And although there have been reports of joint pain and increased risk of diabetes associated with its use, Dimeff says that unlike steroids, which linger in body, the growth hormone stays for no longer than nine hours. Therefore, he says, the risk of side effects is minimal.
But the hormone is very expensive. Bodybuilders who want an extra boost may find that Preparation H, the hemorrhoid-fighter with the distinctive metallic odor, fits better into their budgets.
For competitors who want to target problem areas before a big contest, the anti-inflammatory shrinks tissue temporarily. Trouble can come when old faithful is used regularly for extended periods of time, doctors say.
Darrell S. Rigel, clinical professor of dermatology at New York University Medical Center, warns that because it works by constricting blood vessels, Preparation H may raise one's blood pressure.
Baking soda is another athlete's underground secret. Runners have ingested baking soda before races for decades -- it's called "soda-doping."
Enthusiasts compare it to carbohydrate loading before a race.
But Ronald W. Deitrick, fellow of the American College of Sports Medicine, recently told members at their annual conference that although his studies show that giving runners baking soda in capsule form did seem to improve the performance of middle distance runners -- and with few side effects (diarrhea being the worst case scenario) -- he believes its use should be banned.
"I think it violates the spirit of fair play," he told the group.
Gymnasts, wrestlers and dancers have to maintain a low weight in order to stay competitive, but according to experts, jockeys have it particularly hard.
In other sports, being a little above ideal weight simply puts one at a disadvantage, says Ron Johnson, co-author of Helping Athletes with Eating Disorders. But if a jockey doesn't "make weight," he won't be allowed to ride. Making weight means making rent.
The average jockey is a little taller than five feet and weighs 110 to 112 pounds. In order to maintain that weight, he says, jockeys often restrict their calorie intake to 500-800 a day, and just before the weekend when they race, sweating in rubber suits, purging with laxatives and vomiting ("flipping" in jockey parlance) is more than common.
So common, in fact, that the bathrooms for jockeys at many tracks feature oversized, square toilets and saunas -- aka "the hotbox" -- to facilitate quick weight loss.
Not surprisingly, this all takes a toll on a jockey's body.
But Johnson says that in large part kidney failure, heart problems and tooth and gum decay are all seen as occupational hazards by the athletes, who exist in a subculture where purging and starvation is the norm.
Athletes who practice severe forms of experimental enhancements are certainly taking a risk, even if the risks are -- as of yet -- unknown or unproved. For example, athletes who practice severe calorie restriction may not believe they have a psychological problem, but experts believe that starving and purging is likely to create one.