Some athletes take a form of steroids — known as anabolic steroids — to increase their muscle mass and strength. The main anabolic steroid hormone produced by your body is testosterone.

Testosterone has two main effects on your body:

- Anabolic effects promote muscle building.

- Androgenic effects are responsible for male traits, such as facial hair and a deeper voice.

The anabolic steroids that athletes use are synthetic modifications of testosterone. These drugs were developed in an attempt to maximize the anabolic effects and minimize the androgenic effects of testosterone. As it turns out, these two actions of testosterone can't be separated.

Given by pill, injection or topical treatment, these hormones have many medical uses. Some of these include replacement therapy for men deficient in testosterone, helping people with AIDS maintain muscle mass and reduce muscle wasting, and treating rare types of anemia.

Why are these drugs so appealing to athletes? Besides making muscles bigger, anabolic steroids may help athletes recover from a hard workout more quickly by reducing the amount of muscle damage that occurs during the session. In addition, some athletes may like the aggressive feelings they get when they take the drugs.

However, many athletes take anabolic steroids at doses that are much higher than those prescribed for medical reasons. The effects of taking anabolic steroids at very high doses haven't been well studied.

Anabolic steroids come with serious side effects.

Men may develop:

- Prominent breasts

- Baldness

- Shrunken testicles

- A higher voice

- Infertility

Women may develop:

- A deeper voice

- An enlarged clitoris

- Increased body hair

- Baldness

- Increased appetite

Both men and women might experience:

- Severe acne

- Liver abnormalities and tumors

- Increased low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol)

- Decreased high-density lipoprotein (HDL) cholesterol (the "good" cholesterol)

- Aggressive behaviors, rage or violence

- Psychiatric disorders, such as depression

- Drug dependence

If an injected form is used, you'll face a higher risk of infections and diseases that are transmitted in blood, such as HIV and hepatitis. And in teens, steroids can halt their normal pattern of growth and development and put them at risk of future health problems.

Anabolic steroids aren't legal substances, unless your doctor has prescribed them for medical reasons. Taking anabolic steroids to enhance athletic performance, besides being prohibited by most sports organizations, is illegal.

One anabolic steroid receivng a lot of attention is tetrahydrogestrinone (THG). Until recently, THG was marketed as a dietary supplement for enhancing athletic performance. However, researchers have found that THG is actually a chemically altered version of an anabolic steroid that is banned by most sports organizations. THG is referred to as a "designer" steroid because it's undetectable by traditional steroid testing techniques. A new laboratory test, however, now makes its detection possible. The Food and Drug Administration (FDA) warns that athletes taking THG may be putting their health at risk — THG is an unapproved new drug and little is known about its safety.

Other common anabolic steroids include dehydrochlormethyltestosterone (Turinabol), metandienone (Dianabol), methyltestosterone (Android), nandrolone (Durabolin), oxandrolone (Oxandrin), oxymetholone (Anadrol) and stanozolol (Winstrol).