When athletes or their parents hear the word ‘steroid,’ they may envision a muscle-building, performance-enhancing drug that not only destroys the integrity of sport, but also comes with extreme health risks – especially for young athletes.

When it comes to steroids, however, that description is only one piece of the equation. There are actually multiple classes of steroids, including anabolic steroids and corticosteroids, which have different uses, side effects, and performance-enhancing qualities.

Amy Eichner, PhD, U.S. Anti-Doping Agency’s Special Advisor on Drug Reference and Supplements, explains five things you need to know about steroids, including the difference between corticosteroids and anabolic steroids.

What are steroids?

Steroids are a class of compounds that all have a similar structure and bind to hormone receptors in the body. Anabolic steroids bind to the androgen receptors, whereas corticosteroids bind to the glucocorticoid receptors – leading to different effects on the body.

The body naturally produces testosterone, an anabolic steroid, that regulates bone and muscle mass and fat distribution, as well as sex-drive (libido) and red blood cell production. The body also naturally produces cortisol, a corticosteroid. When cortisol binds to the glucocorticosteroid receptor, it activates a metabolic pathway that suppresses inflammation and immune responses.

There are also many synthetically produced anabolic and corticosteroid compounds, some of which are legitimate medicines and some of which are not.

What are they used for?

Prescription use of testosterone can be used to treat hypogonadism in men, or to prevent the loss of muscle associated with HIV infection. In some teenage boys that have been diagnosed with delayed onset of puberty or a genetic abnormality, testosterone injections are sometimes prescribed to kick-start growth and development.

Corticoids are often prescribed to reduce inflammation and allergic reactions. Corticosteroid creams can be applied to the skin to treat poison ivy rashes, or contact dermatitis, whereas corticosteroids in pill form can be taken to treat allergies, as well as autoimmune disorders like lupus or rheumatoid arthritis. Inhaled corticosteroids are effective in treating asthma, and corticosteroid injections into joints can treat inflammation related to sport injuries or arthritis.

Are there side effects with steroid use?