A Review of Gender-Affirming Hormone Therapy for Transgender and Gender Diverse Adults in South Korea.

Recently, gender-affirming hormone therapy for gender incongruence has become an issue in various countries and organizations with various guidelines. In South Korea, several clinical treatments are also used with many possible options. These treatments include masculinizing (female-to-male [FTM]) or feminizing (male-to-female [MTF]) hormone therapies, with regimens usually driven by standards of hormonal replacement therapy for hypogonadism (i.e., hypogonadal natal men and postmenopausal women). This cross-sex hormone therapy can change patients' physical appearance to better match their gender identity and expression. Regarding masculinizing therapy, injection and transdermal gel types of testosterone are used according to international guidelines. Progesterone is utilized in the form of oral pills, injections, or intrauterine devices to suppress menstruation and avoid pregnancy. Essentially, feminizing therapy uses androgen blockers along with estrogen. This is because estrogen alone cannot exert sufficient androgen-suppressing effects. In South Korea, the most commonly used androgen blockers are spironolactone and cyproterone acetate. Gonadotropin-releasing hormone (GnRH) agonist is also available. Regarding estrogen, oral pills, injections, and transdermal gels are utilized. This review introduces these gender-affirming hormone therapies in South Korea and discusses the side effects of each regimen.