Semaglutide vs retatrutide
Retatrutide acts on three receptors (GIP, GLP-1 and glucagon) and is not FDA-approved. Semaglutide, sold as Wegovy and Ozempic, acts on one (GLP-1) and is approved. In separate trials, weight change was −25.0% at 80 weeks on retatrutide 12 mg (TRIUMPH-1) and −14.9% at 68 weeks on semaglutide 2.4 mg (STEP 1). No head-to-head trial exists.[1,2]
5 sources, every number linked. PepDose sells no peptides and takes no vendor money.
At a glance
How do Semaglutide and Retatrutide compare?
No published trial has compared these directly. The numbers come from separate trials with different people and lengths, so treat the gap between them as a rough guide, not a measured difference.
| Semaglutide | Retatrutide | |
|---|---|---|
| Receptors | SemaglutideGLP-1 | RetatrutideGIP, GLP-1 and glucagon |
| FDA status[3,2] | SemaglutideApproved: Wegovy (2021), Ozempic | RetatrutideNot approved for any use |
| Developer | SemaglutideNovo Nordisk | RetatrutideEli Lilly |
| How often | SemaglutideOnce a week | RetatrutideOnce a week |
| Main obesity trial[1,2] | SemaglutideSTEP 1: 1,961 adults, 68 weeks | RetatrutideTRIUMPH-1: 2,339 adults, 80 weeks |
| Weight change on the top dose[1,2] | Semaglutide−14.9% on 2.4 mg (placebo −2.4%) | Retatrutide−25.0% on 12 mg (placebo −3.9%) |
| Stopped because of side effects[1,4] | SemaglutideSTEP 1: 4.5% for stomach side effects (placebo 0.8%) | RetatrutideTRIUMPH-2: 4% to 12% (placebo 5%) |
| Heart-outcome trial[5] | SemaglutideSELECT: 20% lower risk of heart attack, stroke or cardiovascular death | RetatrutideNone published |
Receptors
Which receptors does each one act on?
Tap a drug to compare. Each extra receptor adds another hormone signal. More receptors does not by itself mean safer or better.
What is the difference between semaglutide and retatrutide?
Semaglutide mimics a single gut hormone, GLP-1, and has been an approved medicine for years. Retatrutide activates three receptors (GIP, GLP-1 and glucagon) and is still investigational: its phase 3 results were published in September 2026 and it has no FDA approval.[3,2]
Does retatrutide cause more weight loss than semaglutide?
The separate trials point that way, but no trial has compared them. Average weight change was −25.0% over 80 weeks on retatrutide 12 mg (TRIUMPH-1) and −14.9% over 68 weeks on semaglutide 2.4 mg (STEP 1). Different participants and trial lengths mean this is not a measured difference.[2,1]
Which has the longer safety record?
Semaglutide. It has been FDA-approved for weight management since 2021 and was followed for about 40 months in the 17,604-person SELECT trial. Retatrutide's largest trials ran for 80 weeks and reported low blood pressure and unusual skin sensations more often than placebo, alongside stomach side effects.[3,5,4]
Work out the units for your vial
Milligrams are not comparable between compounds, and the units on your syringe depend on your vial and how much water you add. Each guide has a chart for its common vial sizes.
Questions
Common questions
Is retatrutide better than semaglutide?
It is not known. No trial has compared them. Retatrutide showed larger average weight change in its own trial (−25.0% at 80 weeks) than semaglutide did in its trial (−14.9% at 68 weeks), but it is unapproved and has a much shorter safety record.
Can you get retatrutide from a pharmacy like Wegovy?
No. Retatrutide is not FDA-approved, so there is no pharmacy version. Products sold online as retatrutide are unregulated research products.
Does retatrutide have heart-outcome data?
Not yet in published form. Semaglutide has SELECT, in which 2.4 mg cut the risk of heart attack, stroke or cardiovascular death by 20% over about 40 months.
Are the doses comparable?
No. Semaglutide's weight-management dose is 2.4 mg weekly; the TRIUMPH trials tested 4, 9 and 12 mg of retatrutide weekly. They are different molecules, so milligrams do not translate.
Sources
- 1.Once-weekly semaglutide in adults with overweight or obesity (STEP 1)
Wilding JPH et al. N Engl J Med 2021;384:989-1002 · Human trial - 2.Retatrutide, a triple hormone receptor agonist, for treatment of obesity (TRIUMPH-1)
Jastreboff AM et al. N Engl J Med 2026 (online Sep 29) · Human trial - 3.Wegovy approval letter
FDA. Wegovy (semaglutide) NDA 215256 approval letter, June 2021 · FDA - 4.Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2)
Bellido V et al. Lancet 2026 (online Sep 29) · Human trial - 5.Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT)
Lincoff AM et al. N Engl J Med 2023;389:2221-2232 · Human trial
Last reviewed Nov 7, 2026. Education only, not medical advice. PepDose sells no peptides.