What are OTC diet pills?
Only one over-the-counter diet pill is approved for weight loss: a reduced-dose formulation of orlistat known as Alli. It works by preventing absorption of about a third of ingested fat. While side effects from Alli are slightly lower than with its prescription cousin (because of the lower dose): they remain unpleasant: oily stools and discharge and potential bowel accidents if too much fat is eaten at one sitting. Alli's manufacturer recommends keeping total fat consumption to about 30% of calories a day and spreading it out over three meals. The net weight loss effect with Alli: about 50% greater than diet and exercise alone.
What do I need to know about OTC diet supplements?
Many other over the counter diet supplements are promoted as helping with weight loss, but few have actually been proven to work. Worse, some of the ingredients used in OTC diet supplements may be dangerous. The Food and Drug Administration classifies herbal products as dietary supplements. This means that they are unregulated and can be marketed without the years of testing and regulatory review required for prescription (and nonprescription) drugs. Remember that supplements can have side effects, and you should check with your doctor first before taking any type of supplement, including OTC diet pills.
Here are some common ingredients seen in OTC diet supplements:
Green tea extract: cases of liver problems in people using concentrated green tea extracts have been reported.
Hydroxycitric acid: Derived from the fruit of a tree native to Southeast Asia. It generally appears to be safe, although one maker recalled its products after they were associated with liver damage. Other health problems reported included seizures, cardiovascular disorders, and serious muscle damage. These products contained many other ingredients, and it is unclear which ingredients or doses were associated with the liver problems.
Chromium: A mineral that people can get through diet, particularly meats, whole-grains, and some vegetables and fruits. It has been linked to side effects such as headaches and dizziness as well as more serious health problems at high doses.
Conjugated linoleic acid (CLA): Found naturally in meat and dairy products, it may cause stomach upset.
Hoodia: Derived from an African plant native to the Kalahari Desert. Hoodia products typically contain other additional ingredients. Its safety is not yet known.
Chitosan: Made from the starch found in shellfish.
Pyruvate: Produced by the body as a result of the breakdown of carbohydrate and protein from food and found naturally in foods such as cheese, wine, and red apples.
St. John's wort: Used mainly as an antidepressant, this herb can interact with numerous other drugs.
Aloe: Sometimes marketed as an "internal" cleanser, aloe causes a strong cathartic effect in the intestines. That can lead to mineral depletion or worse if users have pre-existing intestinal issues, such as ulcerative colitis.
Cascara: An effective laxative but ineffective weight loss agent, cascara interacts with other drugs and can throw off the body's mineral balance.
Glucomannan: Derived from a plant root, glucomannan has been banned in several countries because when exposed to liquid it swells and can result in a gastrointestinal obstruction.
Guarana: A natural stimulant, guarana can increase blood pressure.
Yerba mate: Often used in a tea, yerba mate ingestion can result in high blood pressure and overstimulation of the central nervous system. It may also be linked to esophageal cancer.
Guar gum: It is used in the food and pharmaceutical industries as a thickening agent, but taken alone, guar gum can swell on contact with liquid, potentially leading to an obstruction.
Ephedra (ma huang): Consumers should not be able to find OTC supplements containing this ingredient, because the FDA banned its sale in dietary supplements in 2004. Use of ephedra can cause high blood pressure and other cardiovascular problems.
SOURCES: http://www.healthyweightforum.org (Healthy Weight Forum)Nutr Metab Cardiovasc Dis 2008 Feb; 18(2): 158-68 (website: http://www.ncbi.nih.nlm.gov)www.teachersdomain.org (Teachers Domain)www.fda.govwww.weightlossworld.orgwww.obesityaction.org (Obesity Action Council)www.dailymed.nlm.nih.gov (Daily Med)www.webmd.comwww.aarp.org (American Association of Retired Persons)www.pdrhealth.comNIH, Office of Dietary Supplements websiteOver-the-Counter and Herbal Remedies for Weight Loss https://www.webmd.com/diet/guide/herbal-remedies