The Federal Trade Commission regulates the marketing of diet pills and supplements. While a 2006 study from the Center for Survey Research and Analysis at the University of Connecticut found that 54 percent of respondents believed that dietary supplements, including fat burners, were approved by the Food and Drug Administration (FDA), the opposite is true.

On the Other: FDA Warnings

Though the FDA doesn't regulate fat burners, the Dietary Supplement Health and Education Act of 1994 provides some protection. If the FDA finds that a fat burner isn't safe, it can be banned from being sold as such. In March of 2009, the FDA added several fat burners to its warning list, stating that the manufacturers were adding "undeclared, active pharmaceutical ingredients."

Bottom Line

The Mayo Clinic says that while some fat burners, like Chitosan and Chromium, may be considered fairly safe, they're unlikely to spur weight loss. Plus, long-term effects haven't been studied adequately. The supplements that may cause weight loss may also engender side effects such as diarrhea, high blood pressure, heart failure and even death. Fat burners, in general, are either unsafe or ineffective in most cases.

Source:

FDA: Overview of Dietary Supplements

Consumer Research: Are Diet Pills Safe?

FDA: News Release on Tainted Weight Loss Products

Resource:

FTC: Dietary Supplements: An Advertising Guide for the Industry

Mayo Clinic: Over-the-Counter Weight-Loss Pills: Do They Work?