Natural Metabolism Pills

As the rate of overweight and obese Americans surpasses two-thirds of the adult population, many unscrupulous health supplement manufacturers are attempting to cash in on the desire for a quick, easy weight-loss supplement by advertising false claims of rapid weight loss without exercise or dieting. Many of the "natural metabolism boosting pills" actually contain dangerous chemicals that are either controlled substances or untested. If any claim on a weight-loss supplement sounds too good to be true, it probably is. Like any health supplement, consult your doctor before taking any natural metabolism pill.

Metabolism Supplements

Many different factors contribute to your metabolic rate, including your genes, muscle mass and activity level. Permanent changes in your metabolic rate only occur gradually over time; scientists have not yet invented a magic supplement that will dramatically increase your metabolism and result in rapid weight loss. Only sustained changes in behavior and eating patterns can actually have a long-term effect on your metabolism, explains the University of California, Los Angeles.

Stimulants

Many weight-loss supplements contain stimulants, such as caffeine or ephedra, that can cause a temporary increase in metabolic rate by causing your body to generate more heat, but this effect does not last long enough to contribute significantly to weight loss, explains the University of California, Los Angeles. Additionally, these stimulants often cause side effects such as increased blood pressure, elevated heart rate, nausea, vomiting, slurred speech, blurred vision, confusion, loss of physical coordination and dizziness, warns the California Department of Health. Cases that have resulted in death have even been linked to natural metabolism supplements, reports the U.S. Food and Drug Administration.

Other Chemicals

Many supposedly "natural" metabolic supplements actually contain prescription drugs such as sibutramine. Medications containing sibutramine were banned by the FDA in 2010 due to dangerous side effects, including stroke and heart attack. Weight-loss pills may contain many other powerful prescription medications that are not on the label, such as blood pressure and seizure medications, warns the FDA. Because health supplements are not regulated by the FDA, the safety and effectiveness of these products is not tested before they are sold in stores.

False Advertising

Many government agencies, including the FDA and the Federal Trade Commission, are trying to cut down on dangerous, fraudulent weight-loss supplements. Since 2004, the FTC has investigated many manufacturers of natural metabolism boosters for making false claims about the safety and effectiveness of weight-loss pills. According to the FTC, many of the advertising claims that promise to block absorption of fat or allow you to lose weight fast without diet or exercise are blatantly false.