"Anabolic-androgenic steroids" is the medical term for the drugs that some athletes use illegally in an attempt to gain an unfair advantage over their opponents. Examples include:

• Testosterone
• Methyltestosterone
• Androstenedione
• Danazol 

Using performance-enhancing steroids like testosterone is sometimes called "doping" or "juicing."

Both males and females normally have testosterone circulating in their bodies, although the amount in males is much higher. Testosterone works to promote the appearance of male secondary sexual characteristics, such as a deepening voice and the growth of body and facial hair. It also has effects on muscles and bones.

Performance-enhancing steroids usually work by mimicking natural testosterone.  Reported effects of steroid use include an increase in muscle size, strength, and fat-free body mass, all of which are thought to improve athletic performance.

Performance-enhancing steroids are drugs that have both physical and mental side effects. Athletes who use them can become sick or seriously injured. 

Physical Side Effects

Common physical side effects of steroid use include:

• Acne or pimples
• Scars or stretch marks
• Premature hair loss in males
• Deepened voice in females
• Excessive growth of body and facial hair in females

Additionally, athletes who use a needle to inject steroids may have pain at the injection site and risk developing an infection.

Steroid use can also affect sexual development and performance by causing:

• Irregular periods
• Breast enlargement in both males and females
• Shrinking of the testicles
• Erectile dysfunction and infertility

Mental Side Effects

Steroid users may become overly aggressive or combative, a condition commonly referred to as "'roid rage." Uncontrolled aggression causes some steroid users to become confrontational with friends and family; sometimes, they end up in trouble with the law.

Depression has also been linked to steroid use, and athletes who use performance-enhancing steroids are more likely to attempt suicide than athletes who do not use them.

Health Risks

While some side effects of steroids may be just a nuisance, others may be life-threatening. For example, using steroids has been associated with:

• Liver problems
• Heart problems
• Accidente cerebrovascular
• Coágulos sanguíneos
• Cáncer

Parents and coaches should help young athletes understand that they can excel in sports without using steroids. Alternatives for meeting fitness and performance goals include eating a proper diet, getting enough sleep, and having good overall mental and physical health.