Weight-loss medicines
Prescription weight loss drugs; Diabetes - weight loss drugs; Obesity - weight loss drugs; Overweight - weight loss drugs
Medicine Options
Several weight-loss medicines are available in the United States. The amount of weight you are likely to lose with these medicines varies greatly from as little as 5 to 10 pounds (lbs) (2 to 4.5 kilograms [kg]) to 20% of your body weight or more. But not everyone loses weight while taking them.
Most people will regain some or all of the weight after they stop taking the medicines, unless they have made lasting lifestyle changes. These changes include exercising more, cutting unhealthy foods from their diets, and reducing the total amount they eat.
You may also see ads for herbal remedies and supplements that claim to help you lose weight. Many of these claims are not true. Some of these supplements can have serious side effects.
Note for women: Pregnant or nursing women should never take diet medicines. This includes prescription, herbal, and over-the-counter remedies. Over-the-counter refers to medicines, herbs, or supplements you can buy without a prescription.
The different weight-loss medicines are described below. Be sure to talk with your provider about which medicine is right for you.
ORLISTAT (XENICAL AND ALLI)
Orlistat works by slowing the absorption of fat in the intestine by about 30%. It is approved for long-term use.
About 6 lbs (3 kg) or up to 6% of body weight can be lost when using this medicine. But not everyone loses weight while taking it. Many people regain most of the weight within 2 years after they stop using it.
The most unpleasant side effect of orlistat is oily diarrhea that may leak from the anus. Eating fewer fatty foods can reduce this effect. Despite this side effect, most people tolerate this medicine.
Xenical is the brand of orlistat your provider can prescribe for you. You can also buy orlistat without a prescription under the name Alli. These pills are half the strength of Xenical. Orlistat costs about $100 or more a month. Consider whether the cost, side effects, and the small weight loss you can expect are worth it to you.
Your body may not absorb important vitamins, minerals, and other nutrients from food while you are using orlistat. You should take a daily multivitamin if you use orlistat.
MEDICINES THAT SUPPRESS THE APPETITE
These medicines work in your brain and, in some cases, your gastrointestinal tract to make you less interested in food and more satisfied with eating less.
Not everyone loses weight while taking the medicines. Most people will regain some or all of the weight after they stop taking the medicines, unless they have made lasting lifestyle changes. Talk with your provider about how much weight you can expect to lose by taking any of these medicines.
These medicines are available only by prescription. They include:
- Benzphetamine, Phendimetrazine (Bontril PDM)
- Diethylpropion (Tepanil Ten-Tab)
- Liraglutide (Saxenda)
- Naltrexone combined with bupropion (Contrave)
- Phentermine (Adipex-P, Lomaira, Phentercot, Pro-Fast)
- Phentermine combined with topiramate (Qsymia)
- Semaglutide (Wegovy)
- Setmelanotide (Imcivree)
- Tirzepatide (Zepbound)
Side Effects
Be sure you understand the side effects of weight-loss medicines. Side effects can include:
- Increase in blood pressure
- Problems sleeping, headache, nervousness, and palpitations
- Nausea, constipation, and dry mouth
- Depression, which some people who are obese struggle with already
If You Have Diabetes
If you have diabetes that needs treatment with medicines, you may want to ask your provider about diabetes medicines that often lead to weight-loss. These include:
- Canagliflozin (Invokana)
- Dapagliflozin (Farxiga)
- Dapagliflozin combined with saxagliptin (Qtern)
- Dulaglutide (Trulicity)
- Empagliflozin (Jardiance)
- Exenatide (Byetta, Bydureon)
- Liraglutide (Victoza)
- Lixisenatide (Adlyxin)
- Metformin (Glucophage, Glumetza, and Fortamet)
- Semaglutide (Ozempic)
- Tirzepatide (Mounjaro)
Of these medicines, liraglutide (as Saxenda), semaglutide (as Wegovy), and tirzepatide (as Zepbound) are approved by the FDA to treat weight-loss in people without diabetes.
References
Hafida S, Apovian CM. Obesity and neuroendocrine control of energy stores. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 40.
Jensen MD, Bessesen DH. Obesity. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 201.
Keating MK, Woodruff RK, Saner EM. Management of obesity: office-based strategies. Am Fam Physician. 2024;110(2):145-156. PMID: 39172672.
National Institutes of Diabetes and Digestive and Kidney Diseases website. Prescription medications to treat overweight & obesity.
Version Info
Last reviewed on: 7/3/2025
Reviewed by: Linda J. Vorvick, MD, Clinical Professor Emeritus, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
