Only one trial has ever compared Wegovy® (semaglutide) and Mounjaro® (tirzepatide) head to head: SURMOUNT-5, where tirzepatide produced an average weight loss of 20.2% versus 13.7% for semaglutide. Case closed? Not quite: the trial was open-label, and France’s health authority (HAS) concluded it was not enough to rank one above the other. The right choice depends on your profile, and it is a decision to make with your doctor. Here are the facts, with sources.
⚕️ This article summarizes public data (clinical trials, SmPCs, HAS opinions) for information only. It is not medical advice: only your doctor can recommend a treatment for your situation.
The 30-second version
- Head-to-head (SURMOUNT-5, 72 weeks): −20.2% body weight on tirzepatide vs −13.7% on semaglutide, but the trial was not blinded, a limitation its own authors acknowledge
- France’s HAS: both drugs carry the same rating (ASMR IV); Mounjaro “cannot be ranked” above Wegovy
- Heart: only semaglutide has proven cardiovascular benefit so far (the SELECT trial); tirzepatide’s dedicated results are expected in 2027
- Side effects: very similar digestive profiles; slightly more vomiting with semaglutide, more injection-site reactions with tirzepatide
- In France: identical reimbursement rules for both (BMI, pathway, form); the out-of-pocket amount varies with the maintenance dose
- The decision: your medical profile (heart, sleep apnea, joints, tolerance) matters more than a trial’s average score
SURMOUNT-5: the only real head-to-head
Published in the New England Journal of Medicine in May 2025, SURMOUNT-5 followed 751 adults with obesity and without diabetes for 72 weeks, each on the maximum tolerated dose of one of the two drugs.
At 72 weeks:
- Average weight loss: −20.2% (tirzepatide) vs −13.7% (semaglutide), a 6.5-point gap;
- Waist circumference: −18.4 cm vs −13.0 cm;
- At least 15% body weight lost: 71.7% vs 45.0% of participants; at least 25%: 36.5% vs 18.6% (results posted on ClinicalTrials.gov).
Two important caveats: the trial was open-label (everyone knew which drug they were on, which can influence behavior), a limitation its authors explicitly acknowledge, and it was funded by tirzepatide’s manufacturer.
What France’s HAS concluded: an official draw
In its opinion on Mounjaro for obesity (Transparency Committee, 19 November 2025), the HAS states plainly:
“In the absence of robust comparative data versus WEGOVY (semaglutide) — as the only available comparison of weight-loss effect comes from an open-label study — MOUNJARO (tirzepatide) cannot be ranked against this molecule.” (our translation of the French opinion)
Both drugs receive the same rating: ASMR IV (minor improvement in medical benefit), explicitly on the same footing. In other words: for the French authority there is, today, no “better” drug. There are two valid options.
The heart: semaglutide’s current edge
This is the most solid difference between the two profiles. Semaglutide has demonstrated cardiovascular benefit in people with established cardiovascular disease: the SELECT trial showed a 20% reduction in major cardiovascular events (hazard ratio 0.80). For tirzepatide, the equivalent data (SURMOUNT-MMO) is expected in 2027. The HAS has made its future assessment conditional on those results.
European guidance (EASO, 2025) draws the same practical line: both molecules recommended first-line for substantial weight loss, with semaglutide preferred when cardiovascular disease is established or with knee osteoarthritis, and tirzepatide put forward in obstructive sleep apnea.
Side effects: very close, two nuances
In SURMOUNT-5, with both drugs followed under the same conditions, digestive effects (the most common) were almost identical: nausea in about 44% of participants in each group, with comparable constipation and diarrhea. Two measured nuances:
- Vomiting: 21.3% on semaglutide vs 15.0% on tirzepatide.
- Injection-site reactions: 8.6% on tirzepatide vs 0.3% on semaglutide (redness, itching; overwhelmingly benign).
For both drugs, these effects cluster during dose escalation and ease over time. Our dedicated guide covers what to expect week by week.
In France: same rules, different amounts
Since 15 June 2026, both drugs have been reimbursed under strictly identical conditions (ministerial orders of 10 June 2026): initial BMI ≥ 40, or ≥ 35 with a listed comorbidity, documented failure of a six-month nutritional support program first, initial prescription by an authorized specialist, and a form to present at the pharmacy. Our coverage guide for residents of France walks through it.
The difference is the amounts, because prices scale with dose:
| Wegovy® | Mounjaro® | |
|---|---|---|
| Doses (1 weekly injection) | 0.25 → 2.4 mg | 2.5 → 15 mg |
| Public price per month | €146.91 → €195.10 | €176.10 → €433.80 |
| Out-of-pocket (35%) at maintenance dose | ≈ €68/month (2.4 mg) | ≈ €83–152/month (5–15 mg) |
Same mechanics for both: 65% covered by France’s national health insurance, the rest usually picked up by a standard (“responsable”) mutuelle plan, and up to 100% under the ALD scheme (obesity alone does not qualify).
📱 Whichever drug you and your doctor choose, the tracking is the same: your injections, your weight, your % lost. The Doza app keeps that journal in a few seconds a week, and your measurements and doses never leave your iPhone. Discover Doza →
Can you switch from one to the other?
It is done in practice, but there is no official conversion protocol: neither SmPC provides a dose equivalence or a switching schedule between the two molecules. The documented approach is cautious: restart at the new drug’s lowest dose and titrate back up under medical supervision. That is your doctor’s call, never a dose-for-dose swap.
So which one?
There is no universal answer; that is precisely the official French position. Useful questions to bring to your appointment:
- Do I have established cardiovascular disease? → semaglutide’s proven benefit weighs in.
- Sleep apnea? → tirzepatide has dedicated data.
- What monthly out-of-pocket can I absorb? → the gap can exceed €80/month at the top dose.
- How do I tolerate dose escalation? → both titration ladders can be adjusted; individual tolerance is unpredictable and reveals itself along the way.
📱 Walk into that appointment prepared: how long you have been on treatment, what dose, what weight, what trend. Doza keeps those numbers current for you. 14-day free trial on the annual plan. See how it works →
FAQ — Wegovy vs Mounjaro
Does Mounjaro really cause more weight loss than Wegovy?
In the only direct comparison (SURMOUNT-5), yes: −20.2% vs −13.7% on average over 72 weeks. But the trial was open-label, and France’s HAS considers it insufficient to declare superiority. Both drugs hold the same official rating in France.
Are Wegovy and Mounjaro covered the same way in France?
Yes, strictly: same BMI conditions, same pathway, same form, same 65% rate. Only the prices (hence the out-of-pocket) vary with the dose.
Which one has fewer side effects?
The profiles are very close (digestive effects dominate, mostly during dose escalation). Nuances from SURMOUNT-5: a bit more vomiting with semaglutide, more injection-site reactions with tirzepatide.
Which one if I have a heart condition?
Discuss it with your cardiologist: to date only semaglutide has demonstrated cardiovascular benefit (SELECT). Tirzepatide’s results are expected in 2027.
Can I switch between them?
Yes, but only as a medical decision: there is no official dose equivalence, and practice is to restart from the lowest dose of the new drug.
Is Ozempic an alternative for weight loss?
No: Ozempic® (semaglutide dosed for diabetes) is neither indicated nor covered for weight loss in France. Wegovy® is the weight-management version of semaglutide.
Sources: SURMOUNT-5, N Engl J Med 2025 (posted results: ClinicalTrials.gov NCT05822830) · HAS opinion on Mounjaro, 19 November 2025 · HAS Wegovy opinion CT-20916 (SELECT) · Wegovy SmPC and Mounjaro SmPC (EMA) · ministerial orders of 10 June 2026 · EASO statement, 2 October 2025 · prices: Vidal (12 June 2026). Last updated: 29 August 2026. Published by Doza (INFINI CONSULTING) — a French GLP-1 tracking app.