Gwen Knapp

About the author: Gwen Knapp is a sports journalist for the San Francisco Chronicle.

Athletes are using dietary supplements purchased from health-food stores to boost their athletic performance. Many of these products are advertised as having the same effects on muscle development as prescription-only performance-enhancing drugs, and studies have shown that some supplements convert to illicit steroids once ingested. Supplement use has been linked to the deaths of several athletes, who exceeded the recommended dosages or mixed their intake of supplements with other medications. Because the supplement industry is virtually unregulated due to a 1994 law passed by Congress, consumers should use caution when purchasing performanceenhancing dietary supplements.

Open up the liquor cabinets. Turn over the car keys. And—what the heck"—hand out cigarettes for Halloween.

No age limits on supplement sales

If an...