Prescription Weight Loss Drugs: GLP-1s, Tirzepatide, and More

Prescription Weight Loss Medications

Keeping your weight in check sometimes can be a lifelong challenge. Following a healthy diet and staying physically active can help. So can prescription drugs.

Weight loss drugs may be an option for you if have obesity, which is defined as a body mass index (BMI) of 30 or higher. For an adult who is 5 foot 8 inches tall, that's a weight of 197 pounds or more.

Your doctor also may prescribe the drugs if your BMI is at least 27 and you have one or more weight-related health conditions, such as diabetes or high blood pressure.

They're intended to be used along with a reduced-calorie eating plan and exercise program. Many people lose a significant amount of weight with the medications. Others lose less or very little. 

Some insurance plans cover weight loss medications, but most do not. They're more likely to be covered if you need the drugs for an added purpose, like reducing your heart disease risk. Medicare Part D may cover weight loss drugs if they're prescribed to treat another health condition like diabetes.

Before you get a weight loss drug prescription, tell your doctor about your medical history. That includes any allergies or other conditions you have; medicines or supplements you take (even if they're herbal or natural); and whether you're pregnant, breastfeeding, or planning to get pregnant soon.

GLP-1s

One class of drugs called glucagon-like peptide-1 (GLP-1) agonists is used to treat both obesity and type 2 diabetes.

GLP-1 is a hormone that's found in your digestive system. It's released when you eat and tells your body to make insulin to control your blood sugar. It also slows down how quickly your food moves from your stomach to your intestines, and it gives your brain the signal that you feel full. 

If you don't have enough of this hormone, or if it doesn't work the way it should in your body, a GLP-1 agonist can give your system a boost.

Beyond helping you lose weight and keep your blood sugar under control, these drugs have also been shown to improve your blood pressure and cholesterol numbers and lower your heart disease risk.  

Because GLP-1 agonists lower your blood sugar, you shouldn't take them at the same time as you take insulin or certain other diabetes medications or your blood sugar could drop dangerously low.

Semaglutide (Wegovy)

How does Wegovy work? 

Semaglutide is a GLP-1 agonist. It imitates an intestinal hormone that stimulates insulin production, lowering your appetite and making you feel full.

In the largest clinical trial that tested Wegovy before its FDA approval, people taking the highest dose (2.4 milligrams) lost, on average, more than 12% of their body weight over 17 months. 

How to take Wegovy

Wegovy is a shot you give yourself once a week with a prefilled pen in the skin of your abdomen, thigh, or upper arm. You start with a low dose, 0.25 milligrams, and increase it gradually over several months to the amount your doctor has prescribed, either 1.7 or 2.4 milligrams.

Approved for long-term use (more than 12 weeks)? 

Wegovy side effects 

Most side effects are mild and temporary. They include:

• Nausea
• Diarrhea 
• Abdominal cramping 
• Constipation 
• Vomiting 
• Gas 
• Headache 
• Fatigue
• Heartburn 

Less common but more serious possible side effects include an allergic reaction; problems with your gallbladder, kidneys, or pancreas; blurred vision; increased heart rate; and suicidal thoughts. 

Semaglutide has been shown in studies to cause a rare kind of thyroid tumor in animals, but it is not known if it can cause thyroid cancer in people.

Wegovy costs

The company that makes Wegovy, Novo Nordisk, says the list price is $1,349 for a 4-week supply. Novo Nordisk also has a savings program to help with your out-of-pocket costs.

You might need to take semaglutide for life to manage your weight. Quitting it can lead to regaining most of the lost weight.

There are no approved generic versions of Wegovy, despite what you may see advertised. The FDA warns that versions of semaglutide you might be able to get from a compounding pharmacy or other facility may be a different formula from the branded version and may not be effective or safe.

Semaglutide (Ozempic)

How does Ozempic work? 

Semaglutide is a GLP-1 agonist. It imitates an intestinal hormone that stimulates insulin production, lowering your appetite and making you feel full.

Ozempic isn't approved for weight management, although many people taking it do lose weight. It's sometimes prescribed off-label for that purpose. 

How to take Ozempic

Ozempic is an injection you give yourself once a week with a prefilled pen in the skin of your abdomen, thigh, or upper arm. You start with a 0.25 milligram dose for the first month then increase that to 0.50 milligrams. Some people may be prescribed 1 or 2 milligrams.

Approved for long-term use? 

Yes.

Ozempic side effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal cramping 
• Constipation 

Less common but more serious side effects include an allergic reaction, problems with your pancreas, kidneys, or gallbladder, and vision changes.  

Semaglutide has been shown in studies to cause a rare kind of thyroid tumor in animals, but it is not known if it can cause thyroid cancer in people.

Ozempic costs

The company that makes Ozempic, Novo Nordisk, says the list price is about $936 for a 4-week supply. Novo Nordisk has a savings program that may help with your out-of-pocket costs.

What else you should know

You've probably heard the term "Ozempic face" to describe the changed appearance of people who've lost significant amounts of weight. When you lose a lot of weight in a relatively short period of time, you can end up with loose skin, which translates into wrinkles. Fat loss in your face can change the shape of your features and make your eyes and cheeks appear sunken. But that's not a side effect of Ozempic -- any quick weight loss can cause those changes.

Wegovy vs. Ozempic 

Ozempic is the same medication as Wegovy: semaglutide. Under the brand name Ozmepic, it's approved to treat type 2 diabetes, while under the brand name Wegovy, it's approved for weight loss. Wegovy is typically prescribed in a higher dose than Ozempic.

Another difference is in how you'll pay for it. Insurance generally covers Ozempic for diabetes control. It's less common for Wegovy to be covered. 

How does Saxenda work?  

Liraglutide is GLP-1 agonist. It mimics an intestinal hormone that tells your brain your stomach is full.

How to take Saxenda

Saxenda is an injection you give yourself once a day in the skin of your abdomen, thigh, or upper arm using a prefilled pen. You start with 0.6 milligrams for the first week and gradually increase the dose over a month until you reach 3 milligrams a day. 

Approved for long-term use? 

Yes.

Saxenda side effects 

Common side effects include:

• Abdominal pain
• Nausea
• Vomiting
• Diarrhea 
• Constipation 

Serious potential side effects can include an allergic reaction, raised heart rate, pancreatitis, gallbladder disease, kidney problems, and suicidal thoughts. 

Liraglutide has been shown in studies to cause thyroid tumors in animals, but it is not yet known if it can cause thyroid cancer in people.

Saxenda costs

According to the company that makes Saxenda, Novo Nordisk, the list price is $1,350 for a 1-month supply. 

What else you should know 

Liraglutide (Victoza)

How does Victoza work? 

Liraglutide is a GLP-1 agonist. It mimics an intestinal hormone that stimulates insulin production and tells your brain your stomach is full.

Victoza is approved to treat type 2 diabetes, not obesity. But people who take it have lost weight.

How to take Victoza

Victoza is an injection you give yourself once a day in the skin of your abdomen, thigh, or upper arm using a prefilled pen. You start with 0.6 milligrams for the first week, then increase to 1.2 milligrams. Some people may be prescribed 1.8 milligrams. 

Approved for long-term use? 

Yes.

Victoza side effects 

Common side effects of Victoza include:

• Nausea
• Vomiting
• Diarrhea 
• Constipation 
• Indigestion 

Serious potential side effects can include an allergic reaction, raised heart rate, pancreatitis, gallbladder disease, kidney problems, and suicidal thoughts. 

Liraglutide has been shown in studies to cause thyroid tumors in animals, but it's not yet known if it can cause thyroid cancer in people.

According to the company that makes Victoza, Novo Nordisk, the list price is between about $543 and $815 for a 1-month supply, depending on your dose. The company has a patient assistance program for people who qualify.

What else you should know 

Victoza and Saxenda are the same medication: liraglutide. Under the brand name Victoza, it's approved to treat type 2 diabetes, while under the brand name Saxenda, it's approved for weight loss. The doses are different also. The long-term dose of Saxenda is almost double the highest dose of Victoza. 

While insurance generally covers GLP-1 agonists for diabetes control, it's less common when they're prescribed for weight management.

Dulaglutide (Trulicity)

How does Trulicity work? 

Dulaglutide is another kind of GLP-1 agonist. It imitates an intestinal hormone that stimulates insulin production, lowering your appetite and making you feel full. 

It's only approved to treat type 2 diabetes, but people taking it do lose weight. 

How to take Trulicity

Trulicity is an injection you give yourself once a week under the skin of your abdomen, thigh, or upper arm using a prefilled pen. The dose starts at 0.75 milligrams for the first week, then increases to 1.5 milligrams. Some people may be prescribed up to 4.5 milligrams.

Approved for long-term use? 

Trulicity side effects 

Common side effects of Trulicity include:

• Nausea
• Diarrhea
• Vomiting
• Abdominal pain 
• Indigestion
• Fatigue

Less common but more serious side effects include an allergic reaction, pancreatitis, kidney damage, vision changes, and gallbladder problems.

Dulaglutide has been shown in studies to cause thyroid tumors in animals, but it's not yet known if it can cause thyroid cancer in people.

Trulicity costs

The company that makes Trulicity, Eli Lilly, says the list price is about $977 for a 4-week supply.

Exenetide (Byetta)

How does Byetta work? 

Exenetide is the oldest of the GLP-1 agonists approved to treat type 2 diabetes. It imitates an intestinal hormone that stimulates insulin production, lowering your appetite and making you feel full. 

It's not approved for weight management, but people who take it do lose weight.

Byetta is an injection you give yourself twice a day under the skin of your abdomen, thigh, or upper arm using a prefilled pen. Take it an hour or less before a meal, and make sure the doses are at least 6 hours apart.

Approved for long-term use? 

Yes.

Byetta side effects 

Common side effects of Byetta include:

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Indigestion
• Dizziness
• Headache

Less common but more serious side effects include an allergic reaction, pancreatitis, gallbladder problems, and kidney damage. 

Some people develop an immune system reaction to exenetide. Your immune system could produce antibodies that make the drug stop working. Another kind of immune reaction can lead to serious bleeding. 

Byetta costs

The retail price of Byetta varies by pharmacy, but is around $900 for a 1-month supply. AstraZeneca, the company that makes Byetta, has a program to help with your out-of-pocket costs. 

What else you should know 

Exenatide can interfere with oral birth control. Be sure you take your birth control pill at least an hour before giving yourself a Byetta injection. If you also take the blood thinner warfarin, you may have a higher risk of uncontrolled bleeding.  

How does Bydureon BCise work? 

Exenetide is the oldest of the GLP-1 agonists approved to treat type 2 diabetes. It imitates an intestinal hormone that stimulates insulin production, lowering your appetite and making you feel full.

It isn't approved for weight management, but people who take it do lose weight.

How to take Bydureon BCise

Bydureon BCise is an injection you give yourself once a week using a prefilled pen.

Approved for long-term use? 

Yes.

Bydureon BCise side effects 

Common side effects of Bydureon BCise include:

• A lump at the injection site
• Nausea
• Headache
• Diarrhea
• Vomiting
• Dizziness
• Constipation

Less common but more serious side effects include an allergic reaction, pancreatitis, gallbladder problems, and kidney damage. 

Some people can develop an immune system reaction to exenatide. Your immune system could produce antibodies that make the drug stop working. Another kind of immune reaction can lead to serious bleeding.

Bydureon BCise costs

The retail price of Bydureon BCise is between about $800 and $900, depending on your pharmacy. The company that makes Bydureon BCise, AstraZeneca, has a program to help with your out-of-pocket costs.

What else you should know 

Bydureon BCise is an extended-release form of the same medication in Byetta: exenatide.

Exenatide can interfere with oral birth control. Be sure you take your birth control pill at least an hour before giving yourself a Bydureon BCise injection. If you also take the blood thinner warfarin, you may have a higher risk of uncontrolled bleeding. 

GIP/GLP-1s

The newest class of drugs that treat both type 2 diabetes and obesity work with both of the main digestive hormones that tell your body to make insulin: GLP-1 and glucose-dependent insulinotropic polypeptide (GIP). 

Tirzepatide imitates both GLP-1 and GIP, increasing your body's production of insulin and lowering your blood glucose levels. It also slows down how quickly food moves from your stomach to your intestines and helps you feel full.

Research done as part of the drug's approval process for treating type 2 diabetes found people lost as much as 21 pounds over 10 months. A 17-month study specifically looking at its effect on obesity showed people on the highest dose of tirzepatide (15 milligrams) lost on average just over 20% of their body weight.

Benefits related to your heart health are still being studied. But so far, data shows taking tirzepatide may improve blood pressure and cholesterol numbers. 

Tirzepatide vs. semaglutide

The SURPASS-2 clinical trial compared tirzeparide to semaglutide head to head. It found people taking tirzepatide for type 2 diabetes lost as much as 12 pounds more than people taking a 1-milligram dose of semaglutide for 40 weeks.

When studies that measure how a 2-milligram dose of semaglutide affects weight loss in people with type 2 diabetes are analyzed, tirzepatide still comes out on top.

How does Zepbound work? 

Tirzepatide mimics two hormones, one that regulates insulin when your blood sugar rises and the other a gut hormone. Together, they dampen your appetite so that you eat less. 

How to take Zepbound

Zepbound is an injection you give yourself once a week in the skin of your stomach, upper arm, or thigh using a prefilled pen. The dosage goes up over several months until you reach your target dose, which can be 5, 10, or 15 milligrams.

Approved for long term-use? 

Yes. Not approved for children.

Zepbound side effects

Common side effects can include: 

• Nausea
• Diarrhea
• Vomiting
• Stomach pain
• Constipation (trouble pooping)

These usually go away after you get to the dose you've been prescribed and your body adjusts, but sometimes they can be serious.

Less common but more serious possible side effects include an allergic reaction, pancreatitis, gallbladder problems, vision changes, kidney damage, and suicidal thoughts.

Zepbound costs

The company that makes Zepbound, Eli Lilly, says the list price is about $1,060 for a 4-week supply. Eli Lilly has a program that can help with your out-of-pocket costs.

What else you should know 

You may have to stay on Zepbound for life for weight management. Quitting it can lead to regaining much of the weight you lost. 

Tirzepatide (Mounjaro)

How does Mounjaro work?

Mounjaro activates receptors for both the hormones GLP-1 and GIP and leads to improved blood sugar control. 

It isn't approved for treating obesity, but during tirzepatide diabetes trials, researchers noted people who got tirzepatide lost much more weight than those on standard diabetes therapy.

How you take Mounjaro

Mounjaro is an injection you give yourself once a week in the skin of your stomach, upper arm, or thigh, using a prefilled pen. You start with a 2.5-milligram dose and increase to 5 milligrams after a month. Some people may be prescribed up to 15 milligrams.

Yes. 

Mounjaro side effects 

Common side effects include:

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Abdominal pain

Less common but more serious side effects include an allergic reaction, pancreatitis, gallbladder problems, vision changes, and kidney damage.

Mounjaro costs

The company that makes Mounjaro, Eli Lilly, says the list price is about $1,070 for a 1-month supply. Eli Lilly has a program that can help with your out-of-pocket costs.

Zepbound vs. Mounjaro

Zepbound and Mounjaro are the same medication: tirzepatide. Under the brand name Zepbound, it's approved to treat obesity, while under the brand name Mounjaro, it's approved to treat type 2 diabetes.  

Your insurance may cover tirzepatide for diabetes control. It's less likely to be covered for weight management. 

Naltrexone HCl and bupropion (Contrave)

How does Contrave work? 

Contrave is a combination of two FDA-approved drugs, naltrexone and bupropion, in an extended-release formula. Naltrexone is approved to treat alcohol and opioid dependence. Bupropion is approved to treat depression and seasonal affective disorder and help people stop smoking.

Contrave appears to signal your brain to lower your appetite.

Contrave is a tablet that you take twice a day. You start out taking one pill a day and gradually increase the dose over a month until you're taking two pills twice a day. 

Approved for long-term use? 

Yes.

Contrave side effects 

The most common side effects include: 

• Nausea
• Constipation
• Diarrhea
• Headache
• Vomiting
• Dizziness
• Insomnia
• Dry mouth 

Rare but serious side effects include an allergic reaction, seizures, liver damage, increased blood pressure or heart rate, and vision problems.

Contrave has a boxed warning about the increased risk of suicidal thoughts and behaviors associated with bupropion. The warning also notes that serious neuropsychiatric issues linked to bupropion have been reported. 

Contrave costs

The retail price for Contrave ranges from about $700-$800 for a 1-month supply, depending on your pharmacy. The company that makes it, Currax, has a program to help with your out-of-pocket costs.

What else you should know

You shouldn't take Contrave with a high fat meal or if you drink a lot of alcohol. That increases the seizure risk. It also can't be mixed with pain relievers or other drugs that contain opioids. 

If you don't lose 5% of your weight after 12 weeks of taking Contrave, your doctor may tell you to stop taking it because it's unlikely to work for you, the FDA says.

How does Xenical work? 

Orlistat blocks your body from absorbing about a third of the fat you eat.

When a doctor prescribes it, it's called Xenical. If you get it without a prescription, it's called Alli, which has half of Xenical's dose.

How you take Xenical

Xenical is a pill you take three times a day, either with or within an hour of eating a meal that contains fat.

Approved for long-term use 

Yes.

Xenical side effects

Common side effects of Xenical include:

• Abdominal cramping
• Gas
• Leaking oily stool
• Having more bowel movements
• Not being able to control bowel movements

These side effects are generally mild and temporary. But they may get worse if you eat high-fat foods.

Rare cases of severe liver injury have been reported in people taking orlistat, but it's not certain that the drug caused those problems.

Xenical costs

Prescription Xenical costs around $800 for a 1-month supply. There are generic versions of orlistat that are cheaper. Over-the-counter Alli costs less than $60 for a month.

What else you should know 

You should be on a low-fat diet (less than 30% of your daily calories from fat) before taking orlistat.

Also, take a multivitamin at least 2 hours before or after taking orlistat because the drug temporarily makes it harder for your body to absorb vitamins A, D, E, and K.

Orlistat is the only drug of its kind that's approved in the U.S. All other prescription weight loss drugs curb your appetite.

Phentermine

How does phentermine work? 

Phentermine curbs your appetite.

Your doctor may prescribe this under the names Adipex-P or Lomaira. 

How you take phentermine

Phentermine comes as either a tablet, a capsule, an extended-release capsule, or a disintegrating tablet. The exact dosage and timing depend on what your doctor prescribes, but in most cases you take it once a day, either before or after breakfast.  

Approved for long-term use?

No. It's approved for short-term use (a few weeks) only.

Phentermine side effects

Side effects of phemetermine can be serious, such as: 

• Raised blood pressure 
• Heart palpitations 
• Restlessness
• Dizziness
• Tremor
• Insomnia
• Shortness of breath
• Chest pain
• Trouble doing activities you've been able to do

Less serious side effects include dry mouth, unpleasant taste, diarrhea, constipation, and vomiting.

Don't take it late in the evening, as it may cause insomnia.

If you take insulin for diabetes, let your doctor know before you take phentermine, as you may need to adjust your insulin dose.

You should not take phentermine if you have a history of heart disease, stroke, congestive heart failure, or uncontrolled high blood pressure. You also shouldn't take it if you have glaucoma, hyperthyroidism, or a history of drug abuse, or if you are pregnant or nursing.

Phentermine costs

The retail price is more than $70 for a month's supply, or between $30-$40 for generic versions, depending on which pharmacy you choose.

What else you should know

Phentermine is an amphetamine. Because of the risk of addiction or abuse, such stimulant drugs are "controlled substances," which means they need a special type of prescription. Other drugs similar to phentermine that may be an option include benzphetamine, diethylpropion, and phendimetrazine.

Phentermine and Topiramate (Qsymia)

How does Qsymia work? 

Qsymia combines phentermine with the seizure/migraine drug topiramate. Phentermine curbs your appetite, while topiramate causes weight loss in several ways, including helping you feel full, making foods taste less appealing, and burning more calories.

How you take Qsymia

Qsymia is a pill you take once a day in the morning.

Approved for long-term use? 

Yes. Qsymia has much lower amounts of phentermine and topiramate than when these drugs are given alone.

Qsymia side effects

Common side effects include: 

• Tingling hands and feet
• Dizziness
• Altered sense of taste
• Insomnia
• Constipation
• Dry mouth

Serious side effects include: 

• Certain birth defects (cleft lip and cleft palate)
• Faster heart rate
• Suicidal thoughts or actions
• Eye problems that could lead to permanent vision loss if not treated

Women who might become pregnant should get a pregnancy test before taking Qsymia and should use birth control and get monthly pregnancy tests while on the drug.

You also shouldn't take Qsymia if you have glaucoma, hyperthyroidism, heart disease, or stroke. Get regular checks of your heart when starting the drug or increasing the dose.

Qsymia costs

The retail price of Qsymia ranges from about $210 to $280 for a 1-month supply, depending on the dosage and which pharmacy you choose. The company that makes it, Vivus, has a program to help with your out-of-pocket costs.

What else you should know

If you don't lose at least 3% of your weight after 12 weeks on Qsymia, the FDA recommends that you stop taking it or that your doctor increase your dose for the next 12 weeks -- and if that doesn't work, you should gradually stop taking it.

Plenity

How does Plenity work? 

Plenity isn't a drug -- it's sold as a medical device. It's a substance called a hydrogel that's made up of cellulose and citric acid. It absorbs liquid and expands in your stomach. By taking up space, it makes you feel full so you eat less.

How you take Plenity

Plenity comes in capsules. You take three capsules twice a day 20 minutes before lunch and dinner along with 16 ounces of water.

Approved for long-term use? 

Yes.

Plenity side effects

Common side effects include: 

• Bloating
• Gas
• Abdominal pain

Plenity costs

The company that makes Plenity, Gelesis, sells a 4-week supply with a prescription for $98.

What else you should know

Plenity isn't considered a drug because it's never absorbed by your body. After it moves through your stomach and small intestines, it's broken down by your large intestine and comes out when you poop.

Weight Loss Drugs in Development

Doctors are studying new treatment strategies to help people lose weight and to stay at a healthy weight. Drugs are being developed to: 

• Boost different hunger-controlling hormones like glucagon
• Work on more than one hormone at once, like tirzepatide does
• Be available as a pill rather than an injection
• Help increase muscle mass while reducing fat

Prescription Weight Loss Drugs Benefits

Prescription medications can be very effective in helping you lose weight.

Over the course of a year, people who take prescription weight loss drugs in addition to following a program of exercise and healthy eating lose 3%-12% more of their starting weight than people who make lifestyle changes alone. That's according to the National Institute of Diabetes and Digestive and Kidney Diseases.

Different drugs have different results, but clinical trials have shown that many can help you lose 5%-10% of your body weight or more. That kind of weight loss can lead to other health improvements like lowered blood pressure, blood sugar, and some blood fats, and can improve joint pain and sleep apnea.

Prescription Weight Loss Drugs Risks

All of these drugs can have some amount of unpleasant side effects, usually digestive. But other potential side effects can be more serious. Depending on your overall health, some side effects may be more dangerous than the risks of being overweight.

Prescription weight loss drugs don't work for everyone. And if they do help you, you may have to take them indefinitely or risk regaining most of the weight you lost. 

Prescription Weight Loss Drugs Stigma

The newest generation of weight loss drugs is changing the conversation about obesity. As researchers learn more about the biological processes involved in appetite and metabolism, weight management shifts from a matter of willpower to a complex but medically treatable condition. 

Still, stigma and shaming about being overweight persist. You may hesitate to bring it up with your doctor or feel that it's somehow cheating to get help from prescription drugs. The high price and limited availability of some prescription weight loss drugs contributes to the perception that they're just for the rich and famous who want to stay red carpet-ready.

But doctors say obesity should be considered the same way as other chronic conditions that can be treated and kept under control through medication.

Clinical Trials for Weight Loss Drugs

Clinical trials are an important part of the process by which new drugs become available. Researchers test experimental medications to find out if they're safe and effective.

By taking part in one, you can help doctors learn more about ways to lose weight and keep it off, and you could get early access to the next breakthrough treatment.

One way to find a clinical trial is through clinicaltrials.gov. That's a government-run database listing thousands of ongoing studies. You can search by condition and location. 

Your doctor can help you decide whether a clinical trial is right for you and may know about one you can join.

Takeaways

Prescription weight loss drugs can be an effective treatment for obesity. However, they aren't often covered by insurance, and some are very expensive. You could lose 10% of your body weight or more with these drugs, but you may have to take them for life to keep the weight off.