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5 FDA-approved weight loss pills and medications for long-term treatment

Mike Bohl, MD, MPH, ALMchimene richa

Reviewed by Mike Bohl, MD, MPH, ALM, written by Chimene Richa, MD

Last updated: Feb 17, 2023
9 min read

Contrary to what popular culture might teach you, you cannot identify obesity in yourself or others simply by observation–obesity is a chronic medical condition that affects millions of people worldwide. And while BMI is not the be-all and end-all assessment of obesity (it’s not without its problems), more than 73% of adults over the age of 20 have measurements in the overweight or obese range in the United States—that’s more than two out of every three adults. For some people, diet and exercise are not enough. Continue reading to learn more about FDA-approved weight loss pills and medications that can help you lose weight and keep it off in a safe way. 


weight loss

Lose 15% of your body weight in one year on average


weight loss

Lose 15% of your body weight in one year on average

What are weight loss pills?

There are many different types of weight loss pills, also referred to as weight loss medications or anti-obesity medications. These pills work in different ways, including:

  • Suppressing your appetite (decreasing your desire to eat) 
  • Reducing how much fat you absorb from the foods you eat
  • Making you feel full faster

Weight loss medication is not for everyone–people who are pregnant, trying to become pregnant, or breastfeeding should not use weight loss medication (but more on who is eligible for weight loss pills later). 

Who is eligible for weight loss pills? 

Weight management medications are meant for adults over 18 years old with the following:

Wegovy (see Important Safety Information), a prescription weight loss medication, is available to children over 12 years old with either: 

  • Obesity: body mass index (BMI) of 30 kg/m2 or greater 
  • Overweight: BMI of 27 kg/m2 or greater with at least one weight-related medical condition, such as type 2 diabetes, high blood pressure (hypertension), or high cholesterol

The easiest way to determine your weight category is to measure your Body Mass Index (BMI). BMI is a measurement of your body weight in kilograms (1 kilogram equals 2.2 pounds) divided by your height in meters squared (1 meter equals ~3 feet 3 inches). You can easily calculate your BMI by clicking here. Using your BMI, you can determine which of the following categories applies to you:

If your BMI is higher than 25, you have an increased risk of several health conditions, including heart disease, stroke, diabetes, and severe COVID-19. Losing as little as 5–10% of the excess weight can significantly improve your health. Weight loss medications, in addition to diet, exercise, and lifestyle modifications, are appropriate for some people to help with their weight loss goals

It’s important to keep in mind that BMI does not account for factors like sex, body composition, and more. Additionally, research to support BMI as an assessment tool lacks racial and ethnic diversity.

How well do weight loss medications work?

Unfortunately, there is no magic pill to cure obesity. However, GLP-1 agonists, a class of drugs used to treat diabetes and manage weight, are proven to be highly effective weight management medications. GLP-1 agonists include:

GLP-1 drugs work by mimicking the hormone GLP-1, which sends signals to your brain letting it know when you are full, therefore decreasing your appetite and helping you to feel full faster. These weight loss pills also slow down the process of gastric emptying, when food inside the stomach moves into the small intestine during digestion.

In clinical trials, Wegovy (active ingredient semaglutide) was shown to help adults with a BMI higher than 30 decrease their body weight by up to 15%. While weight loss results will vary based on the type of GLP-1 drug prescribed, dosage, and other lifestyle and health factors, they have been proven to be very effective at helping people lose weight and maintain weight loss.

How long do I need to take weight loss medication?

How long you need to continue to take your weight loss medication depends on a number of factors and will vary from person to person. Depending on the side effects you experience and the success of your weight loss, your healthcare provider may need to adjust your dosage. Unfortunately, this means you might experience a trial and error period before seeing results. 

If your weight loss is successful and you don’t experience negative side effects, your healthcare provider may recommend continuing to take your weight loss medication long term to help you keep the weight off. If you take your medication as prescribed and aren’t seeing results, your healthcare provider may prescribe you a different weight loss pill.

That said, the Food and Drug Administration (FDA) has approved certain weight loss medications for short-term and long-term use. Continue reading to learn more.

Short-term weight loss pills

The FDA has approved four medications for short-term use (up to 12 weeks) to help achieve weight loss: 

These drugs are all stimulants that work by making you feel full faster so that you eat less. Some of these medications are Schedule IV, meaning that they have a higher potential for drug abuse. Potential side effects of these short-term weight loss pills include increased heart rate, high blood pressure, trouble sleeping (insomnia), dry mouth, constipation, and nervousness.

People with heart disease, poorly controlled high blood pressure, or a history of addiction or drug abuse should not use these medications. Never take weight loss pills if you are pregnant or breastfeeding. 

Long-term weight loss pills and medications

Given all of the risks of the short-term weight-loss drugs, most healthcare providers turn to treatments approved for longer time frames. There are currently five medications approved by the FDA for the long-term treatment of weight loss:

  • Phentermine/topiramate (Qsymia)
  • Liraglutide (Saxenda)
  • Semaglutide (Wegovy)
  • Naltrexone/bupropion (Contrave)
  • Orlistat (Xenical, Alli) 

These five drugs are all considered effective at helping people achieve at least 5% weight loss after using them for one year.  

Lorcaserin (brand name Belviq), a previously approved weight loss drug, has recently been withdrawn from the U.S. market. The FDA asked the manufacturing company, Eisai Inc., to voluntarily recall lorcaserin because of an increased cancer occurrence.

Continue reading to learn more about specific weight loss pills. 

Semaglutide (brand name Wegovy)

Semaglutide is a GLP-1 agonist and injectable drug used to treat diabetes. While there is an oral pill, only the injectable form is FDA-approved to treat obesity. As mentioned, semaglutide is extremely effective for weight management. Clinical trials showed that Wegovy was able to help adults with a BMI higher than 30 decrease their body weight by up to 15%. This drug also helped improve blood pressure and cholesterol measurements.

Common side effects include mild to moderate nausea, vomiting, diarrhea, and constipation, which are usually temporary. As with any medication used to treat diabetes, low blood sugar is a potential side effect.

Ro’s Body Program will connect you to a US-licensed healthcare professional who can discuss whether using a medication like Wegovy to lose weight is right for you. 

Phentermine/topiramate (brand name Qsymia)

Phentermine/topiramate is a combination of phentermine and the anti-seizure drug topiramate; using both drugs together works better than either drug alone to reduce appetite. Because of the potential for abuse, it is considered a scheduled drug by the DEA. You should avoid using phentermine/topiramate if you have high blood pressure or coronary heart disease. Side effects include dry mouth, constipation, paraesthesias (numbness/tingling), depression, anxiety, and elevated heart rate.

Liraglutide (brand name Saxenda)

Liraglutide, like semaglutide, is an injectable drug that is a member of the GLP-1 agonist drug class, most commonly used to treat type 2 diabetes. Studies have shown that it can also help you lose weight. Liraglutide affects how fast your stomach empties and the hormonal changes that occur after you eat a meal. The end result? You feel less hungry and eat less. Another benefit is that people with diabetes and cardiovascular disease have fewer heart attacks and strokes when taking liraglutide compared to placebo.  

Common side effects include nausea, vomiting, diarrhea, and low blood sugar. In rare cases, it can increase your risk of pancreatitis. Lastly, animal studies have shown that it may increase the risk of thyroid tumors—so far, clinical trials have not demonstrated an increase in thyroid tumors. However, people with a history of pancreatitis or thyroid tumors should avoid this medication.

Naltrexone/bupropion (brand name Contrave)

Naltrexone treats drug and alcohol dependence, while bupropion (see Important Safety Information) can improve depression and help people quit smoking. The combination of these two medications may affect dopamine, a brain chemical. By doing so, this drug reduces food cravings and decreases your appetite.

Common side effects of naltrexone/bupropion include nausea, headaches, constipation, insomnia, vomiting, dizziness, and dry mouth. Some people also notice elevations in blood pressure and heart rate while using naltrexone/bupropion. Since this combo medication includes bupropion, an antidepressant, it may increase the risk of suicide in young adults with depression when they first start treatment (a known side effect of antidepressants). 

People with uncontrolled high blood pressure, seizure disorders, eating disorders, chronic opioid use, severe liver failure should avoid using this drug. Also, anyone who has used monoamine oxidase inhibitors (MAOIs) in the past 14 days should not take naltrexone/bupropion because of the risk of serious side effects and drug interactions

Orlistat (brand names Xenical, Alli)

Orlistat works by decreasing the absorption of fats from your food—it reduces fat absorption by up to 30%. Orlistat is available in prescription strength (brand name Xenical) and a lower strength over-the-counter formulation (brand name Alli). 

Most of the side effects of orlistat affect your gastrointestinal (GI) system, including stomach rumbling, abdominal cramps, bloating, and constipation. Some of the more distressing GI effects include:

  • Passing gas (sometimes with oily spotting)
  • Diarrhea, loose stools, or greasy stools
  • Frequent bowel movements that are hard to control
  • Liver damage (rare effect)

Fortunately, most of these issues improve after using it for a while. Also, you can avoid some of them by sticking to a low-fat diet. Other side effects include poor absorption of fat-soluble vitamins (vitamins A, D, E, and K) and kidney stones.

Do weight loss pills replace diet and exercise? 

As much as we may wish, weight loss pills don’t replace diet and exercise. Treating obesity with weight loss drugs should only be used as part of a comprehensive treatment plan that includes lifestyle modifications, like diet and exercise, counseling, and behavioral interventions. Adding lifestyle changes may help you minimize weight regain once you stop the weight loss pills.

People taking weight loss medications along with lifestyle modifications lose, on average, 7–10% of their initial weight after one year. These compounding effects may improve your risk of multiple health problems like type 2 diabetes and high blood pressure. 

Weight loss medications may be the added boost you need to help you lose weight. However, they’re not for everyone. Talk to your healthcare provider about prescription medications for weight management to determine if medication is right for you. 


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.


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Dr. Mike is a licensed physician and the Director, Medical Content & Education at Ro.