You may see ads for supplements that claim they will help you lose weight. But many of these claims are not true. Some of these supplements can even have serious side effects.
Note for women: Pregnant or nursing women should never take diet medicines of any kind. This includes prescription, herbal, and other over-the-counter remedies. Over-the-counter refers to medicines, herbs, or supplements you can buy without a prescription.
Weight-loss product options
There are many over-the-counter diet products, including many herbal remedies. Most of these products do not work. Some can even be dangerous. Before using an over-the-counter or herbal diet remedy, talk with your doctor.
Nearly all over-the-counter supplements with claims of weight-loss properties contain some combination of these ingredients:
EPA-rich fish oil
There is no proof that these products help with weight loss.
Safety of over-the-counter products
Some ingredients in over-the-counter diet products may not be safe. The Food and Drug Administration (FDA) warns people not to use some of them. Do not use products that contain these ingredients:
Ephedrine is the main active ingredient of herbal ephedra, also known as ma huang. The FDA does not allow the sale of medicines that contain ephedrine or ephedra. Ephedra can cause serious side effects, including strokes and heart attacks.
Brazilian diet pills are also known as Emagrece Sim and Herbathin dietary supplements. The FDA has warned consumers not to buy these products. They contain stimulant drugs and drugs used to treat depression. These can cause severe mood swings.
Conjugated linoleic acid (CLA) is found in many diet products (such as Biosculpt Liquid, Body Success, and GNC Optibolic Body Answers Dietary Formula). Possible side effects include risk of diabetes and gallstones.
Tiratricol is also known as triiodothyroacetic acid or TRIAC. These products contain a thyroid hormone, and they may increase the risk for thyroid disorders, heart attacks, and strokes.
Fiber supplements that contain guar gum have caused blockages in the intestines and esophagus, the tube that carries food from your mouth to your stomach and intestines.
Chitosan is a dietary fiber from shellfish. Some products that contain chitosan are Natrol, Chroma Slim, and Enforma. People who are allergic to shellfish should not take these supplements.
Nicolai JP, Lupiani JH, Wolf AJ. An integrative approach to obesity. In: Rakel D, ed. Integrative Medicine. Philadelphia, PA: Saunders Elsevier; 2012:chap 38.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.