What do home-run king Mark McGwire, French tennis champ Mary Pierce, international soccer star Zinedine Zidane, British sprinter Linford Christie, and NFL tight end Shannon Sharpe all have in common? All have spoken openly to the media about their use of creatine supplements in athletic training.

According to Nutrition Business Journal, a trade publication of the dietary supplement industry, sales of performance-enhancing nutritional supplements skyrocketed when McGwire spoke publicly of his creatine and androstenedione (andro) use during the media blitz surrounding his 70 single-season home-run hitting streak in the 1998 major league baseball season. The professional athlete as role model is a time-honored tradition in the U.S., and corporations such as McDonald's and General Mills scrambled to sign up McGwire to endorse Wheaties and Big Macs following his recordbreaking season.

The full impact that the well-publicized use of supplements by sports icons has had on...