposes only.