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Retatrutide vs Survodutide

Part of Weight Loss Drug Comparison Index.

Retatrutide vs Survodutide: Triple Agonist vs Dual Agonist

Retatrutide and survodutide are both next-generation obesity drugs that share an unusual feature: glucagon receptor agonism. Neither semaglutide (Ozempic/Wegovy) nor tirzepatide (Mounjaro/Zepbound) targets the glucagon receptor. These two drugs do — and that shared element is what makes this comparison interesting.
The key difference is what else they target. Retatrutide is a triple agonist (GLP-1 + GIP + glucagon), developed by Eli Lilly. Survodutide is a dual agonist (GLP-1 + glucagon), developed by Boehringer Ingelheim and Zealand Pharma. Retatrutide includes GIP agonism on top of the two receptors survodutide targets.

Neither drug is FDA-approved. Both are in Phase 3 clinical trials. No head-to-head trial has compared them directly, and the Phase 2 and Phase 3 data discussed below come from different trials with different designs, populations, and durations.

Side-by-Side Comparison

RetatrutideSurvodutide
MechanismGLP-1 + GIP + Glucagon (triple agonist)GLP-1 + Glucagon (dual agonist)
Development codeLY3437943BI 456906
ManufacturerEli LillyBoehringer Ingelheim / Zealand Pharma
FDA statusNot approved — Phase 3 (TRIUMPH program)Not approved — Phase 3 ongoing
DosingOnce weekly injectionOnce weekly injection
Selected trial dose12 mg6 mg in SYNCHRONIZE-1
Max weight loss (Phase 2)-24.2% at 48 weeks-14.9% at 46 weeks
Selected weight loss (Phase 3)-28.7% at 68 weeks (TRIUMPH-4)Up to -16.6% at 76 weeks (SYNCHRONIZE-1, efficacy estimand)
Glucagon agonismYesYes
GIP agonismYesNo
MASH/MASLD studiesYes (including SYNERGY-Outcomes)Yes (LIVERAGE program)
AvailabilityClinical trials onlyClinical trials only

How the Mechanisms Differ

Glucagon receptor activation is being studied for effects on energy expenditure and hepatic fat metabolism. Preclinical studies support this rationale, but the human trials do not isolate how much weight loss each receptor contributes. Counting receptor targets cannot establish which drug is better.

Survodutide: GLP-1 + Glucagon

Survodutide combines GLP-1 agonism (the same mechanism behind Ozempic and Wegovy) with glucagon agonism. The GLP-1 component reduces appetite, slows gastric emptying, and improves insulin secretion. The glucagon component increases energy expenditure and promotes fat breakdown, particularly in the liver.

This dual approach is similar to mazdutide (developed by Innovent Biologics), which also targets GLP-1 and glucagon. Survodutide does not include GIP agonism.

Retatrutide: GLP-1 + GIP + Glucagon

Retatrutide includes everything survodutide does — GLP-1 and glucagon agonism — and adds GIP (glucose-dependent insulinotropic polypeptide) as a third target. GIP further enhances insulin secretion and may have additional effects on fat metabolism. The inclusion of GIP is the same addition that differentiates tirzepatide from semaglutide, and it appears to contribute to greater overall weight loss.

Retatrutide includes GIP receptor activity; survodutide does not. A receptor list alone cannot quantify a difference in human weight loss or safety.

For a deeper explanation of each receptor, see What Is Retatrutide (GLP-3)?.

Weight Loss Comparison

Phase 2 Results

Both drugs have published Phase 2 weight loss data, but the trial designs differ in ways that matter.

Swipe sideways to see every column.

DrugTrialDurationParticipantsMax Weight Loss (ITT)
Retatrutide 12 mgPhase 2 (NEJM, NCT04881760)48 weeks338-24.2%
Survodutide 4.8 mgPhase 2 (Lancet Diabetes Endocrinol, NCT04667377)46 weeks386-14.9%

Survodutide Phase 2 Results by Dose

DoseWeight Loss (%)
0.6 mg-6.2%
2.4 mg-12.5%
3.6 mg-13.2%
4.8 mg-14.9%
Placebo-2.8%
In the survodutide trial, participants who completed the full treatment course on the 4.8 mg dose (the "actual treatment" analysis) achieved nearly -19% weight loss — and weight loss had not plateaued at 46 weeks, suggesting the final ceiling may be higher with longer treatment or higher doses. Up to 40% of participants on the highest doses achieved 20% or more weight loss.

Retatrutide Phase 3 Results

Retatrutide 12 mg produced 28.7% weight loss at 68 weeks under the TRIUMPH-4 efficacy estimand in adults with obesity or overweight and knee osteoarthritis without diabetes.
Survodutide now has Phase 3 results too. SYNCHRONIZE-1 studied 725 adults with overweight or obesity without diabetes for 76 weeks. The manufacturer reported up to 16.6% weight loss, versus 3.2% with placebo, under the efficacy estimand with 3.6 mg and 6 mg doses. These are separate trials, not a direct comparison.

Why These Numbers Are Not Directly Comparable

This comparison comes with significant caveats:

  • Different trial designs: The survodutide Phase 2 trial used a 20-week dose escalation followed by 26 weeks of maintenance. The retatrutide Phase 2 trial used a different titration schedule.
  • Different populations: Both trials enrolled adults with BMI of 27 or higher, but exclusion criteria, baseline characteristics, and comorbidity profiles differed.
  • Different durations: 46 weeks (survodutide) vs 48 weeks (retatrutide Phase 2) vs 68 weeks (retatrutide Phase 3).
  • Different trial phases: Both now have Phase 3 results; neither drug is FDA-approved.
  • No head-to-head trial: The only reliable way to compare two drugs is in a randomized controlled trial where participants are assigned to each drug under identical conditions. That trial does not exist for these two drugs.

Numerically different trial averages do not establish that adding GIP caused the difference. A direct trial would need to account for dose, population, follow-up, and tolerability.

Tolerability and Discontinuation

Both drugs produce gastrointestinal side effects common to the GLP-1 agonist class: nausea, vomiting, diarrhea, and constipation. However, the survodutide Phase 2 trial had a notably higher discontinuation rate.

Retatrutide (Phase 2)Survodutide (Phase 2)
Common side effectsNausea, diarrhea, vomiting, constipationNausea, diarrhea, vomiting, constipation
Discontinuation due to AEsLower (varied by dose)24.6% (vs 3.9% placebo)
Notable signalDysesthesia (tingling/burning)GI events during rapid dose escalation
The survodutide trial's 24.6% discontinuation rate due to adverse events is high compared to both retatrutide's Phase 2 data and the broader incretin drug class. However, context matters: the survodutide trial used a relatively rapid dose escalation over 20 weeks, which likely contributed to GI intolerance. Slower dose titration in Phase 3 trials may improve this number.
Dysesthesia (altered skin sensation) occurred in 8.8% and 20.9% of the retatrutide 9 mg and 12 mg groups in TRIUMPH-4. It is not unique to retatrutide: current Wegovy and Zepbound labels also report it. A glucagon-specific cause has not been established.
For more on retatrutide's safety profile, see Side Effects & Safety.

Liver Fat and MASH

Both drugs are being studied for metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH) and metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD). This is one of the most promising areas for glucagon-containing agonists.

Glucagon receptor activation directly promotes fat oxidation in the liver, reducing both fat accumulation and inflammation. This makes both survodutide and retatrutide strong candidates for liver disease — a therapeutic area where current treatment options are extremely limited.

The retatrutide Phase 2 liver substudy included 98 participants with baseline liver fat of at least 10%. At 12 mg, relative liver fat reduction was 82.4% at 24 weeks and 86.0% at 48 weeks. MRI-measured fat reduction does not establish MASH resolution, fibrosis improvement, or superiority over another drug. Retatrutide is included in SYNERGY-Outcomes.
Survodutide is also being actively studied in MASH/MASLD, with dedicated trials underway. Published Phase 2 data has demonstrated significant liver fat reductions, and the Boehringer Ingelheim MASH program is a major part of survodutide's development strategy.

The shared glucagon mechanism makes both drugs potentially important for liver disease, regardless of which produces more weight loss overall.

Development Status

MilestoneRetatrutideSurvodutide
Phase 1CompletedCompleted
Phase 2Completed (published 2023)Completed (published 2024)
Phase 3Ongoing (TRIUMPH program, 5+ trials)Ongoing
First Phase 3 readoutTRIUMPH-4 (December 2025)SYNCHRONIZE-1 (April 2026)
Expected FDA filingBLA planned Q1 2027TBD
Expected approvalNot establishedNot established
Lilly plans a US biologics license application in the first quarter of 2027. That is a filing target, not an FDA approval or launch date. Survodutide has reported SYNCHRONIZE-1 Phase 3 results and continues its obesity and liver-disease programs. Neither has an approved launch date.
For retatrutide's full regulatory timeline, see FDA Approval Timeline.

Frequently Asked Questions

Is retatrutide better than survodutide?

No direct trial establishes that. TRIUMPH-4 reported 28.7% with retatrutide 12 mg at 68 weeks; SYNCHRONIZE-1 reported up to 16.6% with survodutide at 76 weeks, both under efficacy estimands. Differences in population, protocol, safety, and follow-up prevent reading this as a treatment ranking.

Why do both drugs include glucagon?

Glucagon receptor activation is being studied for effects on energy expenditure and hepatic fat metabolism. Preclinical studies support this rationale, but the human trials do not isolate how much weight loss each receptor contributes. Counting receptor targets cannot establish which drug is better.

What does survodutide have that retatrutide does not?

Survodutide targets GLP-1 and glucagon receptors; retatrutide targets those two plus GIP. They are different molecules with distinct pharmacology and clinical programs. Fewer receptor targets does not establish worse efficacy or safety, and there is no direct trial between them.

Will either drug be available soon?

Neither is FDA-approved. Lilly plans a US biologics license application in the first quarter of 2027. That is a filing target, not an FDA approval or launch date. Survodutide has no established US approval date. Clinical trial eligibility and recruitment are separate from routine prescription access.

How do these drugs compare to Ozempic and Mounjaro?

Ozempic and Mounjaro are approved diabetes brands; Wegovy and Zepbound are the corresponding semaglutide and tirzepatide obesity brands. Retatrutide and survodutide remain investigational. Separate obesity trials cannot establish superior treatment for a person taking a diabetes medicine. See the brand comparison.

Sources

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What this is
Educational information, not medical advice. It reports published research — it doesn’t recommend that you use, obtain, or supply anything.
Regulatory status
Retatrutide and similar peptides are investigational — not approved by the FDA or any regulator. Semaglutide and tirzepatide are prescription-only medicines, available only through a licensed prescriber.
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Do not make decisions about your health without consulting a qualified healthcare provider. For trial enrolment, see ClinicalTrials.gov. More on how we review.

Grounded in primary sources
NEJMThe LancetJAMAFDAClinicalTrials.gov

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