What are steroidal supplements? In the United States, supplements such as dehydroepian-drosterone (DHEA) and androstenedione (street name Andro) can be purchased legally without a prescription through many commercial sources including health food stores. They are often referred to as dietary supplements, although they are not food products. They are often taken because the user believes they have anabolic effects. Steroidal supplements can be converted into testosterone (an important male sex hormone) or a similar compound in the body. Whether such conversion produces sufficient quantities of testosterone to promote muscle growth or whether the supplements themselves promote muscle growth is unknown. Little is known about the side effects of steroidal supplements, but if large quantities of these compounds substantially increase testosterone levels in the body, they also are likely to produce the same side effects as anabolic steroids.