Supplemental Information

But while results are impressive, it's important to note that PrePair's studies were small, and not published in any medical journal, which means they were not subject to review by experts who could verify either the results, or the conditions under which the testing was carried out.

Moreover, even if PrePair can elevate heat shock proteins after fitness activities, as it claims, some experts question whether that elevation is really key to the repair process - or just something that occurs simultaneously.

"The big question now is will the elevation of heat shock proteins following stressors - using this supplement or any other means - really reduce muscle damage or increase the recovery process," says Malachy McHugh, PhD, director of research, Nicholas Institute of Sports Medicine and Athletic Trauma in New York City.

While McHugh remains intrigued with the link between heat shock proteins and exercise, he cautions that right now there is no science to show that they make a difference in recovery, or if they do, if speeding up production with a supplement has any real value.

"Ultimately, you need some measure of damage or disruption of the cells to see if those who take the supplement fare better than those who don't," McHugh tells WebMD.

Nutrition expert and author Shawn Talbott, PhD, agrees. "The question that needs to be answered is whether or not impacting heat shock proteins is going to impact the rate of injury or fatigue, or make fitness workouts safer - and right now we have no well controlled peer reviewed studies to tell us that," says Talbott, a professor at The University of Utah and the author of "The Cortisol Connection."

And, in fact, there is already one animal study that shows that, on it's own, elevated HSP may not make much of a difference at all. In preliminary research presented at the ACSM conference in May, doctors from Georgia State University in Atlanta used heat to increase production of HSP in mice. While they clearly documented elevations in HSP, it did not appear to protect the mice against exercise induced injury - or speed their recovery afterwards.

Although the company who makes PrePair provided WebMD with toxicity studies on mice showing the supplement was proven safe, and says thousands of products sold have yielded no reports of adverse effects, Gotlin believes this is not enough proof to offer a blanket guarantee of safety to all fitness buffs who use it.

"I would need large-scale human trials before I would take this supplement, or recommend it," says Gotlin.

Talbott is more certain of the safety aspect and says he would recommend the product. However, he tells WebMD, "I'm just not sure if raising heat shock proteins has been proven to make a significant difference in our fitness activities."

Published June 30, 2003

Sources: Robert Gotlin, MD, director of Orthopedics and Sports Rehabilitation at Beth Israel Medical Center in New York City; Marilyn Booker, RN, clinical director, Perfect Equation; Malachy McHugh, PhD, director of research, Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York City; Shawn Talbott, PhD, professor, University of Utah, fellow, American College of Sports Medicine; "Attenuation of Muscle Damage by Muscle Hyperthermia One Day Prior to Eccentric Exercise",annual meeting, American College of Sports Medicine, San Francisco, May, 2003; Medicine and Science in Sports and Exercise, 2000, 32:592-600; White Paper: Tex-OE?, A Natural Cactus Extract With The Ability to Accelerate The Synthesis of Protective Heat Shock Proteins (HSPs); "Effects of Prophylactic Heating On Eccentric Contraction-Induced Injury in Mouse Skeletal Muscle", annual meeting, American College of Sports Medicine, May, 2003, San Francisco.