No trial has compared survodutide with retatrutide; in separate phase 3 trials, retatrutide cut 25.0% of body weight at 80 weeks and survodutide 13.0% at 76. Both were tested in people and neither is approved as of October 2026.
Retatrutide lost more weight in its own trials: 25.0% at 80 weeks in its largest phase 3 trial against 13.0% at 76 weeks for survodutide, counting everyone randomized in both. The trials differed in length and placebo result, and no trial has given both drugs. Survodutide has more liver evidence: a biopsy trial in people with fatty liver inflammation and scarring, and FDA Breakthrough Therapy designation for that disease. Retatrutide's liver data so far are MRI scans of liver fat in 98 people.
Every claim on this page is labeled by what was tested: in people, in animals or cells, or a regulatory fact. How we grade evidence: editorial policy.
| Item | Survodutide | Retatrutide |
|---|---|---|
| What it is | Weekly injection that switches on two receptors: glucagon and GLP-1 | Weekly injection that switches on three receptors: GIP, GLP-1 and glucagon |
| Made by | Boehringer Ingelheim, licensed from Zealand Pharma | Eli Lilly |
| Evidence label | Tested in people: three published phase 3 trials | Tested in people: two published phase 3 trials |
| FDA status | Investigational, not approved; Breakthrough Therapy designation for MASH (2024) | Investigational, not approved; Lilly plans to file in early 2027 |
| WADA 2026 | Not named; covered by S0, banned at all times | Not named; covered by S0, banned at all times |
| Last checked | October 17, 2026 | October 17, 2026 |
New trials, FDA changes and side-effect reports, written in plain English. Every result says whether it was tested in people or in animals.
Each row names its evidence type. Every study named here is linked in the sources list at the bottom of the page.
| Survodutide | Retatrutide | Evidence type | |
|---|---|---|---|
| Largest weight trial without diabetes | SYNCHRONIZE-1: 725 adults, 76 weeks. Weight fell 12.2% and 13.0% on the two doses vs 5.4% on placebo | TRIUMPH-1: 2,339 adults, 80 weeks. Weight fell 17.6%, 23.7% and 25.0% on the three doses vs 3.9% on placebo | Tested in people |
| Weight loss with type 2 diabetes | SYNCHRONIZE-2: 752 adults, 76 weeks. 8.2% and 9.8% vs 3.9% on placebo | TRIUMPH-2: 1,152 adults, 80 weeks. 11.9%, 16.8% and 18.8% vs 5.1% on placebo | Tested in people |
| Phase 2 weight result | 387 adults, 46 weeks: up to 14.9% vs 2.8% on placebo; 60% of all participants finished | 338 adults, 48 weeks: up to 24.2% vs 2.1% on placebo | Tested in people |
| Fatty liver | Biopsy trial of 293 adults with MASH and scarring: inflammation cleared without worse scarring in 43% to 62% vs 14% on placebo | MRI substudy of 98 adults: liver fat fell 82.4% at 24 weeks in the highest dose group vs a 0.3% rise on placebo; no biopsy trial reported | Tested in people |
| Blood sugar in type 2 diabetes | HbA1c fell 0.8 to 0.9 points vs 0.2 on placebo over 76 weeks (SYNCHRONIZE-2) | HbA1c fell up to 2.0 points vs no change on placebo over 24 weeks (phase 2, 281 adults) | Tested in people |
| Against an approved drug | At its higher doses, lost more weight than open-label semaglutide over 16 weeks in a 413-person diabetes trial | At all but its lowest dose, beat dulaglutide on weight in a 281-person diabetes trial; a trial against tirzepatide is still running | Tested in people |
| Stomach side effects | GI events in 80.9% and 89.7% vs 47.9% on placebo (SYNCHRONIZE-1) | Diarrhea in 27% to 34% and nausea in 14% to 28% vs 13% and 8% on placebo (TRIUMPH-2) | Tested in people |
| Other side effects to watch | 7.5% stopped for heart or blood vessel events in an 80-person phase 1 study with fast dose increases | Burning or tingling skin in 4% to 7% vs 1%, and low blood pressure in 1% to 6% vs under 1% (TRIUMPH-2); heart rate rose with dose in phase 2 | Tested in people |
| Heart safety data | SYNCHRONIZE-CVOT, 5,531 people, finished in June 2026; no results posted | TRIUMPH-Outcomes, about 10,000 people, still running; due to finish in 2029 | Regulatory fact |
| US status, October 2026 | Not approved. FDA has warned companies selling research-labeled survodutide | Not approved. FDA states it cannot be used in compounding under federal law | Regulatory fact |
Survodutide switches on two hormone receptors, glucagon and GLP-1. Retatrutide switches on those two plus a third, GIP. Both are weekly injections still in trials.
Survodutide is made by Boehringer Ingelheim under license from Zealand Pharma. In its first human studies, blood amino acid and glucagon levels fell, which the researchers read as the drug acting on both of its receptors (tested in people: two phase 1 studies, 149 people).
Retatrutide is made by Eli Lilly. It adds a third receptor, GIP, to the same GLP-1 and glucagon pair. Its half-life in a 72-person phase 1 trial was about 6 days, which is why it is given once a week (tested in people).
Retatrutide's trials reported more weight loss, but no trial has given both drugs. In people without diabetes it beat placebo by 21.0 percentage points at its highest dose, against 7.6 for survodutide's highest dose.
In TRIUMPH-1, 2,339 adults with obesity and no diabetes lost 25.0% of their weight over 80 weeks on retatrutide's highest dose, against 3.9% on placebo (Jastreboff, 2026). In SYNCHRONIZE-1, 725 adults with obesity and no diabetes lost 13.0% over 76 weeks on survodutide's highest dose, against 5.4% on placebo (le Roux, 2026). Both figures count everyone randomized, including people who stopped the drug (tested in people).
The gap holds in type 2 diabetes: 18.8% against 5.1% on placebo for retatrutide at 80 weeks (TRIUMPH-2, 1,152 adults), and 9.8% against 3.9% for survodutide at 76 weeks (SYNCHRONIZE-2, 752 adults). These are separate trials with different lengths, sites and placebo results, so the numbers are not a head-to-head test.
Patients. Tested in people. Every trial shown had a placebo group. Retatrutide's TRIUMPH-3 (1,949 people) and survodutide's heart safety trial (5,531) are left out because neither is published yet.
Survodutide has the stronger evidence: it is the only one of the two tested with liver biopsies. Retatrutide has cut liver fat on MRI but has no published biopsy result.
In a 48-week phase 2 trial of 293 adults with MASH (fatty liver with inflammation) and liver scarring, the inflammation cleared without the scarring getting worse in 43% to 62% of people on survodutide, against 14% on placebo (Sanyal, 2024). FDA gave survodutide Breakthrough Therapy designation for MASH with moderate or advanced scarring in October 2024. Two phase 3 trials, LIVERAGE and LIVERAGE-Cirrhosis, are recruiting (tested in people; regulatory fact).
In SYNCHRONIZE-MASLD, 216 adults with obesity and fatty liver, 84.2% on survodutide cut their liver fat by at least 30% over 48 weeks, against 24.3% on placebo, counting people who stayed on treatment (Kaplan, 2026; tested in people).
Retatrutide's liver evidence is a substudy of 98 adults from its phase 2 obesity trial. Liver fat measured by MRI fell 82.4% at 24 weeks in the highest dose group and rose 0.3% on placebo, and 86% of that group reached a normal liver fat level (Sanyal, 2024; tested in people). Lilly's liver outcomes trial, SYNERGY-Outcomes, is recruiting.
Both cause the stomach side effects of the GLP-1 class, mostly mild to moderate. Retatrutide's TRIUMPH-2 trial also reported burning or tingling skin and low blood pressure. In survodutide's first multi-dose study, some people stopped for heart or blood vessel events.
Survodutide: stomach side effects hit 80.9% and 89.7% of people on the two doses in SYNCHRONIZE-1, against 47.9% on placebo. In the phase 2 liver trial, nausea affected 66% against 23% on placebo, and vomiting 41% against 4%. In an 80-person phase 1 study that raised the dose quickly, 7.5% stopped for heart or blood vessel events (tested in people).
Retatrutide: in TRIUMPH-2, diarrhea affected 27% to 34% and nausea 14% to 28%, against 13% and 8% on placebo. Burning or tingling skin (dysesthesia) affected 4% to 7% against 1%, and low blood pressure up to 6% against under 1%. In the phase 2 obesity trial, heart rate rose with dose, peaked at 24 weeks and then came down (tested in people).
Neither is approved by FDA as of October 2026. Lilly plans to file retatrutide with FDA in early 2027. Both are banned in sport under WADA's S0 rule.
Every peptide's FDA, compounding and WADA status in one place: are peptides legal in the US.
These are the questions the published studies of both drugs leave open.
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