Frank LoVecchio, DO, is a medical toxicologist at the Banner Poison and Drug Information Center.
Question: Are over-the-counter (OTC) weight-loss pills safe? Are they proven effective?
Answer: Most over-the-counter weight-loss pills haven't been proved effective, and some may be downright dangerous.
Dietary supplements and weight-loss aids aren't subject to the same rigorous standards as are prescription drugs. Thus, they can be sold without proof of effectiveness or safety. Once a product is on the market, however, the Food and Drug Administration (FDA) monitors its safety and can take action to ban or recall dangerous products once they believe harm has been done.
Many weight-loss pills contain multiple ingredients, such as herbs, botanicals, vitamins, minerals and even caffeine or laxatives. If you take prescription drugs – or herbal or dietary supplements – adding weight-loss pills to the mix can be tricky.
- Alli is the OTC version of prescription drug orlistat (Xenical). It decreases absorption of dietary fat and may be effective – although weight-loss amounts are typically less for OTC versus prescription. The FDA is investigating reports of liver injury associated with orlistat use.
- Chromium, typically chromium III, is thought to increase calories burned, decrease appetite and builds muscle, but there is insufficient reliable evidence to state it has any benefit. Chromium (IV) has been associated with cancer.
- Country mallow (heartleaf) and Ephedra have been shown to decrease appetite and increase calories burned. However they are considered unsafe and have been banned by the FDA.
- Green tea extract is thought to increase calorie and fat metabolism and decrease appetite. It is not well studied, but appears safe at this point.
- Guar gum is thought to block absorption of dietary fat and increase the feeling of fullness. Although effectiveness has not been studied, adverse events have not been reported.
- Hoodia Gordonii is the African plant extract that presumably suppresses appetite. It is currently selling well, yet there is only the slimmest of evidence that this diet supplement works. Even if it does, many of the pills on sale now may contain little or none of the active ingredient. So far, there have been no data on human testing published in reputable medical journals on Hoodia. Even unpublished data are inconclusive or based on very short time periods. Side effects from Hoodia are not reported, but further testing is needed to provide accurate effects.
The bottomline is even if you take a weight-loss pill, you still have to eat fewer calories than your body uses in order to lose weight.