The efficacy gap here is the widest in the category: 24.2% for retatrutide against 14.9% for semaglutide on published trials. A direct phase 3 comparison in 1,250 adults is enrolled and running. But Wegovy holds one thing no trial result transfers — an approved indication for reducing cardiovascular events, earned through a dedicated outcomes trial. For some readers that outweighs everything above.
Side by side
| Retatrutide | Wegovy | |
|---|---|---|
| Status | Investigational, phase 3 | FDA approved |
| Targets | GLP-1, GIP, glucagon | GLP-1 |
| Weight loss, obesity | 24.2% at 48 wks (phase 2, n=338) | 14.9% at 68 wks (n=1,961) |
| Weight loss, type 2 diabetes | 15.3% at 40 wks (phase 3) | ~9.6% at 68 wks |
| Nausea | Not quantified — no label | 44% |
| Stopped for side effects | 2–5% | ~7% |
| Cardiovascular indication | No — trial running | Yes, approved |
| Can you get it | No | Yes, by prescription |
| Maker | Eli Lilly | Novo Nordisk |
The efficacy gap, and how confident to be about it
Nine and a half percentage points separate 24.2% from 14.9% — on a 100 kg starting weight, roughly ten kilograms. It is a bigger gap than the one between semaglutide and tirzepatide, which was itself decisive when tested directly.
The tighter reading is again type 2 diabetes, where both have been studied and where every drug in this class performs worse:
| In type 2 diabetes | Weight loss | Duration |
|---|---|---|
| Retatrutide 12 mg | 15.3% | 40 weeks |
| Semaglutide 2.4 mg | ~9.6% | 68 weeks |
Retatrutide reached over half again as much weight loss in roughly half the time, in the same population. Different trials, so not proof — but two independent comparisons pointing the same way, one of them population-matched.
NCT06260722 will settle it: a phase 3 trial of retatrutide against semaglutide in 1,250 adults with type 2 diabetes, enrolled and running. Larger than the tirzepatide head-to-head, and not yet reported.
The thing Wegovy owns
Wegovy is approved to reduce the risk of major cardiovascular events — heart attack, stroke, cardiovascular death — in adults with cardiovascular disease and overweight or obesity. That indication came from a dedicated outcomes trial designed to measure those events over years, not from the weight-loss programme.
Retatrutide has no such indication. It has a 10,000-patient cardiovascular outcomes trial running, which is a serious commitment and the largest study in its programme, but it has not reported and cannot be assumed to be positive. Weight loss is not the same as cardiovascular protection: several older weight-loss drugs reduced weight and were withdrawn over cardiovascular harm.
Two facts sharpen this. Retatrutide's phase 2 recorded dose-dependent increases in heart rate peaking at 24 weeks, which is precisely the kind of finding a cardiovascular outcomes trial exists to interpret. And for a reader with established heart disease, a proven reduction in events is worth more than an unproven larger weight loss.
Tolerability
Retatrutide's phase 3 reported 2 to 5% discontinuing for adverse events against 0% on placebo; Wegovy's programme reports around 7%. Wegovy's label also quantifies what retatrutide's cannot: 44% nausea, 30% diarrhoea, 24% vomiting at the maintenance dose.
That 44% is the highest nausea figure among the approved weight drugs — above tirzepatide's 28% and Foundayo's 35%. So the comparison here is not "stronger drug, harsher drug". On the evidence available, retatrutide appears both more effective and better tolerated than semaglutide.
The caution stands: retatrutide's numbers come from 537 people over 40 weeks against a full approval programme, and no incidence table exists for it at all. See retatrutide side effects.
Availability decides most real cases
Wegovy can be prescribed today, at a known dose, from a pharmacy, with a manufacturer accountable for the vial. Retatrutide cannot, other than through a narrow compassionate use programme reported in 2026.
What is sold online under the name is not the drug in these trials in any usable sense: three such products analysed in Australia contained 51%, 165% and 190% of their labelled dose. Every figure on this page describes a measured dose administered under supervision. None of it transfers to a vial of unknown strength.
Which, and when
- Choosing treatment now: Wegovy, or another approved option — see the best GLP-1 for weight loss. Retatrutide is not a choice yet.
- Heart disease in the picture: Wegovy, and the argument is not close. A proven reduction in cardiovascular events beats an unproven larger weight loss.
- Which molecule is stronger: retatrutide, on everything published, pending the head-to-head.
- Which is better tolerated: retatrutide on the current evidence, from far less of it.
- Tracking what changes: the GLP-1 pipeline tracker.
The other comparisons
Wegovy is not the strongest approved option. Retatrutide vs Zepbound is the closer contest, and retatrutide vs Ozempic covers the diabetes population where the running head-to-head actually sits.
Scientific References
4 sources- 1
Jastreboff AM, Kaplan LM, Frías JP, et al.
Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial
New England Journal of Medicine · 389(6) · 2023PMID: 37366315
NEJM - 2
Bajaj HS, Welch M, Shah P, et al.
Efficacy and safety of retatrutide in people with type 2 diabetes (TRANSCEND-T2D-1): a phase 3 trial
The Lancet · 407(10546) · 2026PMID: 42250575
- 3
Wilding JPH, Batterham RL, Calanna S, et al.
Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP-1)
New England Journal of Medicine · 384(11) · 2021PMID: 33567185
NEJM - 4
U.S. National Library of Medicine
NCT06260722 — Effect of Retatrutide Compared With Semaglutide in Adult Participants With Type 2 Diabetes, phase 3, 1,250 participants; status read 13 August 2026
ClinicalTrials.gov · 2026
References open in a new tab. Content is reviewed against peer-reviewed literature as part of our editorial policy.
About the author
Editor, Modern Weight Science
Claudiu Gheorghe is the editor of Modern Weight Science. He is not a physician. His role is to synthesize peer-reviewed studies, clinical-trial data, and FDA prescribing information into clear, plain-language explanations, and to make sure every factual claim on the site traces back to a cited source. Any decision about starting, changing, or stopping a medication belongs with a licensed clinician who knows your history.
Every claim is checked against peer-reviewed research through our review process and fact-checking policy.
Frequently Asked Questions
Is retatrutide better than Wegovy?
On published trials, by a wide margin on weight: 24.2% against 14.9% in obesity, and 15.3% at 40 weeks against roughly 9.6% at 68 weeks in type 2 diabetes. These are separate trials, and a direct phase 3 comparison in 1,250 adults is running. But Wegovy has an approved cardiovascular indication that retatrutide has not been shown to match, and Wegovy can actually be prescribed.
Does retatrutide protect the heart like Wegovy?
Nobody knows. Wegovy is approved to reduce major cardiovascular events on the basis of a dedicated outcomes trial. Retatrutide has a 10,000-patient cardiovascular outcomes trial running — the largest study in its programme — but it has not reported. Weight loss is not the same as cardiovascular protection, and retatrutide's phase 2 recorded dose-dependent heart rate increases peaking at 24 weeks, which is part of what that trial exists to interpret.
When will retatrutide be compared directly with Wegovy?
NCT06260722 is a phase 3 trial of retatrutide against semaglutide in 1,250 adults with type 2 diabetes, enrolled and running. It is larger than the equivalent trial against tirzepatide. Until it reports, every comparison between these two drugs is cross-trial arithmetic.
Which has worse side effects, retatrutide or Wegovy?
Wegovy, on what is available. Its label reports 44% nausea at the maintenance dose — the highest among approved weight-loss drugs — and around 7% discontinuing for adverse events. Retatrutide's phase 3 reported 2 to 5% discontinuing against 0% on placebo. Retatrutide has no label and therefore no incidence percentages, and its data covers far fewer people over less time.
Should I wait for retatrutide instead of starting Wegovy?
That is a question for your clinician, but the timeline is worth knowing: retatrutide is in phase 3 with several large trials still active, including a 10,000-patient cardiovascular study, and there is no approval date. Waiting means waiting years, not months, with no result in the meantime — while Wegovy produces roughly 14.9% mean weight loss and carries a proven cardiovascular benefit today.
Continue learning
Where to read next
Not medical advice. This guide is for general education only. GLP-1 medications, dosing, and treatment suitability are decisions for you and a licensed clinician who knows your full medical history.