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FDA-Approved Weight Loss Drugs: Can They Help You?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on March 25, 2024.

Type 2 diabetes and weight loss medicines like Zepbound, Mounjaro, Wegovy and Ozempic have taken the U.S. by storm. Dramatic stories of weight loss, photos of thin celebrities and promises of a better life make everyone wonder if they can do it too.

But in the U.S., these newer drugs are often not covered by insurance due to high cost and lack of available generics. What are the options for weight loss?

While medicines can help with weight loss, diet and exercise can also ultimately lead to a healthy lifestyle and sustainable weight loss. Here, we'll review some of the older and newer weight loss treatments and look at their advantages and drawbacks.

Why should I lose weight?

According to the U.S. Centers for Disease Control and Prevention (CDC), there has been a dramatic increase in obesity in the last 20 years. More than 41% of U.S. adults and close to 20% of children under 18 years of age are obese, based on 2023 data.

These numbers are especially astounding because obesity and obesity-related conditions account for some of the leading causes of preventable deaths in the U.S. Obesity-related conditions include:

In addition, being overweight or obese is a recognized risk factor for many other major health problems including osteoarthritis, sleep apnea and breathing problems, mental health issues like depression, and gallbladder disease.

Be sure to talk to your doctor for sound advice before starting any weight loss program, learn about drug side effects, and understand it can take time and discipline for sustained weight loss.

What is a BMI?

Most weight-loss medications are prescribed based on your body mass index (BMI). It's important to understand how this is calculated so you can discuss it with your provider.

* BMI is a calculation of your weight in relation to your height that defines your health risk. BMI is calculated by dividing weight (in kg) by height (in meters) squared.
* Obesity is defined as a BMI over 30 kilograms/meter squared (kg/m2). 
* A BMI of 25 to 30 is considered overweight. A BMI of 18.5 to 24.9 is considered healthy.

In general, you should not use weight loss medications unless you are obese or at risk for a health-related condition, such as type 2 diabetes or high blood pressure. A healthy diet and regular exercise are part of the weight-loss regimen that should be continued even if weight loss medicines are stopped.

Zepbound vs. Wegovy

Weight loss agents are now available on the U.S. market that can help patients lose 20% or more of their weight when combined with diet and exercise. 

Zepbound, a GIP and GLP-1 receptor agonist from Eli Lilly, is used in combination with diet and increased physical activity, for:

Zepbound is a once-weekly injection given subcutaneously (under the skin) with a pre-filled single-dose pen. It contains tirzepatide, the same active ingredient that is in Lilly's Mounjaro, approved for type 2 diabetes.

At the highest 15 mg dose, people using Zepbound (tirzepatide) lost an average of 21.8 kg (48 lb) or 21% of their body weight, while at the lowest dose (5 mg), people lost an average of 15.5 kg (34 lb) or 15% of their body weight, compared to 3.2 kg (7 lb), or 3% in those using a placebo. The percent of patients using Zepbound that lost 5% or more of their body weight ranged from 85% to 91%, based on dose.

Wegovy, a GLP-1 receptor agonist injection from Novo Nordisk, is approved by the FDA for long-term weight management (in addition to diet and exercise) in:

In March 2024, Wegovy was also approved to reduce the risk of major adverse cardiovascular events (like heart-related death, heart attack, or a stroke) in adults with established heart disease and either obesity or overweight.

Wegovy contains semaglutide, the same active ingredient found in Novo's Ozempic approved for type 2 diabetes.

Wegovy is given as a subcutaneous injection under the skin once a week. It is injected on the same day each week, at any time of day, with or without meals. It comes in a self-administered pre-filled, single-dose pen for injection. You can learn to give this injection at home. 

In clinical studies, patients taking Wegovy (semaglutide) achieved an average weight loss of 14.9% of body weight at 68-weeks vs. 2.4% for placebo. In addition, 83.5% of patients achieved 5% or more body weight reduction in the Wegovy group compared to 31.1% for those taking a placebo (an inactive treatment).

Weight loss with Wegovy may begin within the first few weeks of treatment, but the full effects of treatment may not be seen for at least several months.

Ozempic and Rybelsus

Other prescription drugs, like Ozempic (also a subcutaneous injection) or Rybelsus (available as oral tablets), also contain semaglutide and can lead to weight loss, but are only approved to treat type 2 diabetes, together with diet and exercise, at this time.

Ozempic and Rybelsus might be prescribed "off-label" by some doctors for weight loss in people who do not have type 2 diabetes, but your insurance may not cover it for this use. Off-label means your doctor may prescribe a drug for a use not specifically approved by the FDA or listed in the package insert.

It's best to check with your insurance company for payment for any weight loss treatment, as they are often not covered.

RelatedHow do Ozempic, Mounjaro, Wegovy & Zepbound compare for weight loss?

Are there any alternatives to Wegovy and Zepbound?

Yes, there are several other weight loss products are approved by the FDA.

Saxenda (liraglutide) is also a glucagon-like peptide-1 (GLP-1) receptor agonist injection and is approved for chronic weight management in adults and children 12 years of age and older.

In a Saxenda study with over 3,700 patients, roughly 33% of people using Saxenda had a weight loss of 10% or more, losing about 23 lb (10.5 kg) from when they started the study. Approximately 6% of patients lost an average 47 lb (21.3 kg).

For adults, Saxenda is used in:

For children 12 years of age and older, Saxenda is used in:

For eligible patients, Saxenda is given as a subcutaneous (under the skin) injection once a day (in the abdomen, thigh, or upper arm). It comes as a prefilled injection pen and you can learn to self-inject this medicine so you can administer it at home.

Follow your doctors exact dosing instructions to reduce the likelihood of stomach side effects like nausea. 

If you have not lost 4% of your body weight after 16 weeks, your doctor may tell you to stop taking it. In children 12 years of age and older, your doctor may stop Saxenda after 12 weeks on the maintenance dose if BMI has not decreased by at least 1 percent.

Liraglutide (brand name: Victoza) is also approved for use in type 2 diabetes and to help reduce the risk of serious heart problems, but the two drugs should not be used together or with any other GLP-1 or GIP / GLP-1 receptor agonists like Wegovy, Ozempic or Zepbound.

Learn more: Saxenda side effects and warnings (in more detail)

How much weight can I lose with Qsymia?

In 2012, Qsymia (phentermine and extended-release topiramate) and Belviq (lorcaserin), two oral prescription medicines, were the first weight loss drugs approved in over a decade. However, Belviq was withdrawn from the market in 2020 due to safety concerns over a risk of cancer.

Qsymia is used for weight control in:

Qsymia is an oral capsule taken once daily by mouth. In one year clinical trials, Qsymia weight loss in adults averaged 11.2 lbs to 24 lbs (5.1 kg to 10.9 kg). After 1 year of treatment with Qsymia, all dose levels resulted in statistically significant weight loss compared to placebo (a pill with no active medicine).

However, there was a high drop out rate of patients in the studies, ranging from 31% to 40% at one year. Patients may have dropped out due to side effects or lack of effect.

How does Qsymia work?

Qsymia is a combination of two drugs, phentermine and extended-released topiramate. Phentermine acts to suppress the appetite, and topiramate (normally used as an anti-seizure medicine), is used because it may help people feel full.

Qsymia is taken once daily in morning with or without food; patients should avoid an evening dose as it may keep them awake. Your doctor will slowly increase your dose over a 28-day period and will evaluate your weight loss after 12 to 24 weeks of treatment, depending upon your final dose.

If you have not lost at least 5% of your weight or BMI after 12 weeks, your doctor may decide to stop Qsymia treatment. Do not stop treatment on your own too quickly as it may cause seizures; always talk to your doctor first.

Qsymia is classified as CIV controlled substance due to the phentermine component, which is an amphetamine derivative.

Learn more: Qsymia side effects and warnings (in more detail)

Why was Belviq withdrawn from the market?

The FDA requested the withdrawal of Belviq and Belviq XR (lorcaserin) from the US market in 2020 due to a reported increased risk of cancer.

Based on studies involving 12,000 people tracked for more than five years, the data showed that 7.1% of those taking a "dummy" placebo developed cancer, but that number rose to 7.7% among those taking Belviq. Cancer types included pancreatic, colorectal and lung cancer.

How does Contrave work for weight loss?

Contrave (bupropion and naltrexone) is an oral weight loss medicine that can be taken by mouth. It is an oral, extended-release form of two previously approved drugs, bupropion and naltrexone.

Contrave is approved to be used in obese (BMI of: 30 kg/m2 or greater) adults; or overweight (27 kg/m2 or greater) adults with at least one weight-related condition such as high blood pressure, high cholesterol, or type 2 diabetes. It's used alongside diet and exercise. The effect of Contrave on heart-related disease or death is not known.

It comes as extended-release tablets (8 mg naltrexone with 90 mg bupropion). The dose is increased weekly for 4 weeks, until a total daily dosage of two Contrave tablets given twice a day (morning and evening) is reached. Do not take Contrave with a high fat meal because it will increase the blood levels of the drugs.

After 12 weeks, if you have not lost at least 5% of your body weight, your doctor may decide to discontinue treatment. Total daily doses greater than 32 mg/360 mg (2 tablets twice a day) are not recommended. 

Learn more: Contrave side effects and warnings (in more detail)

Is alli the same as Xenical?

alli (orlistat) is the over-the-counter (OTC) version of the FDA-approved prescription drug Xenical 120 mg but it comes in a lower 60 milligram (mg) strength. It's used in adults in conjunction with diet and regular exercise to promote weight loss.

alli decreases the absorption of dietary fat by about 25% and therefore reduces the number of calories absorbed.

Clinical trials have only shown it to be only modestly effective; in general, a weight loss of 3 to 5 lbs (1.4 to 2.3 kg) per year would be expected over and above what you might lose from dieting and exercise alone.

How is alli taken?

alli is taken as one 60 mg capsule three times a day with each meal containing fat. Do not take more than 3 capsules per day.  Use alli in combination with diet and exercise. Do not use this medicine if you are pregnant or breastfeeding.

You should expect to lose most of your weight in the first 6 months.

It is also recommended to take a daily multivitamin at bedtime to help offset the loss of any fat-soluble vitamins. The vitamin should contain the fat soluble vitamins like A, D, E, K & beta carotene. Those with diabetes, thyroid disease or taking a blood thinner should consult with their doctor before using alli.

Side effects with alli may often hinder its use. and include loose stools, oily spotting, gas, bowel incontinence, and rarely liver injury (jaundice). Contact your doctor right away if you have symptoms of liver disease, such as yellow skin or eyes, itching, brown urine or stomach pain.

Learn more: alli side effects and warnings (in more detail)

Which weight loss medicine is best?

Unfortunately, there is no hard and fast answer to this question. Your doctor will individualize your weight loss treatment based on your medical history and conditions, previous treatments and cost concerns.

Comparative study

A study published in the Journal of the American Medical Association (JAMA) looked at some older weight loss treatments. Wegovy or Ozempic were not included in this research, but Saxenda, another GLP-1 agonist was.

In this study, researchers analyzed findings from 28 clinical trials with over 29,000 participants. Five approved drugs for obesity were evaluated: Qsymia, Saxenda and Xenical, along with Belviq (now discontinued from the US market) and Contrave.

All agents were associated with significant 5% weight loss compared with a placebo (an inactive medicine) after one year. Qsymia and Saxenda were associated with the highest odds of achieving at least 5% weight loss. However, in some cases a significant number of people dropped out because of side effects.


Qsymia (phentermine and topiramate XR): Typically, people lost the most weight with Qsymia, roughly 19 lbs (8.6 kg) more than those taking a placebo. Study patients were 9 times more likely to drop at least 5% of their initial weight.

Xenical or Belviq (now discontinued): People in these groups tended to lose 6 to 7 lbs (2.7 to 3.2 kg) more than placebo users over one year, the least amount of weight loss of all drugs studied. Belviq is no longer available in the US due to a possible cancer risk.

Contrave and Saxenda: Patients typically lost 11 to 12 lbs (5 to 5.5 kg) more in this group, compared with placebo, over one year. But, compared to placebo, Saxenda and Contrave were linked with the highest odds of stopping treatment due to side effects.

Stimulant Weight Loss Drugs

Drugs that are considered stimulant weight loss drugs include:

These stimulants are controlled substances approved for **short-term use** in weight loss, usually only up to 12 weeks maximum. As with other weight loss treatments, these drugs should be used in conjunction with ongoing diet and exercise to maintain weight loss.

Drugs that are stimulants (amphetamine-like) can lead to abuse and dependence with long-term use. Many doctors are reluctant to prescribe stimulants due to these risks and because of the availability of newer and safer weight loss options.

Often, the weight that is lost with stimulants will be regained when the medication is stopped. In contrast, alli, Contrave, Saxenda, Qsymia and Wegovy are all approved for long-term (chronic) use to help maintain your weight loss over the long-term.

Are OTC herbal weight loss pills safe and effective?

It is tempting to buy OTC weight loss pills -- they seem quick, easy and may claim to be "natural". However, dietary or herbal supplements are not reviewed by the FDA like prescription medicines. They may contain unknown chemicals that can be dangerous or counterfeit. Be especially careful buying these products online and only buy from a reputable website.

Chromium, Green Tea extract, Hoodia, and Guar Gum are just a few of the herbal dietary supplements available on the market today.

The FDA does investigate OTC supplements if they appear to be causing harm. In fact, the FDA removed dietary products with the stimulant ephedra from the U.S. market in 2004 due to dangerous side effects such as heart attack, stroke and seizures.

Do not combined prescription weight loss medicines with OTC weight loss products, or herbal or dietary supplements without speaking to your healthcare provider first.

Your individual weight-loss results may vary. If you questions about weight loss with these medications, contact your healthcare provider. 



Further information

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