Prescription and Over the Counter Diet Pills

Are you thinking about using an over-the-counter weight loss pill to slim down? Or perhaps you heard about an FDA-approved diet pill that requires a prescription. Trying to find a safe medication to help you slim down can be challenging. Use this guide to sort through the facts to find the best product for you.

How to Buy the Best Weight Loss Pill 

There are three different types of diet pills that you can buy. Prescription weight loss pills are medications that you would get through your doctor. Non-prescription or over-the-counter (OTC) diet pills are medications that don't require a prescription. And finally, there are herbal supplements for weight loss that you'll find in many vitamin shops and drug stores. Herbal supplements are not considered medications and therefore do not have to follow the strict guidelines for safety that govern our medicines.

The best resource for information regarding the use of any supplement or weight loss pill is your healthcare provider. Talk to your doctor about current research into the products that have grabbed your attention. Your doctor will also be able to discuss how taking a diet pill might interact with your other medications and will also be able to provide the best advice regarding the safety of new products.


  • Xenical (orlistat)

  • alli (orlistat) OTC

  • Qsymia (phentermine and topiramate)

  • Belviq (lorcaserin)

  • Saxenda (liraglutide [rDNA origin] injection) 

  • Contrave (naltrexone hydrochloride and bupropion hydrochloride)

  • Vyvanse (lisdexamfetamine dimesylate)

  • Phentermine

Herbs and Supplements

  • Garcinia cambogia

  • Glucomannan

  • Conjugated linoleic acid (CLA)

  • Raspberry ketones

  • Forskolin

  • Chromium

  • Green tea

  • Bee pollen

Prescription FDA-Approved Diet Pills 

  • Xenical (orlistat): This prescription medication has been approved by the U.S. Food and Drug Administration (FDA) since 1999. Xenical is a lipase inhibitor which means it works by blocking the absorption of fat. Dieters must follow a low-fat diet or they experience uncomfortable side effects.
  • Qsymia (phentermine and topiramate): The two drugs in Qsymia work together to suppress appetite and reduce your food intake. Your physician may prescribe it if you have a BMI over 30 or a body mass index of 27 and higher along with a weight-related condition such as type 2 diabetes or high blood pressure. The medication needs to be taken along with lifestyle modifications for sustained weight loss.
  • Belviq (lorcaserin): This diet pill works by activating serotonin receptors that regulate hunger. By helping to control your appetite, drug makers hope that Belviq will help you feel full after you've eaten less food. It is available with a prescription to patients with a BMI of 30 or a body mass index of 27 along with an obesity-related condition.
  • Saxenda (liraglutide [rDNA origin] injection): This injectable medication helps dieters to feel full sooner so that they eat less and lose weight. Saxenda can be used by patients who are obese (with a BMI of 30 or more) or by patients who have a BMI of 27 or more and a weight-related medical condition such as type 2 diabetes, high cholesterol or high blood pressure.
  • Contrave (naltrexone hydrochloride and bupropion hydrochloride): This weight loss drug affects the central nervous system to increase the number of calories you burn and reduce your appetite. The diet pill is prescribed along with a reduced-calorie diet and exercise program to help people lose weight.
  • Vyvanse (lisdexamfetamine dimesylate): This medication is FDA-approved for the treatment of a binge-eating disorder, but it is not approved for weight loss.
  • Phentermine: Phentermine is marketed under a long list of names, including Suprenza, Adipex-P, Kraftobese, and Teramine. It is prescribed only for short periods and works by decreasing a dieter's appetite. The drug can be habit-forming; side effects can include insomnia, constipation and dry mouth.

Meridia (sibutramine) is an appetite suppressant product that was removed from the market in the United States in 2010. The FDA initially approved the product, but the manufacturer stopped producing it after clinical studies showed that users had an increased risk of heart attack and stroke. The National Institutes of Health (NIH) recommends that anyone still using Meridia contact their physician to discuss alternative treatments.

The Worst and Best Over-the-Counter Diet Pills and Supplements

If you don't have a prescription for a diet medication, you might be tempted to take an over-the-counter weight loss pill or supplement. Keep in mind while OTC medications are FDA-approved for safety and effectiveness, weight loss supplements are not. The FDA relies on the company that makes them make sure that they are safe.

So when you buy a diet supplement or a popular herbal supplement for weight loss you need to be very careful about what you buy. The FDA also does not approve most of the claims that companies make about their products. In many cases, weight loss claims are carefully crafted to make the product sound more effective than it is.

  • alli (orlistat): This is the only over-the-counter weight loss pill approved by the FDA. It contains a lower dose of the same medication that is in Xenical. Dieters who take alli must limit fat intake and make lifestyle changes or they will experience uncomfortable side effects. alli was voluntarily removed from the market in 2014 after a tampering scare, but the company re-released the diet pill with a new tamper-evident package in 2015.
  • Garcinia cambogia: This natural weight loss supplement is derived from a fruit that grows in warmer climates. It is widely available at health food stores and from online vendors, but many of the claims made by sellers have not been backed up consistently in published medical literature. One study published in 2012 in Critical Reviews in Food Science and Nutrition said that there is still little evidence to support its effectiveness.
  • Glucomannan: The name of this popular diet supplement may not sound familiar but you've probably seen products that contain the fiber supplement. Lipozene for weight loss is one product that contains glucomannan. Unfortunately, research has been inconclusive and in 2017 the authors of a review published in Critical Reviews in Food Science and Nutrition were not been able to confirm that the fiber substance can help you lose weight.
  • Conjugated linoleic acid (CLA): This supplement has been studied extensively, but as of 2017, the weight loss results have been mixed. Check with your doctor before investing. Some dieters experienced increased insulin resistance and lower levels of HDL cholesterol when taking the diet pills.
  • Raspberry ketones: This weight loss supplement became popular after Dr. Oz mentioned it on his TV show. But there has been no evidence to support the claims that raspberry ketones can help humans lose weight.
  • Forskolin: This natural extract from the coleus plant is advertised as a diet supplement and fat blocker. But according to the 2017 review published in Critical Reviews in Food Science and Nutrition, there is very little evidence to support its use as a weight-loss supplement.
  • Chromium: Sometimes marketed as chromium picolinate, products that contain this substance often claim to help you burn extra calories and decrease your appetite. However, the NIH found that chromium has no significant benefits for weight loss. Chromium is generally considered to be safe, but it is likely to drain your wallet without any significant benefit to your waistline.
  • Green tea: Green tea can be consumed as a beverage or in pill form. It is often used to aid in weight loss or for improving mental alertness or lowering blood pressure. While green tea is safe when consumed in moderation, there is little evidence to support its use as a long-term weight loss supplement.
  • Hoodia: This herb is sold as a hunger suppressant for dieters. Hoodia is extracted from a flowering plant and can be consumed in tablet, pill or powder form. A review published in 2019 reports there is no scientific evidence to support the claims that hoodia is an effective appetite suppressant and its safety has not been verified.
  • Bee pollen: There is little evidence to support the use of bee pollen for weight loss. In 2014, one company was cited by the Centers for Disease Control for making false and misleading claims about the supplement's effects.

Ephedra or Bitter Orange: When ephedra was banned from the market in 2004, a number of similar stimulants took its place. Most advertise that they are ephedra-free and safe for dieters. They often contain bitter orange (citrus aurantium), synephrine or octopamine. Two of the most popular products, Xenadrine EFX and Advantra Z, were tested by researchers in 2005 and still found to have unsafe effects on heart rate and blood pressure.

If the over the counter diet pill or weight loss supplement that you are interested in is not listed above, visit the National Institutes of Health Dietary Supplement Fact Sheets website. The NIH provides a comprehensive list of diet supplements along with current information about safety and effectiveness. And remember to talk to your doctor about any diet pill or weight loss supplement that you are considering.

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