The few good scientific studies available on these “dietary” supplements suggest that they either are ineffective or, at best, produce only slight changes in performance. More disturbing, they can contain powerful and potentially harmful substances, such as:
Androstenedione, which can upset the body’s hormonal balance when it metabolizes into testosterone and estrogen okinawa flat belly reviews , and may cause premature puberty and stunted growth in adolescents.
Creatinine, a substance produced by the body that can help generate brief surges of muscle energy during certain types of athletic performance. Many others who use creatine monohydrate, a supplement used as a derivative, can gain up to 15 pounds and gain muscle mass. However, it is mostly water retention. After you stop taking the supplement, you will lose the weight and feel less strong. Again, nothing lasts a lifetime. Another negative side is that you can’t constantly use creatine since this would cause your body to permanently stop producing creatinine (body produces it naturally). You can be on it for just a couple of month and then take it again a year later.
Ephedra, a herbal stimulant that acts like an amphetamine (“speed”) and that some investigators hold responsible for dozens of deaths and permanent injuries.
“All you have to do to get these products is walk into a food-supplement store,” says Gary Wadler, M.D., a New York sports-medicine specialist and adviser to the White House Office of National Drug Control Policy. That’s because a federal law, the 1994 Dietary Supplement Health and Education Act, allows supplements to be sold to consumers of any age without rigorous safety testing and without meaningful oversight of product quality.
Little is known about the long-term safety of these products in adults, and even less about their effect on youngsters. However, if the supplement industry has its way, at least ever-increasing numbers of week-end athletes will consume some of these products.
“Sports nutrition isn’t just for hard-core athletes any more,” Anthony Almada, president of a California supplement company, told an industry journal. “It’s for anyone seeking energy improvement,” he said, or “a woman who wants to tone her body and lose a few pounds, or a person who rides a bike and wants to perform like an athlete.”
Nutrition Business Journal, a trade publication that tracks the industry, estimates that 4 percent of American adults have taken a sports supplement at least once, including 1.2 million who use the products regularly.
Adolescents are using sports supplements at least as enthusiastically as adults are, according to a national survey conducted in 1999 for Blue Cross and Blue Shield Association. The survey found that 6 percent of youths ages 15 to 16 and 8 percent of 17- and 18-year-olds had taken a sports supplement; the vast majority of users were male. About one in four respondents said they knew someone who took the products.