Pros and cons of weight loss drugs (2023)

Prescription drugs for weight loss

Study the pros and cons of medications used to treat obesity.

By the staff at the Mayo Clinic

Are you an adult with serious health problems due to your weight? Have you tried diet and exercise but failed to lose enough weight? If you answered yes to these questions, a prescription weight loss medication may be a choice for you.

Prescription drugs are drugs that a doctor prescribes for you. You cannot buy them off the shelf of a pharmacy like you can buy over-the-counter medications.

Just know that you need to use prescription weight loss medications in addition to - not in place of - a healthy diet and exercise.

Who can take medicine to lose weight?

Your doctor may suggest a weight loss medication in some cases. This includes if you haven't been able to lose weight with diet and exercise and if you:

  • Body mass index (BMI) is greater than 30. This means that you live with a condition associated with excess body fat called obesity.
  • IMCis greater than 27. You also have a serious obesity-related medical condition, such as B. Diabetes or high blood pressure.

Before choosing a medication for you, your doctor will think about your history and any health problems you may have. Then your doctor will talk with you about the pros and cons of prescription weight loss medications.

These drugs are not for everyone. For example, you shouldn't take prescription weight loss medications if you're trying to get pregnant, pregnant, or breastfeeding.

How well do weight loss drugs work?

Prescription weight-loss medication that you can take for more than 12 weeks, known as long-term use, results in significant weight loss compared to an inactive, drug-free regimen known as a placebo. Combining weight loss medications and lifestyle changes results in greater weight loss than lifestyle changes alone.

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Taking these medications for one year can result in a total body weight loss of 3% to 12% more than weight loss with lifestyle changes alone. That doesn't sound like much. But losing 5% to 10% of your total weight and keeping it off can have important health benefits. For example, it can lower blood pressure, blood sugar levels, and levels of blood fats called triglycerides.

What you should know about weight loss drugs

Mild side effects such as nausea, constipation, and diarrhea are common. They can decrease over time. Serious side effects can rarely occur. Therefore, it is important to ask your doctor about all treatment options. And ask about the potential benefits and risks of each drug.

Weight loss drugs can be expensive and are not always covered by insurance. Ask your insurance company about your insurance coverage.

Many people regain some of the weight they lost when they stop taking weight loss medications. But practicing healthy lifestyle habits can help limit weight gain.

How long should I take a weight loss medication?

How long you take a weight loss drug depends on whether the drug helps you lose weight. If you've lost enough weight to improve your health and haven't experienced any serious side effects, your doctor may suggest that you take the drug long-term.

If you haven't lost at least 5% of your body weight after taking a full dose of a medication for 3 to 6 months, your doctor will likely change your treatment. They may switch to another weight loss medication.

What drugs are approved for weight loss?

Six weight loss drugs have been approved by the US. Food and Drug Administration (FDA) approved for long-term use:

  • Bupropion-Naltrexon (Contrave)
  • Liraglutide (Saxenda)
  • Orlistate (Xenical, Alli)
  • Phentermin-Topiramat (Qsymia)
  • Semaglutida (Wegovy)
  • Setmelanotida (Imcivree)

Most prescription weight loss medications make you feel less hungry or satiated. Some do both. The exception is orlistat. This affects the way your body absorbs fat.


Bupropion-Naltrexone is a combination drug. Naltrexone is used to treat alcohol and opioid addiction. Bupropion is a drug used to treat depression called an antidepressant and a drug that helps people stop smoking called a stop smoking aid. Like all antidepressants, bupropion carries a suicide risk warning. Bupropion-naltrexone can increase blood pressure. Therefore, your doctor should check your blood pressure regularly at the start of treatment. Common side effects include nausea, headache and constipation.


Liraglutide is also used to treat diabetes. It is given as a daily injection. Nausea is a common complaint. Vomiting may limit its use.

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You can also get Orlistat in reduced form (Alli) without a prescription. Orlistat can cause side effects such as gas and loose stools. You must be on a low-fat diet when taking this medication. In rare cases, severe liver damage has occurred with orlistat. But researchers haven't found that the drug causes liver damage.


Phentermine topiramate is a combination of a weight loss drug called phentermine and an anticonvulsant called topiramate. Phentermine can be abused as it acts like a stimulant called amphetamine. Other possible side effects include increased heart rate and blood pressure, insomnia, constipation, and nervousness. Topiramate increases the risk of birth defects.

Phentermine itself (Adipex-P, Lomaira) is also used for weight loss. It is one of four similar weight-loss drugs approved for less than 12 weeks, known as short-term use. The other drugs in this group are not often prescribed.


Semaglutide is also used to control type 2 diabetes. They take this as a weekly injection to control obesity.

It can cause side effects such as:

  • nausea and vomit
  • Diarrhea
  • stomachache
  • Headache
  • fatigue


OFDAapproved setmelanotide only for people aged 6 years and older who have obesity due to one of these rare inherited disorders:

  • Pro-Opiomelanocortina-Mangel
  • Proprotein-Subtilisin-Kexin-Mangel Type 1
  • Leptinrezeptormangel

To take the drug, you need test results that show you have one of these conditions. Setmelanotide does not treat any of the genetic problems that cause these disorders. But it can help with weight loss. It can decrease your appetite and make you feel fuller. And it can help you burn calories while your body is at rest.

You take setmelanotide as a daily injection. It can cause side effects such as:

  • Swollen or irritated skin at the needle insertion site
  • darker skin patches
  • nausea
  • Diarrhea
  • stomachache
  • unwanted sexual reactions
  • Depression
  • suicidal thoughts

Never give setmelanotide to a child under 6 years of age. May cause dangerous reactions in newborns and infants.

the end result

Weight loss drugs are not an easy answer to weight loss. But they can help you make the lifestyle changes you need to practice in order to lose weight and improve your health.

(Video) wegovy - WEIGHT LOSS Drug Miracle?? (Semaglutide Obesity Treatment) FDA Approved 2023

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October 29, 2022

  1. Ask MayoExpert. Weight control (adults). Mayo Clinic; 2018
  2. Ask MayoExpert. obesity (adult). Mayo Clinic; 2018
  3. Pilitsi E et al. Obesity pharmacotherapy: Available and studied drugs. Metabolism. 2019; doi:10.1016/j.metabol.2018.10.010.
  4. Perreault L. Obesity in adults: drug therapy. Accessed on October 12, 2020.
  5. Prescription drugs used to treat overweight and obesity. National Institute of Diabetes and Digestive and Kidney Diseases. Accessed August 23, 2018.
  6. Melmed S et al. Obesity. In: Williams Textbook of Endocrinology. 14th Elsevier Edition; 2020. Accessed on October 12, 2020.
  7. Patel K. Treatment of obesity: a focus on weight management pharmacotherapy. 2020; doi:10.1097/NOR.0000000000000643.
  8. Papadakis MA, et al., editors Obesity. In: Current Medical Diagnosis & Treatment 2021. 60th ed. McGraw-Hill; 2021. Accessed October 21,
  9. Shah M (expert opinion). Mayo Clinic. October 16, 2020.
  10. Apovian CM, et al. Pharmacologic management of obesity: an Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology and Metabolism. 2015; doi:10.1210/jc.2014-3415.
  11. FDA Drug Safety Advisory: Safety Review of Xenical/Alli (Orlistat) and Severe Liver Injury Completed. US Food and Drug Administration. Wound. Accessed on October 16, 2020.
  12. Wegovy (prescribing information). Novo Nordisk; 2022. Accessed on October 21, 2022.
  13. Imcivree (prescribing information). rhythm pharmaceuticals; 2022. Accessed on October 21, 2022.

For more information, see

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  1. The Mayo Clinic Diet online
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See too

  1. Alli weight loss pill
  2. Apple vinegar
  3. Bariatric surgery
  4. Desvio Biliopankreatische mit Duodenal Switch (BPD/DS)
  5. Dietary supplements for weight loss
  6. Endoscopic intragastric balloon
  7. endoscopic gastroplasty
  8. Endoscopic vertical gastroplasty (stomach sleeve)
  9. Magenbypass (Roux-en-Y)
  10. weight loss surgery
  11. Magenballon
  12. Phentermine for weight loss
  13. protein shakes
  14. Biliopankreatische Bypass with Duodenal Switch
  15. Roux-en-Y-Magenbypass
  16. Manga Gastrektomie
  17. Vitamin B-12 Injections
  18. natural diuretics
  19. weight loss surgery



What are the cons of fat loss pills? ›

National Institutes of Health

Pills that speed up the metabolism and suppress the appetite are risky and can lead to high blood pressure, fast heart rate and lung and heart problems. Some other possible side effects are: Bloating. Diarrhea.

What are the pros of weight loss pills? ›

The combination of weight-loss medicine and lifestyle changes leads to greater weight loss than do lifestyle changes alone. Taking these drugs for a year can mean a loss of total body weight of 3% to 12% more than that lost with lifestyle changes alone.

Is weight loss medicine good for health? ›

The weight-loss drugs won't melt off the pounds overnight. When they are successful, they result in an average weight loss of about 5% over a period of six to 12 months. However, even that modest weight loss can improve your health and reduce your risk of heart disease, stroke, and diabetes.

What are the pros and cons of losing weight? ›

Quick weight loss can be inspiring, but it increases your risk of health conditions including gallstones, fatigue and malnutrition. On the flip side, losing weight slowly and keeping it off for years can decrease your risk of serious conditions like high blood pressure, heart disease, diabetes and cancer.

How do I ask my doctor for weight loss pills? ›

Some helpful tips when speaking to your doctor:
  1. Keep the conversation honest. Let your healthcare. ...
  2. Share the issues and challenges you face with cravings and hunger.
  3. What are your weight and health goals?
  4. Discuss your overall health.
  5. Use your personal weight loss assessment to guide your conversation.

Are weight loss gummies safe? ›

Weight loss gummies use natural ingredients, so there are little to no harmful side effects on the body. Weight loss gummies are effective in losing unhealthy body weight and shedding kilos. It is time effective and also saves on a lot of energy.

What is the most effective weight loss pill? ›

Phentermine-Topiramate extended release (Qsymia) is the most effective weight loss drug available to date. It combines an adrenergic agonist with a neurostabilizer. Daily doses with four strengths start at 3.75/23mg to 15mg/92mg. Adults with migraines and obesity are good candidates for this weight loss medication.

What is the number one prescription for weight loss? ›

1. Lomaira, Adipex (phentermine) Phentermine is the most commonly prescribed weight-loss medication used in this country. It helps suppress appetite and make you feel fuller for longer.

What are the 4 FDA approved weight-loss drugs? ›

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.

Which is a common side effect of weight loss medication? ›

Common Side Effects of Weight Loss Drugs. Increased blood pressure and heart rate, insomnia, nervousness, restlessness, dependence, abuse or withdrawal may occur with long-term use. When given as a single agent, phentermine is not implicated in valvular heart disease; avoid use at bedtime.

What is the new FDA approved weight loss drug 2022? ›

Wegovy is now the first once-weekly weight loss drug approved for adolescents. A significant milestone to bring in the new year, the FDA approved Wegovy (semaglutide) on Dec. 23, 2022, for teens ages 12 and up who have a BMI at or above the 95th percentile for their age and sex.

What is the new miracle weight loss drug? ›

In June 2021, the FDA approved semaglutide (Wegovy), a once-weekly injection, for chronic weight management in adults when used in combination with a healthy diet and exercise. The medication had made headlines before its approval when the manufacturer reported 15% to 18% weight loss findings during clinical trials.

What is the downside of rapid weight loss? ›

Losing weight too fast may increase your risk of side effects including muscle loss, lower metabolism, nutrient deficiencies, gallstones and many other risks. This is especially true if you try to lose weight quickly without support from a health professional.

What does losing 20 pounds do for you? ›

"Losing 20 pounds, even if it's as little as 5-10% of your body weight, can reduce obesity-related risks," says D'Angelo, "and not only that, but losing 20 pounds can also help your overall quality of life, increase your mood, improve your lung function, and reduce blood sugar levels."

What are the dangers of rapid weight loss? ›

Possible serious risks include: Gallstones, which occur in 12% to 25% of people losing large amounts of weight over several months.
Other side effects of rapid weight loss include:
  • Headaches.
  • Irritability.
  • Fatigue.
  • Dizziness.
  • Constipation.
  • Menstrual irregularities.
  • Hair loss.
  • Muscle loss.
Aug 19, 2021

Can my primary doctor prescribe me weight loss pills? ›

Your primary care physician is not likely to give you a prescription for diet drugs immediately. Unhealthy body weight often comes with serious health conditions that must be factored into any weight loss plan.

How overweight do you have to be to be prescribed phentermine? ›

Phentermine side effects: Who is phentermine typically prescribed to? Phentermine is one of several medications that are FDA-approved to help treat obesity. Usually, phentermine can be prescribed if your body mass index (BMI) is higher than 30 kg/m2 or higher than 27 kg/m2 with other health conditions.

Who is a good candidate for phentermine? ›

Ideal candidates for medical weight loss with Phentermine should be:
  • In good general health.
  • Nonsmokers.
  • Have a BMI >30 or BMI >27 with secondary factors, such as hypertension or diabetes.
  • Be committed to following the program's guidelines closely.
  • Have realistic expectations for their results.
Mar 23, 2021

What happens to your body when you take fat burners? ›

Fat burners work more like an enhancer, giving you an extra boost of energy, speeding up your metabolism, whilst also encouraging the body to utilise fat stores as energy during an intense workout.

Is it healthy to take fat burners everyday? ›

Fat burners were not designed to be taken forever. They're designed as a supplement—to help you out during those times where your body might need a little boost. These products are supposed to help you reach a goal, not be used as a crutch all day, every day.

Are fat Burners effective for weight loss? ›

Fat burners can help enhance fat loss, but they're only supporting when you have a proper diet is in place. Fat burners work in a variety of ways, they boost energy, help curb appetite, promote fat to be used for energy, and increase your metabolism and core temperature so you burn more calories throughout the day.

What are the cons of taking phentermine? ›


Restlessness, insomnia, headache, psychosis, dry mouth, rash, sexual dysfunction, an unpleasant taste, and gastrointestinal disturbances may also occur. Treatment of more than a few weeks increases the risk of addiction and dependence on phentermine.


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