Male hormones

Related Terms

Anabolic steroids, Anabolic Steroids Act (ASA), blood doping, controlled substances, Controlled Substances Act (CSA) cycling, hormone therapy, hormone replacement, illegal drugs, male hormones, prohormones, schedule III, steroids, stacking, testosterone.


Testosterone enhancement is the illegal use of anabolic steroids to boost athletic performance. Anabolic steroids are male sex hormones, collectively known as androgens. Although illegal, these hormones are frequently taken by athletes to build more muscle and endurance than would be impossible to produce through legal ergogenic aids or training. The most popular and well-known anabolic steroid is testosterone, a synthetic chemical that imitates the effects of naturally produced human male hormones.
Physicians began prescribing anabolic steroids for a number of legitimated medical purposes in the 1940s. Athletes quickly began using anabolic steroids for another purpose: to boost their athletic performance. In 1991, Congress placed anabolic steroids as a class of drugs into the Schedule III of the Controlled Substances Act (CSA). This legislation was signed into law after years of concern over a growing illicit market, abuse by teenagers, and the uncertainty of possible harmful long-term effects of steroid use. The CSA defines anabolic steroids as any drug or hormonal substance chemically and pharmacologically related to testosterone (other than estrogens, progestins, and corticosteroids) that promotes muscle growth. Prohormones, precursors of testosterone, are also classified as controlled substances as of the Anabolic Steroids Act of 2004. Their use to boost athletic performance is also illegal.
Anabolic steroids offer athletes an unfair advantage and are banned by all major sporting organizations. Athletes are regularly screened for such illegal methods in professional sports and the Olympics. The use of illegal ergogenic aids also occurs at high school levels. Organizations such as the National Collegiate Athletic Association (NCAA) have initiated extensive public outreach campaigns to educate and dissuade athletes from using steroids or blood doping.
In recent years, physicians have prescribed anabolic steroids to maintain muscle mass in AIDS patients, to induce male puberty, and to assist in the transition of female to male transgendered individuals diagnosed with gender dysmorphia. In all cases, anabolic steroids are prescribed only after trying other classes of medications. The use of anabolic steroids for a use other than that prescribed to a patient is strictly illegal in the United States.

Theory / Evidence

Anabolic steroids work in two ways simultaneously. First, the steroids increase the synthesis of testosterone in the body while simultaneously blocking the receptor that inactivates the hormones. Secondly, anabolic steroids block the effects of cortisol, a stress hormone, on muscle tissue. As a result, individuals who take anabolic steroids experience a variety of effects. The body's muscle mass and strength increases at an abnormally high rate. The rate of protein synthesis is elevated. Bone remodeling and growth occur much faster than before. Bone marrow is stimulated to produce more red blood cells.
Until the passage of the Anabolic Steroids Act of 2004, many athletes used prohormones (which were legal then) as an alternative to anabolic steroids. The precursors to actual hormones, prohormones caused similar, although less drastic results as taking steroids. Prohormones are now classified as a controlled substance, and are illegal for the purpose of athletic performance enhancement.
The human body goes through five steps to produce hormones. The ingestion or injection of prohormones skips at least one of these five steps, and thus increases the body's production of testosterone.
Although clinical studies have shown the effectiveness of anabolic steroids for certain medical conditions and testosterone enhancement, the number of potential side effects is quite large. Regardless of the efficacy of this practice, the use of anabolic steroids for a use other than that prescribed to a patient is illegal in the United States.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (


Calfee R, Fadale P. Popular ergogenic drugs and supplements in young athletes. Pediatrics. 2006 Mar;117(3):e577-89. .
FDA News. 1 June 2006.
National Collegiate Athletic Association. 8 June 2006.
National Institutes on Drug Abuse InfoFacts. 1 June 2006.
National Institutes of Health. 1 June 2006.
United States Department of Justice. 8 June 2006.


Testosterone and anabolic steroids are taken orally, or they may be self-injected. Often, athletes take multiple anabolic steroids simultaneously, according to one of two methods, cycling or stacking. Both of these methods are considered equally dangerous.
Cycling: Athletes take multiple types of high dose steroids simultaneously in cycles of weeks or months, and then abstain from their use for a wash out period before beginning the cycle again. This pattern is thought to maximize the benefits of the steroids by preventing the body from adjusting to, and thus weakening the effects of the drugs.
Stacking: Individuals take multiple brands or types of anabolic steroids simultaneously in the belief that such a dosing pattern will have more of an effect than any one drug taken individually. While this pattern is thought to reduce the short-time side effects of anabolic steroid abuse, it does not in any way minimize the often irreversible long-term side effects.
  • Some individuals turn to other drugs to counteract the immediate side effects of steroids (e.g. irritability or acne). Such use may result in further medical complications or multiple addictions.
  • It is illegal to bring anabolic steroids, including testosterone, into the United States with the intent to use the drugs to boost athletic performance or to distribute to athletes.