What You Don't Know Might Kill You

• A 2003 study claimed that an extract of brown seaweed binds to and blocks myostatin, a protein that tells muscles when to stop growing. Companies such as Biotest and Champion Nutrition rushed brown-seaweed-extract supplements to market. After two later studies debunked the seaweed-as-muscle-builder theory, Tim Ziegenfuss, one of the authors of the pro-seaweed study and now a Biotest scientist, conceded in an online interview with the website Testosterone Muscle that "the science was just so promising that we just didn't follow the process like we usually do in terms of stringent testing.... [The supplement companies] were in too big a hurry to get it to market."

• Some oral spray or liquid products claim to contain human growth hormone. Whether they do or do not is unimportant, since HGH is a very large molecule that is not effective unless taken by injection and can be legally obtained only with a prescription.

• Ginseng has been used in China for thousands of years, as many supplement makers will inform a consumer looking for a boost in the gym or on the field. But a few well-designed scientific studies, according to UC Berkeley's Wellness Guide to Dietary Supplements website, have found no proof that ginseng enhances energy levels or athletic performance.

• Almost every sports-supplement store sells products that contain the steroid prohormone DHEA, which is legal but banned by the NCAA, the NFL, the NBA and WADA. DHEA is marketed for everything from muscle growth and fat loss to antiaging. Levels of DHEA in the body do decline with age, but in scientific studies on thousands of senior citizens, supplemental DHEA failed to improve muscle mass or brain function. Studies have, however, documented side effects, including facial hair growth in women and breast enlargement and elevated blood pressure in men, in addition to a number of dangerous interactions for those also taking prescription drugs.

Even some of the biggest names in supplements can find themselves embroiled in debates about the scientific basis of their product claims. At issue in an ongoing class action lawsuit in California is whether Bioengineered Supplements and Nutrition (BSN), the official supplement provider of the Ultimate Fighting Championship, falsely marketed products as containing its breakthrough ingredient: creatine ethyl ester malate, or CEM3. CEM3 was touted as one of the components of BSN's muscle-building N.O.-XPLODE, a product that was so successful when it was launched in 2004 that BSN doubled its staff to about 60 employees within a year. (In 2007 the company was named the 27th-fastest-growing private company in America by Inc. magazine, with $80.8 million in revenue and a three-year growth rate of 3,027%.) "You probably can't go into any store in the world where [N.O.-XPLODE] is not a top seller," says James Tracy, BSN's marketing director.

But whether CEM3 even exists is at the crux of the lawsuit. In expert depositions Jonathan Vennerstrom, professor of pharmaceutical sciences at the University of Nebraska Medical Center, testified that the claimed structure of CEM3 is chemically impossible to make, and Richard Chamberlin, a chemistry professor at UC Irvine, testified that BSN's patented process for synthesizing CEM3 "almost certainly would produce none." BSN told SI that the lawsuit "does not challenge the effectiveness or quality of the products," and that "BSN no longer sells those formulations."

Some supplement makers, prohibited by cost and their lack of expertise from creating novel ingredients, fall back on what they know works and sells: anabolic steroids and prohormones that have not yet been added to the DEA's list of controlled substances.

The policing of these designer compounds has become a cat-and-mouse game between retailers and the feds. Andro and its prohormone cousins were added to the federal controlled substances list in 2004. Supplement makers responded by engineering new prohormones; whether one is technically legal depends in part on how chemically and pharmacologically similar it is to a controlled substance. "Designer drugs are hard to keep up with," says Rusty Payne, a DEA spokesman. "We're adapting and evolving, and the bad guys are doing the same thing to evade us."

The government is already working to ban more prohormones, and though the FDA does not have premarket approval power, it does test products when concerns arise. (A month after the six NFL players were suspended because of the banned diuretic in StarCaps, the FDA announced that 69 weight-loss supplements had been found to contain unlisted drugs. The FDA warned consumers but doesn't have the authority to issue a recall without the manufacturers' cooperation.) The approach to take with prohormones, says a person who works directly with retailers at a large supplement-manufacturing company, is to "make your money in the next few months and get out of it."

The market for over-the-counter or over-the-Internet products containing steroids and prohormones, in the words of the manufacturing-company employee, is "the 15-year-old boy to the 25-year-old [man] who just is, like, I don't want to take steroids, and I heard this is going to make me have great [muscle] gains."