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GLP-1 vs bariatric surgery: how do weight loss, risks, cost and coverage compare in the US?

What the US surgical guidance, a 65,000-patient study and the medicine trials show, and how Medicare treats each. Not a recommendation.

GLP Guidebook teamPublished Oct 14, 20269 min read18 sourcesWritten from published sources
What we checked18 sources, each one opened and linked to the sentence it supportsLast checked Oct 14, 2026 · Next review due Oct 14, 2027 · How we write

Written for the United States. Reading from India? India version

The short answer

No trial has compared bariatric surgery with GLP‑1 medicines yet. In separate studies, weight fell 19% to 26% five years after surgery, with major problems in 3 to 5 in 100 within 30 days, and 15% to 21% in Wegovy and Zepbound trials of under 2 years, where 5 to 7 in 100 stopped for side effects. Medicare covers surgery; for weight-loss drugs it has only its $50 Bridge.

At a glance

ItemBariatric surgeryGLP‑1 medicines
What it isAn operation on the stomach, most often a sleeve gastrectomy or a gastric bypass3Weekly injections or daily pills, such as Wegovy (semaglutide, Novo Nordisk) and Zepbound (tirzepatide, Eli Lilly)9,10
Who it’s for in US guidanceASMBS 2022: BMI 35 or more; considered at BMI 30 to 34.9 with metabolic disease; 27.5 or more in Asian people1US labels: BMI 30 or more, or 27 or more with a weight-related condition9,10
How it’s doneOne operation, then lifelong healthy habits, medical follow-up and extra vitamins and minerals5A weekly shot (or a daily pill) for as long as it’s taken9,10
Dose stepsNone: one operationWegovy: 0.25 mg rising every 4 weeks to 2.4 mg. Zepbound: 2.5 mg, then up 2.5 mg at a time to 5 to 15 mg9,10
Average weight change, with the harm beside it25.5% (bypass) and 18.8% (sleeve) after 5 years in 65,093 US patients. Major problems within 30 days: 5.0 and 2.6 in 100314.9% on Wegovy (68 weeks) and 20.9% on Zepbound 15 mg (72 weeks). Side effects made about 5 to 7 in 100 stop, against about 3 on placebo6,7,9,10
Most common side effectsEarly: bleeding, infection, leaks, diarrhea, blood clots. Later: low vitamins and minerals, gallstones, narrowing, hernias4Nausea, diarrhea, vomiting and constipation, mostly while the dose goes up9,10
PriceNo list price: hospitals and surgeons set their own charges, and we found no official priceWegovy $349 a month ($4,537 a year); Zepbound $299 to $699 a month by dose (about $3,887 to $9,087 a year at one dose)14,15
CoverageMedicare covers it with a BMI of 35 or more, a related condition and failed medical treatment2Medicare can’t cover weight-only use, except the $50 GLP‑1 Bridge; employer coverage varies12,13,16

Not a ranking. The surgery figures come from an observational study of US health records; the medicine figures come from separate randomized trials. No head-to-head result exists yet. Prices are the makers’ regular self-pay prices, checked Oct 14, 2026; a year is 13 four-week fills (our arithmetic).

Key takeaways

  • In a study of 65,093 US patients, average weight loss 5 years after surgery was 25.5% after gastric bypass and 18.8% after sleeve gastrectomy.3
  • In separate trials, adults lost 14.9% on Wegovy over 68 weeks and 20.9% on tirzepatide 15 mg over 72 weeks.6,7
  • Major problems within 30 days of surgery affected 5.0 in 100 people after bypass and 2.6 in 100 after sleeve in that US study.3
  • Two US records-based studies, not trials, compared people who chose each treatment. In one, average loss 2 years on was 22.4% to 28.1% after surgery and 6.5% to 10.8% after starting semaglutide or tirzepatide; neither study reported complications, and neither can show cause.17,18
  • A year after stopping semaglutide in a STEP 1 extension, people had regained about two-thirds of the weight they had lost.8
  • Medicare covers bariatric surgery for people with a BMI of 35 or more and a related health problem, but can’t cover weight-loss drugs outside its $50 Bridge.2,12,13
Before you go further
  • This compares guidance, studies and labels. It doesn’t say which suits you, and we don’t recommend either: your doctor and surgeon decide with you.
  • Medicine prices are the makers’ published self-pay prices, never a seller’s. We don’t name or price hospitals or surgeons.
  • Both carry real risks: see below and our side effects guide.
On this page
  1. How do surgery and GLP‑1 medicines work differently?
  2. Who is each one for in the US?
  3. Which leads to more weight loss?
  4. What are the risks of each?
  5. What do they cost, and does insurance pay?
  6. Which one? What does a doctor weigh?
  7. Questions people ask
  8. How we researched this
  9. Sources

How do surgery and GLP‑1 medicines work differently?

Surgery changes the stomach and gut for good; GLP‑1 medicines copy gut hormones that slow the stomach and reduce hunger only while you take them.4,8,9

A sleeve gastrectomy removes most of the stomach. A gastric bypass makes a small stomach pouch and reroutes the small intestine. In the large US study below, 95 in 100 operations were one of these two (our arithmetic).3

GLP‑1 medicines copy GLP‑1, a hormone your gut releases after eating. Tirzepatide also copies a second hormone, GIP.9,10 In a STEP 1 extension, much of the weight lost came back within a year of stopping.8

Who is each one for in the US?

US surgical guidance recommends surgery from a BMI of 35, while the medicine labels start at a BMI of 30, or 27 with a weight-related condition.1,9

BMI (body mass index) is your weight in kilograms divided by your height in meters squared. In 2022, the ASMBS and IFSO surgical societies updated decades-old rules:1

  • Surgery is recommended at a BMI of 35 or more, with or without other health problems.1
  • It should be considered at a BMI of 30 to 34.9 with metabolic disease, such as type 2 diabetes.1
  • For Asian people, thresholds are lower: surgery should be offered from a BMI of 27.5.1

The Wegovy and Zepbound labels are for adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition.9,10 These are points to start a conversation, not a sign of eligibility. Our post on BMI cut-offs for Asian Americans covers the lower thresholds, and the BMI and waist tool works out your number.

Which leads to more weight loss?

No trial has compared them directly yet. The surgery and medicine figures below come from separate studies with different people and designs, so they can’t be set against each other; two records-based studies that looked at both groups together can’t show cause either.3,6,7,17,18

Surgery. A study of 65,093 US patients in 41 health systems tracked weight after surgery. Average loss after 1 year was 31.2% of body weight for bypass and 25.2% for sleeve. After 5 years it was 25.5% and 18.8%.3 It used health records, not random groups, so other differences between patients may affect the results.3

Medicines. In STEP 1, adults lost 14.9% on Wegovy 2.4 mg over 68 weeks, against 2.4% on a dummy injection (placebo).6 In SURMOUNT-1, adults lost 20.9% on tirzepatide 15 mg over 72 weeks, against 3.1% on placebo.7 For someone starting at 260 lb (118 kg), 20% is about 52 lb (24 kg): our arithmetic. Averages hide a wide range.

No head-to-head result yet. A US randomized trial comparing surgery with semaglutide and tirzepatide began in January 2025. It plans to enroll about 140 people, with main results expected after July 2027.11

Two records-based comparisons. Two US studies looked back at health records of adults with a BMI of 35 or more who had surgery or were prescribed a GLP‑1 medicine. These are observational studies, not trials: people and their doctors chose the treatment, so the groups may differ in ways the researchers couldn’t adjust for. Both found more weight loss in the surgery groups; neither can show that the treatment caused the difference, and neither reported complications or side effects.17,18

  • New York health records, 2018 to 2024 (Obesity, 2026; first presented at the ASMBS meeting in 2025). Of 44,025 adults, average weight loss 2 years after treatment was 22.4% after sleeve gastrectomy, 28.1% after gastric bypass, 6.5% after starting semaglutide and 10.8% after starting tirzepatide. A third of medicine users (33.9%) stopped after two monthly prescriptions. In people prescribed a medicine for a full year without a break, loss at 2 years was 8.0% on semaglutide and 11.9% on tirzepatide.17
  • The authors’ limits. They couldn’t account for every difference between the groups; they counted prescriptions written, not filled; they didn’t know why each medicine was prescribed; the New York patients may not represent the wider US; and many people had few follow-up weights.17
  • Pennsylvania insurance and health records (JAMA Surgery, 2025). Of 30,458 insured adults, 14,101 had surgery and 16,357 were prescribed a GLP‑1, including older ones such as liraglutide and dulaglutide. Weight records existed for 1,548 of them: average loss at each person’s last recorded weight was 28.3% in 1,291 surgery patients and 10.3% in 257 medicine users. Medtronic paid for consulting and medical writing; the authors say it had no role in the study.18
  • The authors’ limits. Follow-up lasted different lengths of time; weight loss wasn’t measured at one fixed point; the small group with weight records differed from the rest in age, sex and health problems; claims don’t always say why a medicine was prescribed; and not all confounding factors may have been considered.18

After stopping. One year after people stopped semaglutide in a STEP 1 extension, they had regained about two-thirds of the weight they lost. Their net loss fell from 17.3% to 5.6%.8 Our stopping guide explains why.

What are the risks of each?

Surgery carries operation risks and lifelong nutrition needs; the medicines carry mostly stomach side effects plus rarer serious risks, for as long as they’re taken.3,4,9,10

In the US study above, major problems within 30 days of surgery affected 5.0 in 100 people after bypass and 2.6 in 100 after sleeve.3 The surgical societies put the risk of death around the operation at 0.03% to 0.2%, or 3 to 20 in 10,000.1 Within 5 years, about a third of patients need a follow-up procedure, surgery or hospital stay, more often after bypass.4

RisksThe risks, in brief
  • Surgery, early: bleeding, infection, leaks where the stomach or gut is stapled, diarrhea and blood clots in the legs that can travel to the lungs.4
  • Surgery, later: poor absorption of vitamins and minerals, which can lead to anemia and thin bones; gallstones; narrowing of the new connection; hernias; alcohol hitting harder after bypass.4
  • Medicines, stomach effects: 44 in 100 people on Wegovy 2.4 mg felt sick, against 16 in 100 on placebo;9 25 to 29 in 100 on Zepbound, against 8 in 100.10
  • Medicines, serious risks: pancreatitis (an inflamed pancreas), gallbladder problems, and a boxed thyroid warning for people with a personal or family history of medullary thyroid cancer or MEN 2.9,10
  • Medicines and anesthesia: they slow the stomach, so tell the team before any surgery, including weight-loss surgery.9,10
Full detail in our side effects guide →
Get help now: call 911 or go to the ER for severe stomach pain that won’t go away, chest pain or sudden shortness of breath (a clot can travel to the lungs), or swelling of the face or throat.4,9,10
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What do they cost, and does insurance pay?

Medicare covers surgery for people who meet its rules, but can’t pay for weight-loss drugs except through the temporary $50 Bridge.2,12,13

Surgery. Medicare covers it for people with a BMI of 35 or more, at least one related health problem and earlier medical treatment that didn’t work.2 We found no official list price for the operation; hospitals and surgeons set their own charges.

Medicines. Paying cash, Wegovy pens are $349 a month, or about $4,537 a year.14 Zepbound vials and KwikPens are $299 to $699 a month by dose, or $449 at the higher doses if each refill comes within 45 days.15 Medicare Part D can’t cover weight-loss-only use; the $50 GLP‑1 Bridge for weight runs through Dec 31, 2027.12,13 In 2025, 19% of employers with 200 or more workers covered GLP‑1s mainly for weight.16

The medicine costs recur every month. Our post on GLP‑1 costs without insurance works out a year.

Which one? What does a doctor weigh?

We don’t recommend either: a doctor, and often a surgeon, looks at your BMI, your health problems, past attempts, your wishes and what your plan covers.

  • BMI and health problems. Surgery guidance starts at a BMI of 35, or 30 with metabolic disease.1
  • How long the effect needs to last. Surgery is a one-time change; medicine effects fade after stopping.3,8
  • Risk you’re willing to take. Operation risks come up front; medicine side effects are most common while the dose rises, and the medicine is taken long term.3,7,9,10
  • Commitment. After surgery, lifelong vitamins and follow-up are needed.5
  • Coverage. Medicare and many plans treat the two very differently.2,12

Diet and activity changes are the base of both. Our guide to your options sets them side by side.

Questions people ask

Does a GLP-1 work as well as bariatric surgery?

No trial has answered that yet. In separate studies that can’t be compared directly, surgery gave 19% to 26% average weight loss after 5 years, and Wegovy and Zepbound gave about 15% to 21% in trials of under 2 years. Major problems within 30 days of surgery affected 3 to 5 in 100; side effects made 5 to 7 in 100 stop the medicines. Two US records-based studies, which aren’t trials and can’t show cause, found more weight loss in people who chose surgery: in one, 22.4% to 28.1% two years after surgery and 6.5% to 10.8% two years after starting semaglutide or tirzepatide.3,6,7,9,10,17,18

Can you take a GLP-1 instead of bariatric surgery?

That is for a doctor, often with a surgeon, to weigh with you. US guidance recommends surgery from a BMI of 35, and the medicine labels start at a BMI of 30, or 27 with a weight-related condition.1,9

Does Medicare cover bariatric surgery?

Yes, with a BMI of 35 or more, at least one related health problem and earlier medical treatment that didn’t work.2

Does weight come back after stopping a GLP-1?

Often. A year after stopping semaglutide in a STEP 1 extension, people had regained about two-thirds of the weight they had lost.8

Is there a trial comparing surgery and GLP-1s directly?

One US randomized trial started in January 2025, with about 140 people; its main results are expected after July 2027.11

How we researched this

We used the 2022 ASMBS/IFSO surgery guidance, Medicare’s coverage rule for bariatric surgery, a 65,093-patient US study (Annals of Internal Medicine, 2018), two records-based studies comparing surgery with GLP‑1 medicines (JAMA Surgery, 2025; Obesity, 2026), read in full, NIDDK pages on surgery, the STEP 1 and SURMOUNT-1 trials, the current US labels for Wegovy and Zepbound, and the makers’ self-pay prices, all checked on October 14, 2026.1,2,3,4,6,7,9,10,17,18

Pound figures and yearly totals are our arithmetic.

Before you move on

  • Work out your BMI, and know your health problems.
  • Ask what your plan covers: surgery, medicines or both.
  • Ask about lifelong vitamins and follow-up after surgery.
  • Ask what happens to weight if a medicine stops.
  • Tell any surgeon if you take a GLP‑1.
BMI and waist toolStopping a GLP‑1Cost calculatorWho pays: insurance and MedicareAll GLP-1 prices

More comparisons

USUnited StatesZepbound vs Wegovy: which loses more weight, and how do side effects, cost and coverage compare?USUnited StatesOzempic vs Wegovy: same medicine, so what is the difference in dose, weight loss, cost and coverage?USUnited StatesWegovy pill vs Foundayo vs Wegovy injection: how do the GLP‑1 pills differ from the shot?
About GLP Guidebook

The monthly US update

An independent guide to GLP‑1 medicines. We don’t sell medicines, take drug-company money, earn commissions or link to any provider. Once a month: FDA approvals and warnings, Medicare and Medicaid changes, and makers’ price changes. How we write

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Sources

  1. Eisenberg D, et al. 2022 American Society for Metabolic and Bariatric Surgery (ASMBS) and International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO): Indications for metabolic and bariatric surgery. Surg Obes Relat Dis 2022;18:1345-1356. doi:10.1016/j.soard.2022.08.013. PMID 36280539. Link (PDF)
  2. Centers for Medicare & Medicaid Services. National Coverage Determination 100.1: Bariatric surgery for treatment of co-morbid conditions related to morbid obesity (BMI of 35 or more, at least one related condition, earlier medical treatment for obesity unsuccessful). Checked Oct 14, 2026. Link
  3. Arterburn D, et al. Comparative effectiveness and safety of bariatric procedures for weight loss: a PCORnet cohort study. Ann Intern Med 2018;169:741-750. doi:10.7326/M17-2786. PMID 30383139. Funded by the Patient-Centered Outcomes Research Institute. Link
  4. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Bariatric surgery: side effects. Last reviewed September 2020. Link
  5. NIDDK. Bariatric surgery: potential candidates (lifelong healthy habits, medical follow-up and extra vitamins and minerals). Last reviewed September 2020. Link
  6. Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med 2021;384:989-1002. doi:10.1056/NEJMoa2032183. PMID 33567185. Funded by Novo Nordisk. Link
  7. Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med 2022;387:205-216. doi:10.1056/NEJMoa2206038. PMID 35658024. Funded by Eli Lilly. Link
  8. Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab 2022;24:1553-1564. doi:10.1111/dom.14725. PMID 35441470. Link
  9. Novo Nordisk. Wegovy (semaglutide) injection and tablets: US prescribing information. Revised 06/2026. US label. Link
  10. Eli Lilly. Zepbound (tirzepatide): US prescribing information. Revised 08/2026. US label. Link
  11. ClinicalTrials.gov. Bariatric Surgery vs. Semaglutide vs. Tirzepatide (NCT06803888): started Jan 29, 2025; estimated 140 people; estimated primary completion July 2027. Record last updated Sep 3, 2026. Link
  12. KFF. What to know about the BALANCE Model for GLP-1s in Medicare and Medicaid and the Medicare GLP-1 Bridge. May 11, 2026. Link
  13. Centers for Medicare & Medicaid Services. Medicare GLP-1 Bridge: information for prescribers ($50 a month, July 1, 2026 to Dec 31, 2027; covers Foundayo, Wegovy and the Zepbound KwikPen). June 2026. Link
  14. Novo Nordisk. Wegovy price guide (US26NC00049, April 2026): pen $349 a month from 0.25 to 2.4 mg. Checked Oct 14, 2026. Link
  15. Eli Lilly. Zepbound coverage and savings, Self Pay Journey Program terms: regular price for a month of Zepbound vial or KwikPen $299 (2.5 mg), $399 (5 mg), $499 (7.5 mg), $699 (10 to 15 mg); $449 for 7.5 to 15 mg if each refill is within 45 days. Checked Oct 14, 2026. Link
  16. KFF. 2025 Employer Health Benefits Survey (19% of firms with 200 or more workers cover GLP-1s primarily for weight loss). Link
  17. Brown A, et al. Real-world effectiveness of semaglutide and tirzepatide compared with bariatric surgery. Obesity (Silver Spring) 2026;34(8):1583-1591. doi:10.1002/oby.70246. PMID 42345739. Retrospective two-center cohort study (observational); presented at the ASMBS 2025 Annual Scientific Meeting. Funded by the US National Institutes of Health. Link
  18. Barrett TS, et al. Obesity treatment with bariatric surgery vs GLP-1 receptor agonists. JAMA Surg 2025;160(11):1232-1239. doi:10.1001/jamasurg.2025.3590. PMID 40960852. Retrospective cohort study (observational) of insurance claims and health records. Consulting and medical writing funded by Medtronic. Link

Last checked Oct 14, 2026 · Next review due Oct 14, 2027 · Report an error

How this page was made. Written by the GLP Guidebook team from the sources above. It’s general information, not medical advice. Talk to your doctor, pharmacist or prescriber before starting, stopping or changing any medicine. We don’t sell, prescribe or recommend any brand or provider. How we write