If you've ever questioned the credibility of some the claims in those weight-control commercials, then you're not alone. The FTC also has its doubts and has made it publicly known. The consumer watchdog agency recently settled with the marketers of Xenadrine EFX, CortiSlim, TrimSpa, and One-A-Day WeightSmart to surrender cash and other assets worth at least $25 million for false and/or misleading claims the marketers made while promoting its products.

The FTC's complaint alleges that the defendants made false or unsubstantiated claims for Marketers for Xenadrine EFX, which contains green tea extract and caffeine, claimed it was clinically proven to cause rapid and substantial weight loss. In actuality, says the FTC, the subjects taking the supplement lost an average of only 1.5 to 2.5 pounds over the 10-week study. The FTC also reprimanded the marketers for not disclosing other vital information to the public, like the $1,000 to $20,000 it paid the endorsers for their testimonials.

Similarly, the FTC says the marketers of CortiSlim and CortiStress, made false claims that their products can cause weight loss and reduce the risk of, or prevent, serious health conditions such as osteoporosis, obesity, diabetes, Alzheimer's disease, cancer, and cardiovascular disease.

The FTC also charges that marketers of TrimSpa couldn't properly substantiate their claims. One of claims was in regards hoodia gordonii, a South African herb that is marketed as an appetite suppressant. Celebrity Anna Nicole Smith claimed to have lost 69 pounds in eight months by using TrimSpa.

Likewise, marketers of One-A-Day WeightSmart heralded one of its main ingredients, green tea extract, as its magic formula to speed up metabolism and control their weight.

Unfortunately, none of the marketers could come up with strong scientific evidence to back their claims. "Paying for fad science is a good way to lose cash, not pounds," said Deborah Platt Majoras, FTC chairman. In addition to the money each marketer must pay, each company is required to limit their future advertising claims.