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Over-the-counter weight-loss pills: Do they work?

The temptation of using over-the-counter weight-loss pills to lose weight fast is often irresistible. But are these products safe and effective?

By Mayo Clinic staff

The appeal of losing weight quickly is hard to pass up. But do over-the-counter weight-loss pills and products lighten anything but your wallet? And are they a safe option for weight loss? Here's a look at some non-prescription weight-loss pills and what they will and won't do for you.

Popular weight-loss pills

A number of weight-loss pills are available at your local drugstore, supermarket or health food store. Even more options are available online. Most haven't been proved safe and effective, and some are downright dangerous.

Herbal or dietary supplementThe claimsWhat you need to know
Bitter orange Increases the number of calories burned
  • Touted as an "ephedra substitute" but may cause health problems similar to those of ephedra
  • Long-term effects unknown
Chitosan Blocks the absorption of dietary fat
  • Relatively safe, but unlikely to cause weight loss
  • Can cause constipation, bloating and other gastrointestinal complaints
  • Long-term effects unknown
Chromium Reduces body fat and builds muscle
  • Relatively safe, but unlikely to cause weight loss
  • Long-term effects unknown
Conjugated linoleic acid (CLA) Reduces body fat, decreases appetite and builds muscle
  • Might decrease body fat and increase muscle, but isn't likely to reduce total body weight
  • Can cause diarrhea, indigestion and other gastrointestinal problems
Country mallow (heartleaf) Decreases appetite and increases the number of calories burned
  • Contains ephedra, which is dangerous
  • Likely unsafe and should be avoided
Ephedra Decreases appetite
  • Can cause high blood pressure, heart rate irregularities, sleeplessness, seizures, heart attacks, strokes and even death
  • Banned from the marketplace because of safety concerns, but may still be legally sold as a tea
  • Despite the ban, many ephedra products are still sold on the Internet
Green tea extract Increases calorie and fat metabolism and decreases appetite
  • Limited evidence to support the claim
  • Can cause vomiting, bloating, indigestion and diarrhea
  • May contain a large amount of caffeine
Guar gum Blocks the absorption of dietary fat and increases the feeling of fullness, which leads to decreased calorie intake
  • Relatively safe, but unlikely to cause weight loss
  • Can cause diarrhea, flatulence and other gastrointestinal problems
  • May cause intestinal obstruction if not taken with enough water
Hoodia Decreases appetite
  • No conclusive evidence to support the weight-loss claim

In addition to these herbal and dietary supplements, the Food and Drug Administration (FDA) has approved Alli — a reduced-strength over-the-counter (nonprescription) version of orlistat, a prescription weight-loss medication for adults age 18 and older. Alli promotes weight loss by decreasing absorption of fat by the intestines. The capsules are taken with meals, up to three times a day.

Alli sounds like a dieter's dream, but there are no shortcuts to permanent weight loss. Alli is intended to be used only with a reduced-calorie, low-fat diet and regular exercise. Side effects, such as diarrhea and gas with oily spotting, can be significant if you don't reduce the amount of fat in your diet.

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Feb. 15, 2008

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