Farmin Shahabuddin, MPH, Jenny Niwa, and Diana Zuckerman, Ph.D, National Center for Health Research
Weight loss drugs are advertised everywhere and often in the news, especially the newer drugs such as Wegovy, Ozempic, Mounjaro, and Zepbound. All of these drugs are more effective than older weight loss drugs that the Food and Drug Administration (FDA) previously approved (such as Saxenda, Qsymia, Contrave, Xenical, Alli, and Phentermine). Although Ozempic and Mounjaro are approved for diabetes and not weight loss, all these drugs are being used to lose weight. Before you decide whether to take any of them, here are some things you should know.
What are these drugs and how do they work?
The FDA approved Ozempic in 2017 and Mounjaro in 2022, both for type 2 diabetes. For weight loss, the FDA approved Wegovy in 2021 and Zepbound in late 2023. In 2024, Wegovy was also approved to reduce heart attack and stroke risk in overweight or obese adults,[1] which made it more likely to be covered by health insurance policies. Ozempic and Wegovy contain semaglutide, while Mounjaro and Zepbound contain tirzepatide. Despite different ingredients, they all work by mimicking a natural hormone called GLP-1, which slows digestion so people feel full longer and which also helps control blood sugar.
These drugs were originally only available as weekly shots. In December 2025, the FDA approved a pill version of Wegovy, making it the first GLP-1 weight-loss drug in pill form. It has been in pharmacies since January 2026.
Saxenda, which contains liraglutide, is another GLP-1 drug that is a daily shot and generally leads to less weight loss.[2] Foundayo (orforglipron) is another GLP-1 weight loss pill that was approved by the FDA in April 2026. As a newer drug, there is less information about its safety or effectiveness.
What About Cheaper “Compounded” Versions?
During 2022 to 2024, when these drugs were in short supply, the FDA allowed “compounding” pharmacies to make their own versions at lower prices. These compounded versions were not evaluated or approved by the FDA, so their safety and effectiveness were not guaranteed. Ever since the shortage ended in February 2025, the FDA began to take action against these compounded pharmacy versions, such as the widely advertised Hims & Hers versions.[3] The FDA has warned that these compounded drugs are not FDA-approved and their quality and safety cannot be guaranteed.
What are the benefits?
In clinical trials, people who stayed on these drugs for about a year lost an average of 15% of their body weight on semaglutide (Wegovy) and about 21% on tirzepatide (Zepbound), compared to about 2 to 3% for those on a placebo (fake pill). [4] However, in the real world, results are often less impressive because many people stop early or use lower doses. For example, a 2025 U.S. study of nearly 8,000 adults found that those who stayed on the drugs for a full year lost about 12% of their body weight, while those who stopped early lost only about 4 to 7%.[4]
A 2025 U.S. study of more than 30,000 patients with severe obesity found that GLP-1 patients lost about 10% of their weight, while patients who underwent weight loss surgery lost about 28%. Nearly all surgery patients (96 out of 100) kept off at least 10% of their weight, compared to only 46 out of 100 on drugs.[5] Surgery also cost about $12,000 less over two years because there were no ongoing drug costs. However, surgery is a major operation and is not right for everyone.
In 2023, there was major media coverage saying Wegovy reduced heart attacks, strokes, and deaths by 20%. But when we carefully looked at the actual numbers from a 2023 study of 17,500 people with obesity and heart disease, we realized that out of every 100 people, about 8 on a placebo (fake) pill had a serious heart event compared to about 6.5 on Wegovy.[6] Although 6.5 is 20% lower than 8, 1.5% is a very small difference for patients. More recently, a 2026 U.S. study of nearly 300,000 adults with type 2 diabetes found that 1% of patients taking semaglutide or tirzepatide had similar heart outcomes. About 1 out of every 100 people in each group had a heart attack, stroke, or died within one year.[7]
A 2025 study evaluated 2,510 U.S. veterans with irregular heartbeat (atrial fibrillation), diabetes, and obesity for 3 years. Those taking GLP-1 drugs had about 13% fewer hospitalizations and procedures related to their irregular heartbeat, compared to those on other diabetes drugs.[8]
Keep in mind that these studies showing health benefits focused on people who stayed on the drugs for 1 to 3 years, but most people stop within a year and gain most if not all of the weight back. Health benefits are unlikely during the first year, and even less likely after the weight is regained. Also, many studies only included people with diabetes, so the results may differ for those taking these drugs just for weight loss.
Side Effects, Complications and Unknown Risks
The most common side effects are stomach problems like nausea and diarrhea. Some people experience severe vomiting or stomach paralysis, which is why many stop taking these drugs within months. Other possible serious side effects listed on the drug companies’ websites include inflammation of the pancreas, gallbladder problems, low blood sugar, kidney problems, serious allergic reactions, increased heart rate, and depression or thoughts of suicide.[9] However, research on many of these side effects is still limited, and more studies are needed to fully understand how common or serious they are.
There are several rare but serious concerns. People taking semaglutide (Ozempic and Wegovy) can develop a serious eye condition that can cause sudden, painless vision loss that is often permanent, according to a 2024 U.S. study that first found this connection[10], and a larger 2026 study of over 102,000 U.S. veterans confirmed the finding.[11] If you notice any sudden changes in your vision, tell your eye doctor right away.
GLP-1 drugs carry an FDA warning about a possible connection to thyroid cancer, based on animal studies. However, the evidence in humans is mixed. A large 2025 study by Novo Nordisk (the maker of Wegovy and Ozempic) analyzed data from over 100,000 people in clinical trials and found no increased rate of thyroid cancer compared to those on other medications. Other studies have reached similar conclusions. Still, the FDA warning remains, and if you or a family member has ever had a certain type of thyroid cancer (medullary thyroid carcinoma), these drugs should not be used.[12]
There are also concerns about bone health. A 2026 study of over 146,000 U.S. adults with obesity and type 2 diabetes followed them for five years and found that about 4 out of every 100 people on GLP-1 drugs developed osteoporosis (weak and brittle bones), compared to about 3 out of 100 not taking the drugs.[13] That is a small difference, but to avoid osteoporosis, doctors recommend eating well, exercising, and getting your bone health checked while on these drugs.
Another thing to be aware of is how these drugs affect medical procedures. Since GLP-1 drugs slow how fast your stomach empties, it is best not to take them prior to surgery. Vomiting under anesthesia can be dangerous because food and stomach acid can get into the lungs, and patients taking GLP-1 drugs were much more likely to have food in their stomach than those who stopped the one dose before surgery.[14] However, switching to clear liquids the day before may prevent this problem. If you are scheduled for surgery or a medical procedure, talk to your doctor about your GLP-1 medication beforehand.
In 2026, an article in the New England Journal of Medicine raised concerns about the misuse of GLP-1 drugs by individuals with eating disorders who are not overweight. [15] That is a different type of concern that needs to be considered.
Keep in mind that there are still many unknowns about these drugs. Brain scans show how they affect the brain, so researchers are starting to study the long-term changes that might result. There are many reports of changes in mood (such as depression), concentration, and other reported changes that are sometimes positive (such as less interest in alcohol) and sometimes negative (feeling less motivated). Research is needed to better understand if these changes are due to the medications or other issues, and if some people are more likely to benefit than others. Since children’s brains are still developing, the long-term impact on children and young adults is especially important to study.
What happens when you stop taking these drugs?
Many studies, including a 2026 U.S. study of nearly 127,000 adults without diabetes, confirmed that most people taking GLP-1 drugs stopped within a year, usually because of the side effects or cost.[16] Only about 25% stayed on any GLP-1 drug after 12 months. About 20% switched to a different GLP-1 drug during that time.[16]
When people stop, the weight comes back quickly. A 2022 study of nearly 2,000 adults found that people gained back about two-thirds of their weight loss within a year of stopping Wegovy.[17] A 2026 review of 37 studies found that people who stopped these drugs gained back about 22 pounds in a year, compared to just 2 pounds for those who stopped diet and exercise programs.[18] Even those who stay on the drugs usually stop losing weight after about a year.
There is still much that is unknown about these drugs. It is unclear how they affect patients after years of use, or what percentage of people will only benefit if they stay on the drug for the rest of their lives.[16] In short, these drugs work while you take them, but the benefits fade once you stop.
Are you being sold a product or a medical solution?
With so much money being spent on advertising, it is worth considering how that might influence your impression of these drugs. In 2025, Novo Nordisk spent about $487 million advertising Wegovy and Ozempic, which is more than double what Eli Lilly spent on Zepbound and Mounjaro.[19] When drug companies spend hundreds of millions on advertising, it is worth asking: are you being unduly influenced by the hype of ads and media coverage?
How much do these drugs cost?
U.S. list prices run about $1,350/month for Wegovy, $1,000 for Ozempic, and $1,086 for Zepbound.[20] However, most people do not pay full price. In late 2025, drug companies made deals with the government to lower costs.Without insurance, the Wegovy pill costs about $149 to $299 per month, the standard Wegovy shot about $349/month, and a newer higher-dose Wegovy shot (Wegovy HD) costs $399/month, which is about 40% less than the top doses of Zepbound. Zepbound shots cost $299 to $449/month.[21]
With private insurance, you may pay as little as $25/month using a discount card offered by the drug company that lowers your out-of-pocket cost. Medicare covers these drugs for diabetes, heart disease prevention, or sleep apnea, but not weight loss alone. That may change starting in July 2026, where some Medicare patients may get these drugs for weight loss for about $50/month.
Are these drugs right for you?
If you or a family member has ever had a type of thyroid cancer, taking any of the GLP-1 drugs may be dangerous. If you are sensitive to stomach problems, these drugs may not be right for you. These drugs are meant for serious conditions like obesity and type 2 diabetes, not cosmetic weight loss.
The media attention to these drugs makes it seem that they are the only FDA-approved weight loss drugs. They are not. However, all weight loss drugs have unpleasant and potentially serious side effects, and these newer drugs seem to be more effective. If you are eligible and interested in taking these drugs, you should first and foremost make sure to talk to your physician and discuss what to expect, the possible side effects, and your medical history. Keep in mind, as we said earlier, that these are relatively new drugs, they affect the brain, and we don’t yet know all the risks or benefits. Meanwhile, there are other methods available that can help you lose weight and improve your health if you stick with them. These include exercising daily or regularly, developing healthier eating habits, and knowing when to eat.
References
[1] U.S. Food and Drug Administration. (2024, March 8). FDA approves first treatment to reduce risk of serious heart problems specifically in adults with obesity or overweight. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-reduce-risk-serious-heart-problems-specifically-adults-obesity-or
[2] National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Prescription medications to treat overweight & obesity. https://www.niddk.nih.gov/health-information/weight-management/prescription-medications-treat-overweight-obesity
[3] U.S. Food and Drug Administration. (2026, February 6). FDA intends to take action against non-FDA-approved GLP-1 drugs [Press release]. https://www.fda.gov/news-events/press-announcements/fda-intends-take-action-against-non-fda-approved-glp-1-drugs
[4] Gasoyan, H., et al. (2025). Changes in weight and glycemic control following obesity treatment with semaglutide or tirzepatide by discontinuation status. Obesity. https://doi.org/10.1002/oby.24331
[5] West, S., Scragg, J., Aveyard, P., Oke, J. L., Willis, L., Haffner, S. J. P., Knight, H., Wang, D., Morrow, S., Heath, L., Jebb, S. A., & Koutoukidis, D. A. (2026). Weight regain after cessation of medication for weight management: systematic review and meta-analysis. BMJ (Clinical research ed.), 392, e085304. https://doi.org/10.1136/bmj-2025-085304
[6] Lincoff, A. M., Brown-Frandsen, K., Colhoun, H. M., Deanfield, J., Emerson, S. S., Esbjörnsson, S., Hardt-Lindberg, S., Hovingh, G. K., Kahn, S. E., Kushner, R. F., Lingvay, I., Oral, T. K., Michelsen, M. M., Plutzky, J., Tornoe, C. W., & Ryan, D. H. (2023). Semaglutide and cardiovascular outcomes in obesity without diabetes. New England Journal of Medicine, 389(24), 2221–2232. https://doi.org/10.1056/NEJMoa2307563
[7] Krüger, N., Schneeweiss, S., Desai, R. J., Sreedhara, S. K., Kehoe, A. R., Fuse, K., Hahn, G., Schunkert, H., & Wang, S. V. (2026). Cardiovascular outcomes of semaglutide and tirzepatide for patients with type 2 diabetes in clinical practice. Nature medicine, 32(1), 342–352. https://doi.org/10.1038/s41591-025-04102-x
[8] Heart Rhythm Society. (2025, April 26). New study finds GLP-1 receptor agonists may reduce atrial fibrillation-related events in patients with obesity [Press release]. https://heartrhythm.com/heart-rhythm-media-room/glp1-study-reduces-afib-events
[9] Novo Nordisk. (n.d.). Tips for managing common side effects. Wegovy®. https://www.wegovy.com
[10] Hathaway, J. T., Shah, M. P., Hathaway, D. B., Zekavat, S. M., Krasniqi, D., Gittinger, J. W., Cestari, D., Mallery, R., Abbasi, B., Bouffard, M., Chwalisz, B. K., Estrela, T., & Rizzo, J. F. (2024). Risk of nonarteritic anterior ischemic optic neuropathy in patients prescribed semaglutide. JAMA Ophthalmology, 142(8), 732–739. https://doi.org/10.1001/jamaophthalmol.2024.2296
[11] Heberer, K., Bress, A. P., Cogill, S., Maldonado, A. I., Kim, S. H., Nallamshetty, S., Chen, Y. Q., Shih, M. C., Lynch, J. A., & Lee, J. S. (2026). New-Onset Nonarteritic Anterior Ischemic Optic Neuropathy and Initiators of Semaglutide in US Veterans With Type 2 Diabetes. JAMA ophthalmology, 144(3), 259–264. https://doi.org/10.1001/jamaophthalmol.2025.6262
[12] Vilsbøll, T., et al. (2026). Assessment of thyroid cancer risk associated with glucagon-like peptide-1 receptor agonist use. Diabetes, Obesity and Metabolism. https://doi.org/10.1111/dom.70291
[13] Horneff, J., et al. (2026). GLP-1 receptor agonist use and musculoskeletal outcomes [Conference presentation]. American Academy of Orthopaedic Surgeons Annual Meeting. Reported in: Bernstein, L. (2026, March 8). Bone injury risk weight loss drugs. The Washington Post. https://www.washingtonpost.com/health/2026/03/08/bone-injury-risk-weight-loss-drugs/
[14] Ahmad, A. I., Garg, S., Jacobs, J., Ansari, Z., Al-Din, T. J., Almomani, A., Valencia, S., Vargo, J., Chatterjee, A., Siddiki, H., Hong, L., Nicolas, M. A., Miller, A., & Shah, T. (2026). Holding vs Continuing GLP-1/GIP Agonists Before Upper Endoscopy: The OCULUS Randomized Clinical Trial. JAMA internal medicine, 186(5), 578–584. https://doi.org/10.1001/jamainternmed.2026.0027
[15] Banks A. (2026). GLP-1 Receptor Agonists and Eating Disorders – Cause for Concern. The New England journal of medicine, 394(17), 1665–1667. https://doi.org/10.1056/NEJMp2600300
[16] Xie, L., Anazco, D., Chancay, A. H., Mathew, M. S., Francis, J. M., Almandoz, J. P., & Messiah, S. E. (2026). Glucagon-Like Peptide-1 Receptor Agonist Switching and Treatment Persistence in Adults Without Diabetes. JAMA network open, 9(3), e261272. https://doi.org/10.1001/jamanetworkopen.2026.1272
[17] Wilding, J. P. H., Batterham, R. L., Davies, M., Van Gaal, L. F., Kandler, K., Konakli, K., Lingvay, I., McGowan, B. M., Oral, T. K., Rosenstock, J., Wadden, T. A., Wharton, S., Yokote, K., & Kushner, R. F. (2022). Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, Obesity and Metabolism, 24(8), 1553–1564. https://doi.org/10.1111/dom.14725
[18] The GLP-1 Agonist Plateau No One’s Talking About. (2023, September 22). https://www.medpagetoday.com/special-reports/exclusives/106464
[19] Varghese, H. M., & Wingrove, P. (2026, January 28). Novo’s Wegovy and Ozempic US advertising spend doubles rival Eli Lilly, data shows. Reuters. https://www.reuters.com/business/media-telecom/novos-wegovy-ozempic-us-advertising-spend-doubles-rival-eli-lilly-data-shows-2026-01-28/
[20] Florko, N. (2023). Novo Nordisk bought prescribers over 450,000 meals and snacks to promote drugs like Ozempic. STAT+. https://www.statnews.com/2023/07/05/ozempic-rybelsus-novo-nordisk-meals-for-doctors/#:~:text=Novo%20Nordisk%20bought%20prescribers%20over,to%20promote%20drugs%20like%20Ozempic&text=WASHINGTON%20%E2%80%93%20Novo%20Nordisk%20spent,weight%20loss%2Dinducing%20diabetes%20drugs
[21] Amin, K., Telesford. I., Singh, R., & Cox, C. (2023). How do prices of drugs for weight loss in the US compare to peer nations’ prices? Health System Tracker. https://www.healthsystemtracker.org/brief/prices-of-drugs-for-weight-loss-in-the-us-and-peer-nations/?utm_campaign=morning_rounds&utm_medium=email&_hsmi=270760455&_hsenc=p2ANqtz-_P2SZN9DLjS_l7fSn8hrgS8xRf4YvJIonV0X-iRtKF3FtcWbgsMJd-K6tDV2u12XNFMEesDCulwlbdwkw74D1S-2WqXQ&utm_content=270760453&utm_source=hs_email#List%20prices%20of%20drugs%20used%20for%20weight%20loss%20in%20the%20U.S.%20and%20peer%20nations