Hormone therapy or hormonal therapy is the use of hormones in medical treatment. Gender-affirming hormones are used to alter someone's physical appearance to more closely align their physical body with their gender identity. Testosterone therapy is used to suppress female secondary sex characteristics and masculinize transgender men. Feminizing hormone therapy typically is used by transgender women and nonbinary people to produce physical changes in the body that are caused by female hormones during puberty. Those changes are called secondary sex characteristics.