New York Yankees pitcher Roger Clemens, who was recently outed by a New York tabloid for using Viagra to increase his performance on the field, is among many professional athletes who make unorthodox use of pharmaceutical drugs.
Experts believe athletes and performers use a strange and alarming array of methods to keep themselves competitive in two of the most competitive careers in America, often at their own peril.
Although it may seem counterintuitive, Viagra -- which Major League Baseball does not prohibit -- works by relaxing muscles and increasing blood flow through the body.
Dr. Robert Dimeff, president of the American Medical Society for Sports Medicine, says that doctors first became aware of athletes' "off-label" use of drugs like Viagra a few years back, when cyclists, who "love to experiment with weird performance-enhancing stuff anyway," reported that it helped improve performance.
Dimeff says he presumes that their improvement at high altitudes is due to improved oxygenation of mild or "subclinical" pulmonary edema and inefficiency.
Dimeff also says that while large-scale, double-blind studies are necessary to confirm these reports, when they do not exist, doctors must rely on small studies and anecdotal evidence. And, of course, their pharmacological training.
A study presented in 2006 at an American College of Sports Medicine conference indicated that the potent ingredients in Viagra and Cialis, which treat erectile dysfunction, did seem to improve lung function by increasing oxygenation of the blood to the lungs.
Sylvester Stallone, on the other hand, says he prefers to use human growth hormone to keep his 61-year-old self looking tight.
The muscly actor told "Today's" Matt Lauer five months ago that he does indeed take the substance and has no qualms about saying so.
Stallone, who pleaded guilty to possession after Australian airport officials last year found 48 vials of human growth hormone in his luggage, emphasized that his physique is buff because of years and years of training.
The hormones serve only as enhancement to an already strong body, he said.
Human growth hormone, he said "really takes off the wear and tear that your body takes."
Some bodybuilders and other athletes also sing its praises, claiming that it improves vision and makes for faster muscle recovery after workouts.
Dimeff says that if there were a shred of evidence that the hormone could improve eyesight, he'd be taking it himself. There is not.
But it is generally accepted in the medical community that the growth hormone can increase metabolism and protein synthesis, which means that with exercise, one can potentially grow leaner. He qualifies his comments, however, by emphasizing the significance of the placebo effect.
Because the word "placebo" has come to mean, at least in layman's terms, that whatever forces at work are not "real," Dimeff dislikes using the term.
But in most every study the placebo effect is so significant that it accounts for a 30 percent improvement in any given condition. "Just thinking you are taking something can make you feel better, but it is very real, very profound," he says.
That said, Dimeff says human growth hormone does accelerate the body's recovery from strenuous exercise as well as increase protein growth.