Hair Glossary

Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from releasing their biological effects in the body

They act by blocking the androgen receptor (AR) and/or inhibiting or suppressing androgen production

Androgen  Agonists
They can be thought of as the functional opposites of androgen receptor (AR) agonists, for instance, androgens and anabolic steroids (AAS) like testosterone, DHT, and nandrolone.  Also, selective androgen receptor modulators (SARMs) like enobosarm

Antiandrogens are one of three types of sex hormone antagonists, the others being antiestrogens and antiprogestogens

Antiandrogens are used to treat an assortment of androgen-dependent conditions

In men, antiandrogens are used in the treatment of prostate cancer, enlarged prostate, scalp hair loss, overly high sex drive, unusual and problematic sexual urges, and early puberty

In women, antiandrogens are used to treat acne, seborrhea, excessive hair growth, scalp hair loss, and high androgen levels, such as those that occur in polycystic ovary syndrome (PCOS)

Antiandrogens are also used as a component of feminizing hormone therapy for transgender women and as puberty blockers in transgender girls

Side effects of antiandrogens depend on the type of antiandrogen and the specific antiandrogen in question

In any case, common side effects of antiandrogens in men include breast tenderness, breast enlargement, feminization, hot flashes, sexual dysfunction, infertility, and osteoporosis. In women, antiandrogens are much better tolerated, and antiandrogens that work only by directly blocking androgens are associated with minimal side effects

Because estrogens are made from androgens in the body, antiandrogens that suppress androgen production can cause low estrogen levels and associated symptoms like hot flashes, menstrual irregularities, and osteoporosis in premenopausal women

There are different major types of antiandrogens.
AR antagonists - AR antagonists work by directly blocking the effects of androgens

AR antagonists can be further divided into steroidal antiandrogens and nonsteroidal antiandrogens

androgen synthesis inhibitors - androgen synthesis inhibitors lower androgen levels

Androgen synthesis inhibitors can be further divided mostly into CYP17A1 inhibitors and 5α-reductase inhibitors

antigonadotropins - antigonadotropins work by lowering androgen levels

Antigonadotropins can be further divided into gonadotropin-releasing hormone modulators (GnRH modulators), progestogens, and estrogens

Antiandrogens Are Used In The Treatment Of Androgen-Dependent Conditions
Antiandrogens are used in the treatment of an assortment of androgen-dependent conditions in both males and females. 
They are used to treat men with prostate cancer, benign prostatic hyperplasia, pattern hair loss, hypersexuality, paraphilias, and priapism, as well as boys with precocious puberty

In women and girls, antiandrogens are used to treat acne, seborrhea, hidradenitis suppurativa, hirsutism, and hyperandrogenism

Antiandrogens are also used in transgender women as a component of feminizing hormone therapy and as puberty blockers in transgender girls.