Oxymetholone, sold under the brand names Anadrol and Anapolon among others, is an androgen and anabolic steroid (AAS) medication which is used primarily in the treatment of anemia. It is also used to treat osteoporosis, HIV/AIDS wasting syndrome, and to promote weight gain and muscle growth in certain situations. Like other AAS, oxymetholone is an agonist of the androgen receptor (AR). It is not a substrate for 5α-reductase (as it is already 5α-reduced) and is a poor substrate for 3α-hydroxysteroid dehydrogenase (3α-HSD), and therefore shows a high ratio of anabolic to androgenic activity.