Retatrutide vs Semaglutide: Trials, Status, Half-Life
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[GLP-1 · Comparison]

Retatrutide vs semaglutide: how do they compare?

Mechanism · Trial results · Approval status · Half-life

Short answer: Semaglutide (Ozempic, Wegovy) is FDA approved and acts on the GLP-1 receptor. Retatrutide also acts on GIP and glucagon receptors and is not approved; Lilly plans to file in Q1 2027.1 No head-to-head results are published. One such trial, TRANSCEND-T2D-2 in type 2 diabetes, finished its primary phase in August 2026.2

Until TRANSCEND-T2D-2 reports, every retatrutide and semaglutide number on this page comes from a different trial, with different people, durations and ways of counting dropouts. They are not a direct comparison. For retatrutide against tirzepatide, see Retatrutide vs tirzepatide: how do they compare?.

How do retatrutide and semaglutide compare side by side?

Semaglutide from the US labels; retatrutide from published trials and Lilly releases. Checked October 2026.
RetatrutideSemaglutide (Ozempic, Wegovy)
MechanismGIP, GLP-1 and glucagon receptor agonist (triple agonist)3GLP-1 receptor agonist4
Approval statusInvestigational, not FDA approved; BLA planned Q1 20271FDA approved: Ozempic (type 2 diabetes), Wegovy (weight management; injection and tablets)4
Dosing scheduleStudied: start 2 mg weekly, stepped up every 4 weeks to 4, 9 or 12 mg in phase 35Wegovy label: 0.25 mg weekly for 4 weeks, then 0.5, 1 and 1.7 mg at 4-week steps; maintenance 1.7 or 2.4 mg, up to 7.2 mg4
Half-lifeabout 6 days (phase 1b)6about 7 days (label: about 1 week)7
Time to peak (Tmax)Not confirmed in a published sourceabout 2 days (label: 1 to 3 days)7
Dosing frequencyOnce weekly in trialsOnce weekly (Wegovy tablets: once daily)
FormsNo approved product; injected in trialsPens (Ozempic, Wegovy) and tablets (Wegovy)4
Head-to-head trialTRANSCEND-T2D-2 (about 1,250 adults with type 2 diabetes, open label, 80-week HbA1c endpoint); no results posted2Same trial; semaglutide is the comparator
Notable warningsNo label yet. In TRIUMPH-1, 11.3% stopped 12 mg for side effects vs 4.9% on placebo8Boxed thyroid C-cell tumor warning; pancreatitis, gallbladder disease, kidney injury, diabetic retinopathy complications4

Reviewed . Half-life figures are shown only where the value Dose Track uses agrees with the cited source.

Has retatrutide been tested against semaglutide?

Yes, but the results are not out. TRANSCEND-T2D-2 is a phase 3, open-label trial that randomizes adults with type 2 diabetes on metformin (with or without an SGLT2 inhibitor) to one of two retatrutide doses or weekly semaglutide. Its primary endpoint is the change in HbA1c at week 80. ClinicalTrials.gov lists the primary completion date as August 27, 2026, and shows no posted results.2

That trial is about blood sugar in type 2 diabetes. There is no registered or published head-to-head obesity trial of retatrutide against semaglutide on this page's sources.

What did each drug do in its own trials?

  • Retatrutide, TRIUMPH-1 (adults with obesity, no diabetes, 80 weeks): −17.6%, −23.7% and −25.0% on 4, 9 and 12 mg vs −3.9% on placebo, counting everyone randomized (treatment-regimen estimand).9 Lilly's efficacy estimand gives −19.0%, −25.9% and −28.3%.8
  • Retatrutide, phase 2 (338 adults, 48 weeks): −24.2% on 12 mg vs −2.1% on placebo.3
  • Semaglutide 2.4 mg, SURMOUNT-5 (adults with obesity, no diabetes, 72 weeks): −13.7%, as the comparator arm against tirzepatide.10
  • Semaglutide 2.4 mg, REDEFINE 1 (adults without diabetes, 68 weeks): −14.9% counting everyone randomized, −16.1% if everyone stayed on treatment.11

The retatrutide numbers are larger, but the trials differ in length, population and estimand. Only a randomized trial of both drugs in the same people can say how big the real gap is.

What does the extra glucagon receptor do?

Semaglutide acts on one receptor, GLP-1. Retatrutide acts on GLP-1, GIP and glucagon receptors.3 Both are weekly injections with long half-lives (about 6 days for retatrutide in phase 1b, about a week for semaglutide), so levels build over the first weeks of each dose.67 Retatrutide has no FDA label yet, so its approved dose range, warnings and interactions are not known.

This page summarizes labels and published studies. It is not personalized medical advice; confirm any dose or change with your prescriber.
Retatrutide vs tirzepatide: how do they compare?Triple vs dual agonist, TRIUMPH results, status Semaglutide vs tirzepatide: what did the head-to-head trial show?SURMOUNT-5 results, label titration, half-life CagriSema vs semaglutide: what does adding cagrilintide do?REDEFINE 1 semaglutide arm, REIMAGINE 2, FDA status

Frequently asked questions

Is retatrutide stronger than semaglutide?+
No published trial has compared them directly. In separate trials, retatrutide 12 mg gave −25.0% average weight change at 80 weeks (TRIUMPH-1, counting everyone randomized) and semaglutide 2.4 mg gave −13.7% at 72 weeks (SURMOUNT-5). Different trials make this a rough picture, not a verdict.910
Is there a retatrutide vs semaglutide trial?+
Yes. TRANSCEND-T2D-2 compares two retatrutide doses with weekly semaglutide in adults with type 2 diabetes, with HbA1c at week 80 as the main result. As of October 2026 no results are posted.2
What doses of retatrutide were studied?+
Phase 3 trials started at 2 mg weekly and stepped up every 4 weeks to 4, 9 or 12 mg. These are trial doses, not personalized advice; confirm any dose with your prescriber.5
Which has the longer half-life?+
Semaglutide, slightly: about 1 week per the Ozempic label, versus about 6 days for retatrutide in a phase 1b trial.76
Can I track retatrutide and semaglutide in Dose Track?+
Yes. Both are built in, with their half-lives, so you can log each shot and see estimated levels on one chart.

Sources

  1. Eli Lilly. Retatrutide successful in two additional phase 3 trials (TRIUMPH-2, TRIUMPH-3); BLA planned Q1 2027. Press release, July 23, 2026.
  2. TRANSCEND-T2D-2: retatrutide vs semaglutide in type 2 diabetes, phase 3 trial record (NCT06260722). ClinicalTrials.gov, updated September 2026.
  3. Jastreboff AM, et al. Triple-hormone-receptor agonist retatrutide for obesity: a phase 2 trial. N Engl J Med. 2023;389:514-526.
  4. Wegovy (semaglutide) injection and tablets prescribing information. DailyMed, revised June 2026.
  5. Eli Lilly. Retatrutide TRIUMPH-1 detailed results and dose-escalation scheme. Press release, June 6, 2026.
  6. Urva S, et al. LY3437943 (retatrutide) in people with type 2 diabetes: a phase 1b multiple-ascending dose trial. Lancet. 2022.
  7. Ozempic (semaglutide) injection prescribing information. DailyMed, revised June 2026.
  8. Eli Lilly. Retatrutide delivered powerful weight loss in pivotal phase 3 obesity trial (TRIUMPH-1). Press release, May 21, 2026.
  9. Retatrutide TRIUMPH-1 phase 3 obesity trial. N Engl J Med. Published online September 29, 2026.
  10. Aronne LJ, et al. Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5). N Engl J Med. 2025;393:26-36.
  11. Novo Nordisk. CagriSema demonstrates superior weight loss in adults with obesity or overweight in the REDEFINE 1 trial. Company announcement No 99/2024 (Form 6-K), December 20, 2024.

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