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decision pointShould I use over-the-counter diet aids?

Many people seek help to lose weight. And there are many weight-loss products for sale without a prescription (over the counter) at drugstores and supermarkets and over the Internet. Consider the following when making your decision:

  • No over-the-counter diet aids have been proven to be both safe and effective for everyone.
  • When a diet aid does work, it’s usually because the person followed the manufacturer’s recommendations to follow a healthy eating plan and get more exercise while taking the supplement.
  • It's wise to talk to your doctor before taking any over-the-counter diet aid.
  • Most diet aids and other supplements that you can buy over the counter are not regulated, so makers can make any claims they want to about how well their products work.
  • Are you at a healthy weight? If you are, you're better off forgetting about weight loss. Instead, learn healthy eating and activity habits that will help you stay at a healthy weight. For more information, see the topic Weight Management.

Are you at a healthy weight?

Before you consider whether to use any over-the-counter diet aid, find out if you really need to lose weight. A healthy weight is the weight you reach when you're active and eating right. Many people who carry around a few extra pounds are still at a healthy weight.

If you practice healthy eating habits and are active enough to stay healthy, then a few extra pounds is not bad for your health unless you have other medical problems. On the other hand, dieting can be bad for your health. Diets almost never work, and they can cause many people to fall into an unhealthy cycle of losing and gaining weight. This is often called "yo-yo dieting." Yo-yo dieting may be harder on the body than just being overweight.

If you are thinking about losing weight, ask your doctor whether it's a good idea for you.

What are over-the-counter diet aids?

There are many products for weight loss that you can buy without a prescription at drugstores and supermarkets and over the Internet. Many of these have never been proven to work, and those that do work usually come with warnings.

See a list of popular over-the-counter diet aids.

What about Alli?

Alli (say "AL-eye") is a lower-dose version of the prescription drug orlistat (Xenical), which is used to treat obesity. You can buy Alli without a prescription.

Orlistat has been proven to help people lose weight.1 It works by preventing fat absorption, so that the fat you eat moves through your intestines undigested. But the weight loss amounts to only a few pounds, and the drug's side effects can be very unpleasant.

The side effects include sudden loose stools and oily spotting on your underwear. The more fat you eat, the worse the side effects are, so it's best to avoid fat while you are taking this drug.

Do not take Alli if you:

  • Have had an organ transplant.
  • Are pregnant or breast-feeding.

Talk to your doctor before you take Alli, but especially if you:

  • Take blood-thinning medicines.
  • Have diabetes or thyroid disease.

What are the risks or side effects of over-the-counter diet aids?

Most over-the-counter diet aids don't have to pass government tests for safety or effectiveness.

Long-term studies are the only way to tell whether a medicine or supplement works and is safe. And there are very few such studies of diet aids. But we know about the following risks:

  • Over-the-counter appetite suppressants shouldn't be used by people who have heart disease, high blood pressure, diabetes, kidney problems, thyroid problems, glaucoma, or depression.
  • Appetite suppressants are only intended for use for a short time (8 to 12 weeks). But staying at a healthy weight is a lifelong effort. It is costly and possibly dangerous to depend on these medicines to control your weight for long periods of time. If you are going to use these drugs to help you lose weight, be sure to also make healthy changes to your diet and get regular exercise.
  • Water-loss pills (diuretics, such as Aqua-Ban) only get rid of water and do not reduce the amount of fat in your body. Using water-loss pills to lose weight is not recommended and can be dangerous.
  • Because diet supplements are not regulated, manufacturers sometimes make claims that aren't true. For example, just because the label says the supplement is "all natural" doesn't mean it’s safe. Many things that are "natural" can still hurt you. And manufacturers may cite only their own studies to show how well their products work.
  • Many products contain 20 or more ingredients, so it’s really hard to know how all the ingredients will interact with each other in your body and how they will interact with any other medicines or supplements you may be taking.
  • You shouldn't take cough or cold medicines while you take some of these diet pills. They contain some of the same medicine, and you could get too much. Ask your pharmacist if it's safe to take cold medicine with the diet pills you are taking.

The U.S. Food and Drug Administration (FDA) has banned the sale of ephedra because of concerns about safety. The product has been linked to heart attacks, strokes, and some deaths. Ephedra and ephedrine-the active ingredient in ephedra-decrease appetite by increasing metabolic rate.

It's wise to talk to your doctor before you take any over-the-counter diet aid.

Why might my doctor recommend an over-the-counter diet aid?

Your doctor is not likely to recommend that you use an over-the-counter diet aid in your efforts to reach a healthy weight and stay there. The best way to get to a healthy weight and stay there is to eat right and exercise regularly.

If you need more information, see the topic Weight Management.

Your choices are:

  • Use an over-the-counter diet aid to help you lose weight.
  • Get to a healthy weight by eating right and exercising.

The decision whether to take over-the-counter diet aids takes into account your personal feelings and the medical facts.

Reasons to take over-the-counter diet aids

Reasons not to take diet aids

  • Some diet aids may help you feel less hungry so that you do not eat so much.
  • Studies show that Alli helps some people lose a small amount of weight.

Are there other reasons you might want to use over-the-counter diet aids?

  • There is no proof that most over-the-counter diet aids work.
  • When a diet aid does work, it’s usually because you followed the manufacturer’s recommendations to improve your eating and exercise habits while taking the supplement.
  • The few diet aids that work often come with warnings. You shouldn't use them if you have heart disease, high blood pressure, diabetes, kidney problems, thyroid problems, glaucoma, or depression. Using water-loss pills to lose weight can be dangerous.

Are there other reasons you might not want to use diet aids?

These personal stories may help you make your decision.

Use this worksheet to help you make your decision. After completing it, you should have a better idea of how you feel about over-the-counter diet aids. Discuss the worksheet with your doctor.

Circle the answer that best applies to you.

I'm desperate, and even though I know these don't usually work, I have to try something else. Yes No Unsure
I don't want to spend extra money on diet pills that may not work. Yes No Unsure
I want to use a diet aid with my doctor monitoring my progress and side effects. Yes No Unsure
I'm afraid of using any supplements because of unknown potential side effects. Yes No Unsure

Use the following space to list any other important concerns you have about this decision.






What is your overall impression?

Your answers in the above worksheet are meant to give you a general idea of where you stand on this decision. You may have one overriding reason to use or not use over-the-counter diet aids.

Check the box below that represents your overall impression about your decision.

Leaning toward using over-the-counter diet aids


Leaning toward NOT using over-the-counter diet aids



  1. Rucker D, et al. (2007). Long term pharmacotherapy for obesity and overweight: Updated meta-analysis. BMJ. Published online November 15, 2007 (doi:10.1136/bmj.39385.413113.25).

Author Cynthia Tank
Editor Katy E. Magee, MA
Associate Editor Michele Cronen
Primary Medical Reviewer Martin Gabica, MD - Family Medicine
Primary Medical Reviewer Ruth Schneider, MPH, RD - Diet and Nutrition
Specialist Medical Reviewer Rhonda O'Brien, MS, RD, CDE - Diabetes Educator
Last Updated January 14, 2010

WebMD Medical Reference from Healthwise

Last Updated: January 14, 2010
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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