Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
Side effects are minimized by taking the lowest doses possible (that still yields positive results) and following doctor's orders. It is important to avoid self-regulation of the dosage, either by adding more or stopping the drug without a schedule. After prolonged use, steroids must be gradually reduced to permit the adrenal glands to resume natural cortisol production. Eliminating doses too quickly can result in glucocorticoid withdrawal symptoms, worsening of underlying inflammatory disease (rebound effect), or rarely, adrenal crisis (a life-threatening state caused by insufficient levels of adrenal steroids).
In the United States, supplements such as tetrahydrogestrinone (THG) and androstenedione (street name "Andro") previously could be purchased legally without a prescription through many commercial sources, including health food stores. Steroidal supplements can be converted into testosterone or a similar compound in the body. Less is known about the side effects of steroidal supplements, but if large quantities of these compounds substantially increase testosterone levels in the body, then they also are likely to produce the same side effects as anabolic steroids themselves. The purchase of these supplements, with the notable exception of dehydroepiandrosterone (DHEA), became illegal after the passage in 2004 of amendments to the Controlled Substances Act.