Weight Loss
31 min read
Written by Emily Van Devender
Published: Feb 16, 2024
Medically Reviewed by Goldina Erowele, PharmD, MBA
If setbacks and barriers have interfered with your weight loss journey, it may be time to consider the extra boost that weight-loss medications offer. In this article, we cover some of the best prescription weight loss pills available today along with some potential future medications.
Getting the facts on weight loss medications and how they work is crucial for finding the right fit. Once you know the basics, talk to your healthcare provider about which one may be right for you.
Klarity lets you find a licensed healthcare provider to manage your weight loss with a tailored medically supervised weight loss program that may include medication.
Prescription weight loss medications can support healthy weight loss alongside a reduced-calorie diet and exercise program. There are several weight loss medications on the market, including oral tablets and weight loss injections. Always consult with your healthcare provider before starting any prescription or over-the-counter medication or supplement.
Following are today’s best prescription weight loss medications listed with the most effective first down to least effective for weight loss based on trials and studies.
Weight loss medication | Potential weight loss | Cost* | Drugs.com rating** |
Zepbound (tirzepatide) | 20.9% body weight or up to 63 lbs for a 300 lb person | $1,060 | 8.8/10 |
Wegovy (semaglutide) | 14.9% of initial body weight in 68 weeks or up to 45 lbs for a 300 lb person | $1,430 | 7.1/10 |
Saxenda (liraglutide) | 5–10% body weight or up to 30 lbs for a 300 lb person | $1,430 | 7.5/10 |
Qsymia (phentermine-topiramate) | 5–10% body weight in 56 weeks or up to 30 lbs for a 300 lb person | $211 | 7.7/10 |
Contrave (bupropion-naltrexone) | 5–10% body weight up to 30 lbs for 300 lb person | $668 | 6.6/10 |
Adipex-P (phentermine) | at least 3% weight loss in 3 mos or 9 lbs for a 300 lb person | $80 | 8.9/10 |
Plenity | 6.4% body weight in 6 mos or 19 lbs for a 300 lb person | $98 | 4/5 per aging.com |
Xenical (orlistat) | 2.4% body weight in 4 yrs or 7 lbs for a 300 lb person | $803 | 8.3/10 |
*Cost of a one-month supply before insurance per drugs.com as of the date of publication.
**Unless otherwise indicated
Newest to the market, Zepbound was approved by the Food and Drug Administration (FDA) in November 2023 for chronic weight management in adults in combination with a reduced-calorie meal plan and increased physical activity. To take Zepbound, people need to have a body mass index (BMI) over 30 or more or a BMI equal to or more than 27 with at least one weight-related health condition, for example, high blood pressure or type 2 diabetes. BMI measures body fat based on a calculation of body weight and height.
Zepbound is an injectable medication taken once a week.
How it works
Zepbound is a name-brand version of tirzepatide, which is a glucagon-like peptide-1/gastric inhibitory polypeptide (GLP-1/GIP) dual agonist. GLP-1 and GIP are natural hormones produced in the body that inhibit glucagon secretion and prompt the secretion of insulin to help control blood sugar levels and reduce appetite. GLP-1/GIP dual agonists support weight loss by binding to the body’s GLP-1 and GIP receptors to reduce appetite and calorie intake.
Note that in clinical trials, patients gained substantial weight when they stopped taking Zepbound.
Effectiveness
In clinical trials, people taking Zepbound lost up to 20.9% of their initial body weight. For a 300-pound person, 20.9% weight loss equals roughly 63 pounds.
Cost
Before insurance or manufacturer’s discounts, a 28-day supply of Zepbound costs $1,060 according to drugs.com. Currently, there’s no generic version of tirzepatide on the market. The identical drug is available under the brand name Mounjaro, which is approved for type 2 diabetes treatment, but not weight loss. It costs roughly $1,135 for a 28-day supply per drugs.com.
Common side effects
Zepbound can cause gastrointestinal side effects, such as stomach pain, nausea, vomiting, acid reflux, and diarrhea. Other possible side effects include skin reactions at the injection site and hair loss. For a complete list of side effects, see the Zepbound medication guide or talk to your healthcare provider or pharmacist.***
Rating
Zepbound has an average rating of 8.8/10 on drugs.com when used for weight loss purposes, making it a favorite option among consumers.
Wegovy is a name-brand injectable semaglutide. It was approved by the FDA in 2021 for weight loss when combined with a reduced-calorie meal plan and increased physical activity for adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition. It’s taken once a week. Before the approval of Zepbound, it was the first drug in its class to earn approval since 2014.
A similar medication called Ozempic is used to treat type 2 diabetes and is often prescribed off-label for weight loss. Wegovy and Ozempic have been so popular for weight loss, that both medications have experienced supply shortages. Before starting either, make sure to work with your healthcare provider or pharmacist to ensure you can find Wegovy or Ozempic in stock.
How it works
Wegovy is a GLP-1 agonist. It binds to GLP-1 receptors in your stomach to reduce your appetite. It also transports glucose (sugar) into the cells, where it’s used to produce energy.
You need to continue to commit to a healthy lifestyle after stopping Wegovy or you run the risk of regaining the weight.
Effectiveness
In clinical trials, participants lost an average of 14.9% of their initial body weight in 68 weeks while taking Wegovy, 12.4% more than participants on a placebo. For a 300-pound person, a 14.9% weight loss equals almost 45 pounds.
Cost
Before insurance coverage or manufacturer discounts, a 28-day supply of Wegovy costs $1,430. There’s currently no generic version of Wegovy.
Common side effects
While using Wegovy, you might have side effects, such as nausea, vomiting, diarrhea, or constipation, which often resolve in a few weeks. For a complete list of side effects, see the Wegovy medication guide or talk to your pharmacist or healthcare provider.***
Rating
When used for weight loss, Wegovy has a 7.1/10 consumer rating on drugs.com.
Saxenda is a weight loss medication that’s injected under the skin once a day. Approved by the FDA in 2014, Saxenda is used for weight management when combined with a reduced-calorie meal plan and increased physical activity for adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition.
How it works
Saxenda’s active ingredient, liraglutide, is a GLP-1 agonist. It binds to GLP-1 receptors to slow down digestion and control appetite. Saxenda and Victoza, which is approved for type 2 diabetes treatment, have the same active ingredient, liraglutide, and should not be used together or with other GLP-1 receptor agonist medicines.
Effectiveness
Saxenda clinical trial participants lost an average of 8% of their body weight after 56 weeks when combining daily liraglutide with diet and lifestyle changes. For a 300-pound person, 8% equals 24 pounds.
Cost
A 30-day supply of the maintenance dose of Saxenda (3 milligrams a day) costs $1,430 per drugs.com. There are currently no lower-cost FDA-approved generic versions of Saxenda.
Side effects
The most common side effects of Saxenda are nausea, vomiting, diarrhea, and constipation. Stopping Saxenda can lead to digestive symptoms like nausea and vomiting. Contact your healthcare provider before stopping or changing your medications. See the Saxenda medication guide for full details on side effects or talk to your healthcare provider or pharmacist.***
Rating
Saxenda has an average rating of 7.5/10 from consumers on drugs.com.
Qsymia is a prescription oral medication approved by the FDA in July 2012. It’s intended for weight management when combined with a reduced-calorie meal plan and increased physical activity for adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition.
How it works
Qsymia combines 2 different medications, phentermine and topiramate. Phentermine is an appetite suppressant that works in the brain. Topiramate is an anti-seizure medication that helps you feel fuller. It is best to take Qsymia in the morning to prevent insomnia
Effectiveness
In Qsymia clinical trials, participants lost between 5 and 10% of their body weight in 56 weeks.
Cost
Before insurance, manufacturer’s benefits, and other discounts, the average cost of Qsymia is $211 a month per drugs.com. There are currently no lower-cost FDA-approved generic versions of Qsymia.
Common side effects
Milder and more common side effects when taking Qsymia are dry mouth, pins-and-needles, and symptoms similar to an upper respiratory infection. If you stop taking Qsymia suddenly, you run the risk of withdrawal symptoms, including seizures. These are far less likely when you taper off the drug according to your provider’s instructions. See the Qsymia medication guide or talk to your healthcare provider or pharmacist.***
Dependency warning
Qsymia is a Schedule IV controlled substance and has a high risk for addiction, especially if misused. Don’t take it more often or in higher doses than prescribed by your healthcare provider, as this increases the risk of developing dependency.
Rating
Qsymia has an average rating of 7.7/10 among consumers on drugs.com.
Contrave is an oral medication taken daily as part of a weight management program. Approved by the FDA for weight loss purposes in 2014, Contrave is used for weight management in adults when combined with a reduced-calorie meal plan and increased physical activity for adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition.
How it works
Contrave is a combination of two drugs: bupropion, an antidepressant, and naltrexone, an opioid antagonist. Together, they work to help control your appetite and cravings by affecting your brain’s reward system.
Effectiveness
In clinical trials, the number of participants taking Contrave who lost 5 to 10% of their body weight exceeded the number of participants with similar weight loss taking a placebo. For a 300-pound person, 5% equals 15 pounds and 10% equals 30 pounds.
Cost
Before insurance or manufacturer’s discounts, Contrave costs around $668 for a 1-month supply of the maintenance dose (2 tablets twice a day) per drugs.com. There are currently no generic versions of Contrave approved for weight loss.
Common side effects
Some side effects of Contrave include nausea, constipation, and vomiting. Taking Contrave can also increase your risk of seizures and mental health complications like suicidal thoughts. Higher dosages of Contrave increase your likelihood of side effects and complications. Contrave can cause withdrawal symptoms, so only stop taking it according to your healthcare provider’s instructions. See the Contrave medication guide for a complete list of side effects or talk to your healthcare provider or pharmacist.***
Safety warning
Suicidal thoughts or actions. One of the ingredients in Contrave, bupropion has caused some people to have suicidal thoughts or actions or unusual changes in behavior. Bupropion may increase the risk of suicidal thoughts or actions in some children and teenagers. Please talk with your healthcare provider if you notice any changes while taking Contrave.
Rating
Contrave has a rating of 6.6/10 among consumers.
Adipex-P is one of the oldest oral prescription weight loss medications available on the market. It was approved by the FDA in 1959 for short-term weight loss management for up to 12 weeks for people 16 years and older. It’s approved when combined with a reduced-calorie meal plan and increased physical activity for adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition. Dosing is 15 to 37.5 milligrams daily taken as a pill 1 to 2 hours after breakfast.
How it works
Phentermine is a stimulant and the active drug in Adipex-P and another brand name drug, Lomaira. While experts aren’t certain how it helps with weight loss, they suspect it affects the brain’s reward system by suppressing appetite.
Effectiveness
In a retrospective cohort study of Adipex-P, 62% of patients lost at least 3% body weight in 3 months with phentermine. 3% weight loss for a 300-pound person is 9 Pounds.
Cost
A 30 day-supply of 37.5 milligram tablets of Adipex-P costs roughly $80, Adipex-P is one of the more affordable prescription weight loss pills. A generic phentermine, in the form of a disintegrating oral tablet, is available at $12 for 7 tablets ($28 for a 28-day supply). (Costs per drugs.com.)
Side effects
Adipex-P is noted to cause more side effects than newer weight loss medications on the market. These include heart disease, lung disease, high blood pressure, and low blood sugar for people taking specific diabetes medications. If you stop taking Adipex-P suddenly, especially from a high dosage, you may experience withdrawal symptoms, including seizures. See the Adipex-p medication guide or talk with your healthcare provider or pharmacist for more information.***
Dependency warning: Adipex-P is a Schedule IV controlled substance and has a high risk for addiction, especially if misused. Don’t take it more often or at higher doses than prescribed, as this increases the risk of developing dependency.
Rating
Adipex-P has an average user rating of 8.9/10 on drugs.com.
Plenity is an oral capsule that helps with weight loss. It was FDA-cleared in April 2019 as an aid that takes up space in your stomach and helps you feel fuller at mealtime and throughout the day. It’s cleared to be used by adults with a BMI of 25 to 40 for weight management when combined with a reduced-calorie meal plan and increased physical activity.
How it works
Plenity is considered a medical device and not a medication because it works “mechanically” inside your stomach. Plenity is made of natural cellulose and citric acid. It absorbs the water in your stomach and mixes with the food you eat, which causes the capsule to expand and take up space in your stomach. It causes you to feel full and reduces your urge to eat. You take 3 capsules orally with 2 cups of water before lunch and dinner. While it makes you feel full, Plenity is not a meal replacement and has no nutritional value.
Effectiveness
Alongside a reduced-calorie diet and exercise program, Plenity caused trial participants to lose an average of 6.4% of their body weight in 6 months. That equals a loss of 19 pounds for a 300-pound person.
Cost
Plenity costs $98 for a 4-week supply according to the manufacturer’s website. There’s no generic equivalent for Plenity.
Side effects
Most of Plenity’s side effects outlined in the medication guide involve the digestive system and include diarrhea, bloating, and stomach pain.* For more information, talk to your healthcare provider or pharmacist.***
Rating
Plenity has an overall rating of 4/5 based on user feedback according to aging.com.
Xenical is a prescription weight-loss medication that contains orlistat. Xenical earned FDA approval in March 1999 for weight management in adults with a BMI over 30 or a BMI equal to or more than 27 with at least one weight-related health condition when combined with a reduced-calorie meal plan and increased physical activity.
An over-the-counter version of orlistat, sold as Alli, is a lower dose (60 g capsule) of orlistat than Xenical (120 mg capsule). Both Xenical and Alli are taken 3 times a day.
How it works
Orlistat is a lipase inhibitor, which causes the lipases (enzymes that break down fat) in the gastrointestinal tract to absorb less dietary fat. Therefore, you absorb less of the fat you eat. Xenical should be taken with a meal containing fat.
Effectiveness
When taken consistently, Xenical stops you from absorbing around 30% of the fat in your diet. In one study on the long-term efficacy and safety of anti-obesity treatment, Xenical use resulted in an average of 2.4% body weight loss in 4 years. That’s a loss of 7 pounds for a 300-pound person.
Cost
Before insurance or manufacturer’s discounts, Xenical costs $803 for a one-month supply according to drugs.com.
Side effects
Xenical has a few mild side effects, like spotting in your underwear or gas when you first start taking it. More serious side effects include liver and kidney problems. See the Xenical medication guide for details and talk with your healthcare provider or pharmacists if you have any questions.***
Rating
Most people’s reviews and ratings on their experience with Xenical have been positive, earning the drug a consumer rating of 8.3/10 on drugs.com.
Note that if you’re not a candidate for prescription weight loss medications, your healthcare provider or pharmacist may recommend over-the-counter weight loss pills that are available without a prescription.
Several potential new weight loss medications are in ongoing clinical trials. Those approved by the FDA should be on the market in the coming months and years.
Before any medication or drug is made available to consumers, it goes through a drug review process that includes clinical research and/or clinical trial phases overseen by the FDA. These phases ensure that the medication is safe to take and works as intended.
During each phase, researchers gather important information on drug safety and effectiveness.
Not all drugs that go through trial phases earn FDA approval. Traditional approval requires that clinical benefit is shown before approval is granted. Accelerated approval is given to some new drugs for serious and life-threatening illnesses that lack available safe and efficacious treatments.
Anti-obesity medications in the later stages of clinical research include the following, ordered from most effective to least effective for weight loss based on current trial data.
Retratrutide activates 3 receptors in the gut: GIP, GLP-1, and glucagon. GIP is a hormone in your intestines that stimulates insulin and glucagon secretion. GLP-1 is a gut hormone your body releases when you eat to stimulate insulin release, regulate blood sugar, and help you feel full. Glucagon prevents your blood sugar from dropping too low. By activating receptors for these hormones, retratrutide reduces hunger and cravings while helping you feel fuller longer.
Currently in phase III trials, retratrutide could be the next breakthrough in obesity medicine. Retratrutide is set to complete clinical trials by early 2026.
Trials indicate that retratrutide may help people lose up to 24% of their initial body weight in 11 months. That’s a significant loss of 72 pounds for a starting weight of 300 pounds. Compare that to the 15% average weight loss (or 27 fewer pounds for a 300-pound person) in 6 months with Wegovy. It also reduces fat in the liver, showing promising results for people who have fatty liver disease, which may lead to liver damage.
Another GLP-1 agonist, mazdutide is in phase II trials. It is being studied for its effect on weight loss and type 2 diabetes. It’s a once-weekly injectable medication set to complete trials in 2024 or 2025.
So far, research indicates that 11 months of consistent mazdutide use helped participants lose almost 19% of their body weight – that’s 57 pounds for a 300-pound person. Other benefits include reducing triglycerides, liver fat content, and low-density lipoprotein (LDL) cholesterol. High triglycerides, liver fat, and cholesterol are all adverse health risks that often occur alongside obesity and individually and can negatively impact health.
Survodutide is a dual glucagon/GLP-1 receptor dual agonist. It activates both GLP-1 and glucagon receptors to reduce hunger and cravings while increasing feelings of fullness when someone eats. It’s a once-weekly injection currently set to complete phase III trials in 2026.
Results of phase II studies suggest survodutide can help people lose up to 19% of their initial body weight in 10 months or 57 pounds if you start at 300 pounds.
CagriSema is an emerging weight-loss injection currently undergoing clinical trials, scheduled to be complete in 2026.
CagriSema is a combination of 2 weight loss medications: cagrilintide and semaglutide. Cagrilintide is a long-acting amylin analog that enhances semaglutide’s weight loss effects, which helps you feel full after you eat. Semaglutide is a GLP-1 agonist that lowers blood sugar levels and reduces appetite.
Taken once a week, CagriSema may help people lose up to 15% of their initial body weight, which is 45 pounds if you start at 300 pounds.
Like semaglutide, ecnoglutide is a GLP-1 agonist. Injectable ecnoglutide is currently in phase III trials in China while an oral version is in phase I trials. Trials for ecnoglutide are set to run until late 2024 or early 2025.
Early clinical data for ecnoglutide show that it may help people lose up to 15% of their body weight in 6 months, which equals 45 pounds for someone who weighs 300 pounds.
Bimagrumab is an activin type II receptor (ActRII) antagonist currently in phase II clinical trials for the treatment of obesity and other cardiometabolic diseases. Researchers are examining its effects when taken alone and in combination with Wegovy. Phase II trials run until June 2025.
Unlike the other medications on this list, Bimagrumab is a biologic medication. Biologics are made from organic components, like proteins or organisms, rather than being chemically synthesized like most drugs. Biologics include many vaccines and medications or treatments used for a variety of conditions.
Bimagrumab is a monoclonal antibody that targets the activin type II receptors. Activin is a hormone that stimulates cells in the pancreas to improve insulin resistance and help you lose fat.
Bimagrumab is being investigated primarily for the treatment of muscle wasting conditions and disorders involving muscle weakness. Bimagrumab works by blocking the activity of myostatin, a protein that inhibits muscle growth, to promote muscle growth and strength. Bimagrumab also blocks activin receptors to support weight loss and increase lean muscle mass.
In clinical trials, bimagrumab has helped adults who are overweight and have type 2 diabetes lose 6 to 7% of their total body weight — that’s 18 to 21 pounds for a 300-pound person. Trial participants have also seen an average 3% increase in lean muscle mass, setting bimagrumab apart from other upcoming weight loss drugs.
The FDA-approved weight loss pills and injections listed in this article require a prescription, so before you can get one, talk with a licensed healthcare provider. You can find a qualified provider for affordable and transparent online or in-person care on the Klarity platform.
After evaluating your health and goals, your healthcare provider will create an individualized program for safe and successful weight loss. Based on your needs, your plan might include prescription medications. You can fill your prescription at a trusted local pharmacy or get your prescription weight loss pills online through a reputable online pharmacy.
Some local pharmacies conveniently offer delivery through DoorDash and similar delivery options that bring your prescriptions directly to your home.
Online pharmacies, like Amazon, Express Scripts, CVS Caremark, and Centerwell, mail your order to your home. While reviewing options for online pharmacies, consider using this guide from the FDA on how to buy medicines safely from an online pharmacy.
If you’re struggling to lose weight, a healthcare provider can help get you on track. On Klarity, find a weight-loss specialist to help you decide if a medication-managed weight loss program is the right approach for you. Find a provider on Klarity today.
***When using any medication covered here, contact your healthcare provider if you have any severe allergic reactions or stomach pains. Please note that side effects listed here are not complete lists of side effects, and others may occur. Call your healthcare provider for medical advice about side effects. You may report side effects to the FDA by calling 1-800-FDA-1088.
The information provided in this article is for educational purposes only and should not be construed as medical advice. Always seek the guidance of a qualified healthcare professional with any questions or concerns you have regarding your health.
How we reviewed this article: This article goes through rigorous fact-checking by a team of medical reviewers. Reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the author.
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