Retatrutide vs Survodutide: Two Glucagon-Arm Agonists, One With GIP
Retatrutide and survodutide both carry a glucagon arm. Survodutide (BI 456906, Boehringer Ingelheim and Zealand Pharma) pairs GLP-1 with glucagon; retatrutide adds GIP as a third arm. Separately reported results: retatrutide 24.2% at 48 weeks (Phase 2) and 25.0% at 80 weeks (TRIUMPH-1, NEJM 2026); survodutide 13.0% at 76 weeks on 6.0 mg (SYNCHRONIZE-1, NEJM 2026, treatment-regimen estimand). Survodutide’s distinguishing programme is liver disease. Neither is approved, no head-to-head results exist, and New-U does not sell survodutide.
No head-to-head results exist. Doses, populations and endpoints differ, and survodutide’s programme is built around liver outcomes as much as weight, so a weight figure alone says nothing about its liver endpoints. Research context; nothing here is medical or dosing guidance. Regulatory and trial status is as of September 2026.
At a glance
| Retatrutide | Survodutide | |
|---|---|---|
| Receptor targets | GIP + GLP-1 + glucagon (triple) | GLP-1 + glucagon (dual) |
| Developer | Eli Lilly (LY3437943) | Boehringer Ingelheim / Zealand Pharma (BI 456906) |
| Cadence | Once-weekly (trials) | Once-weekly |
| Headline weight data | 24.2% at 48 wk (Phase 2); 25.0% at 80 wk (TRIUMPH-1, 12 mg, NEJM 2026) | 12.2% (3.6 mg) and 13.0% (6.0 mg) at 76 wk vs 5.4% placebo (SYNCHRONIZE-1, NEJM 2026, treatment-regimen estimand) |
| Distinguishing programme | Obesity, type 2 diabetes and other conditions under study | Obesity and MASH (FDA Breakthrough Therapy designation) |
| Status | Phase 3 (TRIUMPH); no approval | Phase 3; no approval |
| Research access | GLP1-RC-RT (retatrutide reference) | Not sold: proprietary |
What the glucagon arm does
On its own, glucagon raises blood glucose. Paired with GLP-1 the glucose effect is intended to be offset, leaving the arms researchers care about: higher energy expenditure and mobilisation of fat from the liver. Both drugs rely on this logic. The difference is the third receptor. Retatrutide layers GIP on top, adding the incretin effects tirzepatide is known for; survodutide stays a focused GLP-1 and glucagon pairing aimed squarely at weight and liver.
Comparing the two is close to a controlled question about what a GIP arm adds to a GLP-1/glucagon design. That is exactly why the cross-trial numbers cannot answer it: the trials differ in more than the receptor list.
What the trials showed
- Retatrutide (Phase 2, NEJM 2023, n=338): 17.1% (4 mg), 22.8% (8 mg) and 24.2% (12 mg) at 48 weeks against 2.1% on placebo. In TRIUMPH-1 (N Engl J Med 2026; PMID 42814954), investigators reported 25.0% at 80 weeks on 12 mg, against 3.9% on placebo.
- Survodutide (SYNCHRONIZE-1, Phase 3, 76 weeks, adults with obesity or overweight without diabetes): both primary endpoints met. In the published trial (N Engl J Med 2026; PMID 42253238, n=725), mean weight reduction at week 76 was 12.2% (3.6 mg) and 13.0% (6.0 mg) against 5.4% on placebo, on the treatment-regimen estimand that is the paper’s primary analysis. Boehringer Ingelheim’s earlier topline announcement quoted up to 16.6% against 3.2% on an efficacy estimand, a different analysis that is not the published primary result.
The dose ladders, analysis populations and durations differ, so the two sets of figures describe two programmes, not the molecules.
The liver angle
Because glucagon-receptor agonism has been associated with reduced liver fat in trials, survodutide is developed for MASH (metabolic dysfunction-associated steatohepatitis, the fibrosing form of fatty liver disease) as well as obesity, and it holds an FDA Breakthrough Therapy designation for non-cirrhotic MASH with moderate-to-advanced fibrosis. A designation is intended to expedite development and review; it is not an approval. Retatrutide’s published trials also report hepatic measures, but the two programmes are organised differently, and the liver evidence for each should be read from its own primary publications.
Research access
Survodutide is a proprietary Boehringer Ingelheim / Zealand Pharma molecule and New-U does not sell it. The survodutide research guide covers the MASH programme.
Research takeaway
- Both drugs use a glucagon arm; retatrutide adds GIP, survodutide does not.
- Separately reported weight figures are not comparable across the two programmes.
- Survodutide’s programme centres on MASH as well as weight.
- Neither is approved, no head-to-head results exist, and the other compound is proprietary and not sold by New-U.
Primary sources
- New England Journal of Medicine — Triple–Hormone-Receptor Agonist Retatrutide for Obesity (Jastreboff et al., 2023)
- New England Journal of Medicine — Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity (Jastreboff et al., 2026; TRIUMPH-1)
- New England Journal of Medicine — Survodutide Once Weekly for the Treatment of Adults with Obesity (le Roux et al., 2026; SYNCHRONIZE-1; PMID 42253238)
- Boehringer Ingelheim — Results from the Phase III SYNCHRONIZE-1 obesity trial (sponsor topline, efficacy estimand)
Retatrutide as a research reference (GLP1-RC-RT)
New-U catalogues laboratory research material under GLP1-RC-RT (retatrutide reference). Survodutide is a proprietary Boehringer Ingelheim / Zealand Pharma molecule and is not sold. The trial results above describe the sponsors’ investigational products, not this material. Published Certificates of Analysis are available for the batches listed in the COA library. Research use only – all claims made on this site are for testing and research use only.
View GLP1-RC-RTFrequently asked questions
Is survodutide better than retatrutide?
No trial has compared them. Separately, survodutide reported 13.0% at 76 weeks on 6.0 mg (SYNCHRONIZE-1, NEJM 2026, treatment-regimen estimand) and retatrutide 24.2% at 48 weeks (Phase 2) and 25.0% at 80 weeks (TRIUMPH-1, NEJM 2026). Programmes and endpoints differ. Research context only.
What is the difference between retatrutide and survodutide?
Survodutide is a GLP-1 + glucagon dual agonist. Retatrutide adds GIP-receptor agonism as a third arm. Survodutide’s programme also emphasises MASH.
Is survodutide approved?
As of September 2026, no. The sources reviewed report no marketing authorisation. Its FDA Breakthrough Therapy designation for MASH is intended to expedite development and review but is not an approval.
How does the glucagon arm relate to glucose in the trials?
Glucagon-receptor agonism alone raises glucose. In both programmes it is paired with GLP-1 agonism, and each programme’s trials report glycaemic and liver measures; read those from the primary publications.
Can survodutide be bought as a research compound?
No. It is proprietary and New-U does not sell it.
External links are provided for research reference only; New-U is not affiliated with the cited organisations. All figures are published trial results shown for research context, not dosing guidance. New-U Research Compounds supplies research compounds strictly for laboratory research use only — not for human consumption.