"What You Don't Know Might Kill You" by Sports Illustrated.

"Would-be experts and untested products feed a $20 billion obsession with better performance across all levels of sports.

Gonzalez has no background in chemistry or nutritional science. His previous job was restoring cars; before that he was in the Marines. What he knows about sports supplements—those pills, powders and drinks marketed to athletes and would-be athletes—he learned from using them (initially as a chubby adolescent hoping to add muscle) and from reading articles in magazines and online. Except for his own experiences, there is nothing to suggest that he is qualified to offer advice on supplementation, let alone to design and manufacture his own line of products.

All it takes to become a sports supplement dealer is a little money and a phone call, like the one Gonzalez placed last year to a supplement manufacturer in Texas. Gonzalez ordered bottles of a muscle-building product that he named Monsterdrol, which were then made, packaged and marked with Gonzalez's label, Supplements911. When showing a visitor around his store in February, Gonzalez pointed to a bottle of Monsterdrol and described it as "your typical prohormone product." A steroid prohormone is a substance that the body converts to an anabolic steroid; andro is an example. But Dr. Don Catlin—CEO of Anti-Doping Research, a Los Angeles--based nonprofit that hunts down new performance enhancers, and the former director of the UCLA Olympic Analytical Laboratory—says that Monsterdrol is in fact methasteron, an anabolic steroid that, while not on the controlled substance list of the Drug Enforcement Administration (DEA), is "Number 1 on my danger list."

A very interesting read if you want to know more about the 'legal' supplements industry.