DHT, or dihydrotestosterone, is a hormone that is involved in the development of male characteristics, such as facial hair and a deep voice. It is also thought to play a role in hair loss, particularly in men with male pattern baldness. DHT is produced when testosterone is converted by an enzyme called 5-alpha reductase. In people with male pattern baldness, DHT is believed to cause hair loss by shrinking the hair follicles, which leads to thinning of the hair and eventual hair loss. There are medications that can block the production of DHT or inhibit its effects on the hair follicles, which may help to slow or prevent hair loss. However, more research is needed to fully understand the role of DHT in hair loss and the best ways to address it.