Are you hoping to gain a competitive edge by taking muscle-building supplements or other performance-enhancing drugs? Learn how these drugs work and how they can affect your health. By Mayo Clinic Staff

Most serious athletes will tell you that the competitive drive to win can be fierce. Besides the satisfaction of personal accomplishment, athletes often pursue dreams of winning a medal for their country or securing a spot on a professional team. In such an environment, the use of performance-enhancing drugs has become increasingly common.

But using performance-enhancing drugs — aka, doping — isn't without risks. Take the time to learn about the potential benefits, the health risks and the many unknowns regarding so-called performance-enhancing drugs such as anabolic steroids, androstenedione, human growth hormone, erythropoietin, diuretics, creatine and stimulants. You may decide that the benefits aren't worth the risks.

What are they?
Some athletes take a form of steroids — known as anabolic-androgen steroids or just 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.

Some athletes take straight testosterone to boost their performance. Frequently, the anabolic steroids that athletes use are synthetic modifications of testosterone. These hormones have approved medical uses, though improving athletic performance is not one of them. They can be taken as pills, injections or topical treatments.

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 muscle damage that occurs during the session. This enables athletes to work out harder and more frequently without overtraining. In addition, some athletes may like the aggressive feelings they get when they take the drugs.

Designer steroids
A particularly dangerous class of anabolic steroids are the so-called designer drugs — synthetic steroids that have been illicitly created to be undetectable by current drug tests. They are made specifically for athletes and have no approved medical use. Because of this, they haven't been tested or approved by the Food and Drug Administration (FDA) and represent a particular health threat to athletes.

Risks
Many athletes take anabolic steroids at doses that are much higher than those prescribed for medical reasons, and most of what is known about the drugs' effects on athletes comes from observing users. It is impossible for researchers to design studies that would accurately test the effects of large doses of steroids on athletes, because giving participants such high doses would be unethical. This means that the effects of taking anabolic steroids at very high doses haven't been well studied.

Anabolic steroids come with serious physical side effects as well.

Men may develop:

  • Prominent breasts
  • Baldness
  • Shrunken testicles
  • Infertility
  • Impotence

Women may develop:

  • A deeper voice
  • An enlarged clitoris
  • Increased body hair
  • Baldness
  • Infrequent or absent periods

Both men and women might experience:

  • Severe acne
  • Increased risk of tendinitis and tendon rupture
  • Liver abnormalities and tumors
  • Increased low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol)
  • Decreased high-density lipoprotein (HDL) cholesterol (the "good" cholesterol)
  • High blood pressure (hypertension)
  • Heart and circulatory problems
  • Prostate gland enlargement
  • Aggressive behaviors, rage or violence
  • Psychiatric disorders, such as depression
  • Drug dependence
  • Infections or diseases such as HIV or hepatitis if you're injecting the drugs
  • Inhibited growth and development, and risk of future health problems in teenagers

Taking anabolic-androgenic steroids to enhance athletic performance, besides being prohibited by most sports organizations, is illegal. In the past 20 years, more effective law enforcement in the United States has pushed much of the illegal steroid industry into the black market. This poses additional health risks because the drugs are either made in other countries and smuggled in or made in clandestine labs in the United States. Either way, they aren't subject to government safety standards and could be impure or mislabeled.

What is it?
Androstenedione (andro) is a hormone produced by the adrenal glands, ovaries and testes. It's a hormone that's normally converted to testosterone and estradiol in both men and women.

Andro is available legally only in prescription form, and is a controlled substance. Manufacturers and bodybuilding magazines tout its ability to allow athletes to train harder and recover more quickly. However, its use as a performance-enhancing drug is illegal in the United States.

Scientific studies that refute these claims show that supplemental androstenedione doesn't increase testosterone and that your muscles don't get stronger with andro use. In fact, almost all of the andro is rapidly converted to estrogen, the primary hormone in females.

Risks
Side effects of andro in men include:

  • Acne
  • Diminished sperm production
  • Shrinking of the testicles
  • Enlargement of the breasts

In women, side effects include:

  • Acne
  • Masculinization, such as deepening of the voice and male-pattern baldness

In both men and women, andro can decrease HDL cholesterol (the "good" cholesterol), which puts you at greater risk of heart attack and stroke.

What is it?
Human growth hormone, also known as gonadotropin, is a hormone that has an anabolic effect. Athletes take it to improve muscle mass and performance. However, it hasn't been shown conclusively to improve either strength or endurance. It is available only by prescription and is administered by injection.

Risks
Adverse effects related to human growth hormone range in severity and may include:

  • Joint pain
  • Muscle weakness
  • Fluid retention
  • Carpal tunnel syndrome
  • Impaired glucose regulation
  • Cardiomyopathy
  • High cholesterol (hyperlipidemia)
  • Diabetes
  • High blood pressure (hypertension)

What is it?
Erythropoietin is a type of hormone used to treat anemia in people with severe kidney disease. It increases production of red blood cells and hemoglobin, resulting in improved movement of oxygen to the muscles. Epoetin, a synthetic form of erythropoietin, is commonly used by endurance athletes.

Risks
Erythropoietin use among competitive cyclists was common in the 1990s and allegedly contributed to at least 18 deaths. Inappropriate use of erythropoietin may increase the risk of thrombotic events, such as stroke, heart attack and pulmonary edema.

What are they?
Diuretics are drugs that change your body's natural balance of fluids and salts (electrolytes) and can lead to dehydration. This loss of water can decrease an athlete's weight, helping him or her to compete in a lighter weight class, which many athletes prefer. Diuretics may also help athletes pass drug tests by diluting their urine and are sometimes referred to as a "masking" agent.

Risks
Diuretics taken at any dose, even medically recommended doses, predispose athletes to adverse effects such as:

  • Dehydration
  • Muscle cramps
  • Exhaustion
  • Dizziness
  • Fainting
  • Potassium deficiency
  • Heart arrhythmias
  • Drop in blood pressure
  • Loss of coordination and balance
  • Heatstroke
  • Death

What is it?
Many athletes take nutritional supplements instead of or in addition to performance-enhancing drugs. Supplements are available over-the-counter as powders or pills.

The most popular supplement among athletes is probably creatine monohydrate. Creatine is a naturally occurring compound produced by your body that helps your muscles release energy.

Scientific research indicates that creatine may have some athletic benefit by producing small gains in short-term bursts of power. Creatine appears to help muscles make more adenosine triphosphate (ATP), which stores and transports energy in cells, and is used for quick bursts of activity, such as weightlifting or sprinting. There's no evidence, however, that creatine enhances performance in aerobic or endurance sports.

Your liver produces about 0.07 ounces (2 grams) of creatine each day. You also get creatine from the meat in your diet. Creatine is stored in your muscles, and levels are relatively easily maintained. Because your kidneys remove excess creatine, the value of supplements to someone who already has adequate muscle creatine content is questionable.

Risks
Supplements are considered food and not drugs by the FDA. This means supplement manufacturers are not required to conform to the same standards as drug manufacturers do. In some cases, supplements have been found to be contaminated with other substances, which may inadvertently lead to a positive test for performance-enhancing drugs.

Possible side effects of creatine that can decrease athletic performance include:

  • Stomach cramps
  • Muscle cramps
  • Nausea
  • Diarrhea
  • Weight gain

Weight gain is sought after by athletes who want to increase their size. But with prolonged creatine use, weight gain is more likely the result of water retention than an increase in muscle mass. Water is drawn into your muscle tissue, away from other parts of your body. This puts you at risk of dehydration.

High-dose creatine use may potentially damage your:

  • Kidneys
  • Liver

It appears safe for adults to use creatine at the doses recommended by manufacturers. But there are no studies investigating the long-term benefits and risks of creatine supplementation.

What are they?
Some athletes use stimulants to stimulate the central nervous system and increase heart rate and blood pressure.

Stimulants can:

  • Improve endurance
  • Reduce fatigue
  • Suppress appetite
  • Increase alertness and aggressiveness

Common stimulants include caffeine and amphetamines. Cold remedies often contain the stimulants ephedrine or pseudoephedrine hydrochloride. Energy drinks, which are popular among many athletes, often contain high doses of caffeine and other stimulants. The street drugs cocaine and methamphetamine also are stimulants.

Risks
Although stimulants can boost physical performance and promote aggressiveness on the field, they have side effects that can impair athletic performance.

  • Nervousness and irritability, which make it hard to concentrate on the game.
  • Insomnia, which can prevent an athlete from getting needed sleep.
  • Dehydration.
  • Heatstroke.
  • Addiction or tolerance, meaning that athletes need greater amounts to achieve the desired effect, so they'll take doses that are much higher than the intended medical dose.

Other side effects include:

  • Heart palpitations
  • Heart rhythm abnormalities
  • Weight loss
  • Tremors
  • Mild high blood pressure (hypertension)
  • Hallucinations
  • Convulsions
  • Stroke
  • Heart attack and other circulatory problems

Do performance-enhancing drugs boost performance? Some athletes may appear to achieve physical gains from such drugs, but at what cost? The long-term effects of performance-enhancing drugs haven't been rigorously studied. And short-term benefits are tempered by many risks. Not to mention that doping is prohibited by most sports organizations. No matter how you look at it, using performance-enhancing drugs is risky business.

Dec. 12, 2012