Yes, they do. But published evidence that they reduce weight is in short supply.

Here is a study of a thermogenic formulation and recent legal actions against weight lose products by the Federal Trade Commission (FTC).

  • 31 people drank 3 servings of a beverage containing green tea catechins, caffeine, and calcium for 3 days.
  • They also drank a placebo beverage for comparison.
  • 24-hour energy expenditure was measured.

And the results

  • The green tea catechins, caffeine, and calcium drink increased energy expenditure 4.6%.
  • The contribution of individual ingredients could not be distinguished.
  • Men burned more fat than women, although both had a significant response.

The bottom line

  • “Such a beverage may provide benefits for weight control,” the researchers concluded.
  • Future studies will be needed to prove this effect, however.

And the FTC is watching. Four cases involving the marketing of diet products using unsubstantiated weight loss claims were settled in January 2007.

Xenadrine EFX

  • $12.8 million for false and unsubstantiated weight-loss claims
  • In one study, it actually caused less weight loss than a placebo.
  • Endorsers were paid up to $20,000 for testimonials.
  • Xenadrine contains green tea extract, caffeine, and bitter orange (Citrus aurantium).

CortiSlim and CortiStress

  • $12 million settlement
  • CortiSlim claimed the product would cause “rapid, substantial, and permanent weight loss in all users.”
  • CortiStress claimed the product reduced the risk of Alzheimer’s disease, cancer, and other illnesses.

Can you say “hutzpah”?


  • $1.5 million
  • Unsupported claims that it causes rapid and substantial weight loss.
  • And that one of its ingredients, Hoodia gordonii, suppresses appetite.

Here is an earlier post on Hoodia.

One-a-Day WeightSmart multivitamins

  • $3.2 million
  • Claimed to prevent weight gain associated with metabolic decline in people over 30
  • One ad suggested that the “lifting, twisting, and bending” needed to open the bottle was the only exercise required to lose weight.

More information on these legal actions and a review of energy and weight-loss ingredients are available at Nutritional Outlook.

The FTC has a brochure that lists weight loss claims that are too good to be true.

3/1/07 09:38

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.