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Prescription Medications to Treat Overweight & Obesity

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What are overweight and obesity?

Health care professionals use the Body Mass Index (BMI), a measure of your weight in relation to your height, to define overweight and obesity.

People who have a BMI between 25 and 30 are considered to be overweight. Obesity is defined as having a BMI of 30 or greater. You can calculate your BMI to learn if you are overweight, have obesity, or have severe obesity, which may increase your risk of health problems. Your health care professional can assess your individual risk caused by your weight.

If you are struggling with your weight, a healthy eating plan and regular physical activity may help you lose weight and keep it off over the long term. If these lifestyle changes are not enough to help you lose weight or maintain your weight loss, your health care professional may prescribe medications as part of your weight-control program.

How common are overweight and obesity?

Obesity is a chronic disease that affects more than 4 in 10 adults in the United States, and nearly 1 in 10 Americans have severe obesity.1

How do weight management medications work?

Prescription medications to treat overweight and obesity work in different ways. For example, some medications may help you feel less hungry or full sooner. Other medications may make it harder for your body to absorb fat from the foods you eat.

Who might benefit from weight management medications?

Weight management medications are meant to help people who have health problems related to overweight or obesity. Health care professionals use BMI to help decide whether you might benefit from weight management medications. Your health care professional may prescribe a medication to treat your overweight or obesity if you are an adult with

Weight management medications aren’t for everyone with a high BMI. If you are overweight or have obesity, you might be able to lose weight with a lifestyle program that changes your behaviors and improves your eating and physical activity habits. A lifestyle program may also address other things that cause you to gain weight, such as eating triggers and not getting enough sleep.

Can children or teenagers take weight management medications?

Most of the weight management medications approved by the U.S. Food and Drug Administration (FDA) are for adults only. Two prescription medications, orlistat (Xenical)2 and liraglutide (Saxenda),3 are approved by the FDA for children ages 12 and older. A third prescription medication, setmelanotide (IMCIVREE),4 is approved by the FDA for children ages 6 years and older who have rare genetic disorders causing obesity.

Can medications replace physical activity and healthy eating habits as a way to lose weight?

Medications don’t replace physical activity or healthy eating habits as a way to lose weight. Studies show that weight management medications work best when combined with a lifestyle program. Ask your health care professional about lifestyle treatment programs for weight management that will work for you.

Two women walking down a paved road with earbuds in their ears.Weight management medications don’t replace physical activity and healthy eating habits.

What are the benefits of using prescription medications to lose weight?

When combined with changes to behavior, including healthy eating and increased physical activity, prescription medications help some people lose weight and maintain weight loss. On average, after 1 year, people who take prescription medications as part of a lifestyle program lose 3% to 12% more of their starting body weight than people in a lifestyle program who do not take medication.

Research shows that some people taking prescription weight management medications lose 10% or more of their starting weight.5 Results vary by medication and by person.

Weight loss of 5% to 10% of your starting body weight may help improve your health by lowering blood sugar, blood pressure, and triglyceride levels. Losing weight also can improve some other health problems related to overweight and obesity, such as joint pain and sleep apnea. Most weight loss takes place within the first 6 months of starting the medication.

What are the concerns about using prescription medications to lose weight?

Experts are concerned that, in some cases, the side effects of prescription medications that treat overweight and obesity may outweigh the benefits. For this reason, never take a weight management medication only to improve the way you look. In the past, some weight management medications were linked to serious health problems, and they were removed from U.S. markets.

Possible side effects vary by medication and how it acts on your body. Most side effects are mild and most often improve if you continue to take the medication. Rarely, serious side effects can occur.

Tips for taking weight management medication

  • Follow your health care professionals instructions about weight management medications.
  • Buy your medication from a pharmacy or online distributor approved by your health care professional.
  • Only take weight management medication to support your healthy eating and physical activity program.
  • Know the side effects and warnings before taking any medication.
  • If you are not losing weight after 12 weeks on the full dose of your medication, ask your health care professional whether you should stop taking it.
  • Talk with your health care professional about any other medications you are taking, including supplements and vitamins, when considering weight management medications.
  • Never take weight management medications during pregnancy or if you are planning a pregnancy.

Which weight management medication might work for me?

Choosing a medication to treat overweight or obesity is a decision between you and your health care professional. Important factors to consider include

  • the likely benefits of weight loss
  • the medication’s possible side effects
  • your current health issues and other medications
  • your family’s medical history
  • cost

How long will I need to take weight management medication?

How long you will need to take weight management medication depends on whether the drug helps you lose weight and keep it off and whether you experience serious side effects.

If you have lost enough weight to improve your health and are not experiencing serious side effects, your health care professional may advise you to stay on the medication indefinitely. If you do not lose at least 5% of your starting weight after 12 weeks on the full dose of your medication, your health care professional will probably advise you to stop taking it. Your health care professional may also

  • change your treatment plan or consider using a different weight management medication
  • have you try different lifestyle, physical activity, or eating programs
  • change your other medications that might be causing weight gain
  • refer you to a bariatric surgeon to see if weight-loss (bariatric) surgery  might be an option for you

Because obesity is a chronic disease, you may need to continue your new eating and physical activity habits and other behaviors for years—or even a lifetime—to improve your health and maintain a healthier weight.

Will I regain some weight after I stop taking weight management medication?

You probably will regain some weight after you stop taking weight management medication. Developing and maintaining healthy eating habits and increasing physical activity may help you regain less weight or keep it off.

Federal physical activity guidelines (PDF, 14.5 MB) recommend at least 150 minutes a week of moderate-intensity aerobic activity and at least 2 days a week of muscle-strengthening activities. You may need to do more than 300 minutes of moderate-intensity activity a week to reach or maintain your weight-loss goal.

Will insurance cover the cost of weight management medication?

Some, but not all, insurance plans cover medications that treat overweight and obesity. Contact your insurance provider to find out if your plan covers these medications.

What medications are available to treat overweight and obesity?

The table below lists prescription drugs approved by the FDA for weight loss. The FDA has approved five of these drugs—orlistat (Xenical, Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda), and semaglutide (Wegovy)—for long-term use. A sixth approved drug, setmelanotide (IMCIVREE), is limited to people who have been diagnosed with one of three specific rare genetic disorders, which must be confirmed by genetic testing. You can keep taking these medications as long as you are benefiting from treatment and not experiencing serious side effects.

Some weight management medications that curb appetite are approved by the FDA for short-term use only, for up to 12 weeks. Although some health care professionals prescribe them for longer periods, not many research studies have looked at how safe and effective they are for long-term use.

Never take weight management medications if you are pregnant. If you are planning to get pregnant, you should also avoid these medications, as some of them may harm the fetus.

Prescription medications approved to treat overweight and obesity

Weight Management Medication Approved For How It Works Common Side Effects Warnings
orlistat (Xenical)

Available in lower dose without prescription (Alli)
Adults and children ages 12 and older Works in your gut to reduce the amount of fat your body absorbs from the food you eat
  • diarrhea
  • gas
  • leakage of oily stools
  • stomach pain
  • Rare cases of severe liver injury have been reported
  • Avoid taking with cyclosporine
  • Take a multivitamin pill daily to make sure you get enough of certain vitamins that your body may not absorb from the food you eat
phentermine-topiramate (Qsymia) Adults
  • A mix of two medications: phentermine, which lessens your appetite, and topiramate, which is used to treat seizures or migraine headaches
  • May make you less hungry or feel full sooner
  • constipation
  • dizziness
  • dry mouth
  • taste changes, especially with carbonated beverages
  • tingling of your hands and feet
  • trouble sleeping
  • Do not use if you have glaucoma or hyperthyroidism
  • Tell your health care professional if you have had a heart attack or stroke, abnormal heart rhythm, kidney disease, or mood problems
  • MAY LEAD TO BIRTH DEFECTS—DO NOT TAKE PHENTERMINE-TOPIRAMATE IF YOU ARE PREGNANT OR ARE PLANNING A PREGNANCY
  • Do not take if you are breastfeeding
naltrexone-bupropion (Contrave) Adults
  • A mix of two medications: naltrexone, which is used to treat alcohol and drug dependence, and bupropion, which is used to treat depression or help people quit smoking
  • May make you feel less hungry or full sooner
  • constipation
  • diarrhea
  • dizziness
  • dry mouth
  • headache
  • increased blood pressure
  • increased heart rate
  • insomnia
  • liver damage
  • nausea
  • vomiting
  • Do not use if you have uncontrolled high blood pressure, seizures, or a history of anorexia or bulimia nervosa
  • Do not use if you are dependent on opioid pain medications or are withdrawing from drugs or alcohol
  • Do not use if you are taking bupropion (Wellbutrin, Zyban)
  • MAY INCREASE SUICIDAL THOUGHTS OR ACTIONS
liraglutide (Saxenda)

Given daily by injection
Adults and children ages 12 years and older
  • Mimics a hormone called glucagon-like peptide-1 (GLP-1) that targets areas of the brain that regulate appetite and food intake
  • At a lower dose under a different name, Victoza, this drug was FDA-approved to treat type 2 diabetes
  • nausea
  • diarrhea
  • constipation
  • abdominal pain
  • headache
  • increased heart rate
  • May increase the chance of developing pancreatitis
  • Has been found to cause a rare type of thyroid tumor in animals
semaglutide (Wegovy)6

Given weekly by injection
Adults
  • Mimics a hormone called glucagon-like peptide-1 (GLP-1) that targets areas of the brain that regulate appetite and food intake
  • Under different names and dosages, this drug was FDA-approved to treat type 2 diabetes as an injectable medication (Ozempic) and as an oral pill (Rybelsus)
  • nausea
  • diarrhea
  • vomiting
  • constipation
  • abdominal (stomach) pain
  • headache
  • fatigue
  • Do not use in combination with other semaglutide-containing products, other GLP-1 receptor agonists, or other products intended for weight loss, including prescription drugs, over-the-counter drugs, or herbal products
  • May increase the chance of developing pancreatitis
  • Has been found to cause a rare type of thyroid tumor in animals
setmelanotide (IMCIVREE)

Available by injection only
People ages 6 years and older with obesity due to three specific rare genetic conditions only
  • May reduce appetite and increase feeling of fullness
  • May increase resting metabolism (how the body burns calories)
  • Although it can help a person lose weight, it does not treat the genetic defects
  • injection site reaction
  • skin darkening
  • nausea
  • disturbance in sexual arousal
  • depression and suicidal ideation
  • risk of serious adverse reactions in neonates and infants with low birthweight, owing to benzyl alcohol preservative
Only for people with any of these ultra-rare genetic diseases, confirmed by genetic testing
  • proopiomelanocortin (POMC) deficiency
  • proprotein convertase subtilisin/kexin type 1 (PCSK1) deficiency
  • leptin receptor (LEPR) deficiency
Do not use while pregnant or breastfeeding.
(Other medications that curb your desire to eat include)
  • phentermine
  • benzphetamine
  • diethylpropion
  • phendimetrazine
Adults
  • Increases chemicals in your brain to make you feel you are not hungry or that you are full
  • Note: FDA-approved only for short-term use—up to 12 weeks
  • dry mouth
  • constipation
  • difficulty sleeping
  • dizziness
  • feeling nervous
  • feeling restless
  • headache
  • raised blood pressure
  • increased heart rate
  • Do not use if you have heart disease, uncontrolled high blood pressure, hyperthyroidism, or glaucoma
  • Tell your health care professional if you have severe anxiety or other mental health problems

How do health care professionals use prescription medications “off-label” to treat overweight and obesity?

Sometimes health care professionals use medications in a way that’s different from what the FDA has approved. That’s called “off-label” use. By choosing an off-label medication to treat overweight and obesity, your health care professional may prescribe

  • a drug approved for treating a different medical problem
  • two or more drugs at the same time
  • a drug for a longer time period than approved by the FDA

You should feel comfortable asking whether your health care professional is prescribing a medication that is not approved for treating overweight and obesity. Before using a medication, learn all you need to know about it.

What other medications for weight loss may be available in the future?

Researchers are currently studying several new medications and combinations of medications in animals and people. Researchers are working to identify safer and more effective medications to help people who are overweight or have obesity lose weight and maintain a healthy weight for a long time.

Future drugs may use new strategies, such as

  • regulating several gut hormones at the same time
  • targeting specific genes that cause obesity
  • allowing people to lose body fat without losing muscle during weight loss
  • changing bacteria in the gut to control weight

Clinical Trials for Prescription Medications to Treat Overweight and Obesity

The NIDDK conducts and supports clinical trials in many diseases and conditions, including overweight and obesity. The trials look to find new ways to prevent, detect, or treat disease and improve quality of life.

What are clinical trials for prescription medications to treat overweight and obesity?

Clinical trials—and other types of clinical studies—are part of medical research and involve people like you. When you volunteer to take part in a clinical study, you help health care professionals and researchers learn more about disease and improve health care for people in the future.

Researchers are studying many aspects of prescription medications to treat overweight or obesity, such as

  • the effect of the FDA-approved medication liraglutide (Saxenda, Victoza) on weight loss and gastric functions (stomach emptying effect) in people who are overweight or have obesity
  • adolescents and young adults who don’t achieve expected weight loss or who still have severe obesity after undergoing weight-loss surgery
  • patients who have obesity and binge-eating disorder
  • women who are overweight or have obesity and polycystic ovary syndrome

Find out if clinical studies are right for you.

Watch a video of NIDDK Director Dr. Griffin P. Rodgers explaining the importance of participating in clinical trials.

What clinical studies for prescription medications to treat overweight and obesity are looking for participants?

You can view a filtered list of clinical studies on prescription medications to treat overweight and obesity that are federally funded, open, and recruiting at www.ClinicalTrials.gov. You can expand or narrow the list to include clinical studies from industry, universities, and individuals; however, the NIH does not review these studies and cannot ensure they are safe. Always talk with your health care provider before you participate in a clinical study.

References

[1] Hales CM, Carroll MD, Fryar CD, Ogden CL. Prevalence of obesity and severe obesity among adults: United States, 2017–2018. NCHS Data Brief 360. National Center for Health Statistics; 2020. Accessed December 7, 2020. www.cdc.gov/nchs/products/databriefs/db360.htm

[2] Weight-loss medicines. MedlinePlus, U.S. National Library of Medicine. Updated May 21, 2017. Accessed January 31, 2019. https://medlineplus.gov/ency/patientinstructions/000346.htm

[3] U.S. Food & Drug Administration. FDA approves weight management drug for patients aged 12 and older. Updated December 4, 2020. Accessed June 7, 2021. www.fda.gov/drugs/drug-safety-and-availability/fda-approves-weight-management-drug-patients-aged-12-and-older

[4] U.S. Food & Drug Administration. FDA approves first treatment for weight management for people with certain rare genetic conditions. Updated November 27, 2020. Accessed June 7, 2021. www.fda.gov/drugs/drug-safety-and-availability/fda-approves-first-treatment-weight-management-people-certain-rare-genetic-conditions

[5] Yanovski SZ, Yanovski JA. Long-term drug treatment for obesity: A systematic and clinical review. JAMA. 2014;311(1):74–86. doi:10.1001/jama.2013.281361

[6] FDA approves new drug treatment for chronic weight management, first since 2014. News release. U.S. Food & Drug Administration. June 4, 2021. www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014

Last Reviewed June 2021
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Kishore Gadde, M.D., Pennington Biomedical Research Center