Survodutide: Phase 3 Weight Loss Data and Status
The short answer
Survodutide is an investigational once-weekly glucagon and GLP-1 receptor dual agonist from Boehringer Ingelheim. It is not FDA approved. In the 76-week SYNCHRONIZE-1 trial, adults without diabetes lost 12.2% on 3.6 mg and 13.0% on 6.0 mg, against 5.4% on placebo. Gastrointestinal side effects were the most common.
Survodutide (also written BI 456906) is an investigational once-weekly injection that activates two receptors: the GLP-1 receptor, the target of semaglutide, and the glucagon receptor. It is being developed by Boehringer Ingelheim for obesity and for metabolic dysfunction-associated steatotic liver disease (MASLD). Phase 3 results appeared in 2026. This page reads those papers, says plainly what is and is not known, and covers the legal position. It is a research reference, not a recommendation to use anything.
Survodutide at a glance
| What | Where it stands |
|---|---|
| Type | Dual glucagon receptor and GLP-1 receptor agonist, given by subcutaneous injection once weekly (Contemporary Clinical Trials review, 2026) |
| Developer | Boehringer Ingelheim (funder of the SYNCHRONIZE trials) |
| Approval status | Investigational. Not FDA approved for any use at the time of our check on 6 November 2026 |
| Phase 3 doses | Adjusted up to 3.6 mg or 6.0 mg once weekly; no approved dose schedule exists |
| Phase 3 duration | 76 weeks |
| Main phase 3 trials | SYNCHRONIZE-1 (obesity, no diabetes), SYNCHRONIZE-2 (obesity with type 2 diabetes), SYNCHRONIZE-MASLD (obesity with liver disease), plus regional trials in China and Japan |
How glucagon adds to GLP-1
GLP-1 receptor agonism lowers appetite and slows gastric emptying. The 2026 review of the evidence describes glucagon receptor agonism as adding effects on energy expenditure and on how the liver handles fat. That is the reasoning behind a liver trial running alongside the obesity trials. The same review is clear that comparative effectiveness, durability, long-term safety and what happens after stopping are still to be established (review).
What the phase 3 trials found
| Outcome at week 76 | Survodutide 3.6 mg | Survodutide 6.0 mg | Placebo |
|---|---|---|---|
| SYNCHRONIZE-1, obesity without diabetes, 725 adults (NEJM 2026): mean weight change | -12.2% (95% CI -13.6 to -10.8) | -13.0% (95% CI -14.4 to -11.6) | -5.4% (95% CI -6.9 to -4.0) |
| SYNCHRONIZE-1: weight loss of at least 5% | 72.6% | 71.9% | 46.3% |
| SYNCHRONIZE-1: any gastrointestinal event | 80.9% | 89.7% | 47.9% |
| SYNCHRONIZE-2, obesity with type 2 diabetes, 752 adults (NEJM 2026): mean weight change | -8.2% (95% CI -9.2 to -7.2) | -9.8% (95% CI -10.8 to -8.8) | -3.9% (95% CI -4.9 to -2.9) |
| SYNCHRONIZE-2: weight loss of at least 5% | 57.6% | 64.5% | 35.1% |
| SYNCHRONIZE-2: HbA1c change (from 7.4%) | -0.9 points | -0.8 points | -0.2 points |
| SYNCHRONIZE-2: any gastrointestinal event | 72.8% | 77.7% | 38.6% |
Both trials were double blind, placebo controlled and funded by Boehringer Ingelheim. The gastrointestinal events were typically mild to moderate, and SYNCHRONIZE-1 reported no deaths. The headline numbers use the treatment-regimen estimand, which counts everyone randomised, including people who stopped early or took other weight-loss drugs. Analyses that count only people who stayed on treatment give larger figures, so check which estimand a quoted number uses before comparing it with anything else.
How it compares with approved drugs
There is no head-to-head trial of survodutide against another drug, so any ranking is a comparison across different trials in different populations. For context, the pivotal trial of semaglutide 2.4 mg (STEP 1) reported -14.9% at 68 weeks and tirzepatide (SURMOUNT-1) up to -20.9% at 72 weeks; the full tables are in Zepbound vs Wegovy. A 2026 phase 2 summary puts the earlier survodutide result at up to 18.7% at 46 weeks on 4.8 mg against 2.3% on placebo, against 12.2% to 13.0% at 76 weeks in the larger phase 3 trial. For a three-receptor drug see tirzepatide vs retatrutide; for another glucagon-containing dual agonist see mazdutide.
Safety points to know
Gastrointestinal effects were the most common problem in both trials and rose with dose. A 2026 review in the Journal of the American Heart Association found that survodutide and mazdutide raised heart rate to a similar extent as GLP-1 drugs alone. As with every GLP-1 receptor agonist on the market, thyroid C-cell tumors in rodents are the reason for the boxed warning on approved products; no human survodutide label exists yet to tell you what its warnings will say.
Legal status and "research" vials
Because survodutide is not approved, no pharmacy can fill a prescription for it and no dose or schedule is authorised. Vials sold online as survodutide "for research" are unapproved drugs. FDA has named survodutide in warning letters to sellers, including a letter to NuScience Peptides dated 24 August 2026 that also names mazdutide (FDA warning letter). The Bureau does not publish a dosing table or a calculator for survodutide for that reason: there is no approved, validated schedule to put in one. See the enforcement tracker and the research peptide legal status guide for how the market is being policed.
What to watch
The things that would change this page are a regulatory filing and decision, the remaining phase 3 readouts (including the liver-disease and regional trials), and any head-to-head trial. We will update the date and figures here when those land.
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Build your stack, 2 minutesFrequently asked questions
Is survodutide FDA approved?
No. At our check on 6 November 2026 survodutide was investigational, and the 2026 trial papers and reviews all describe it that way. FDA has named survodutide in warning letters to sellers of unapproved products labelled for research.
How much weight did people lose on survodutide?
In SYNCHRONIZE-1, adults with obesity and no diabetes lost a mean 12.2% on 3.6 mg and 13.0% on 6.0 mg at 76 weeks, against 5.4% on placebo (treatment-regimen estimand). In SYNCHRONIZE-2, adults with type 2 diabetes lost 8.2% and 9.8% against 3.9% on placebo.
What are the side effects of survodutide?
Gastrointestinal events were the most common: 80.9% on 3.6 mg and 89.7% on 6.0 mg in SYNCHRONIZE-1, against 47.9% on placebo, typically mild to moderate. A 2026 review found heart rate rose to a similar extent as with GLP-1 drugs alone.
Is survodutide better than tirzepatide or semaglutide?
No trial has compared them. Across separate trials, survodutide at 76 weeks (-12.2% to -13.0%) sits below the tirzepatide and semaglutide pivotal trial results, but the populations and designs differ, so this is context and not a ranking.
Sources (checked 6 November 2026)
- Survodutide Once Weekly for the Treatment of Adults with Obesity (SYNCHRONIZE-1), New England Journal of Medicine, 2026. Checked 6 November 2026.
- Survodutide Once Weekly in Adults with Obesity and Type 2 Diabetes (SYNCHRONIZE-2), New England Journal of Medicine, 2026. Checked 6 November 2026.
- Survodutide for the treatment of obesity: mechanistic rationale, clinical evidence, and remaining uncertainties, Contemporary Clinical Trials, 2026. Checked 6 November 2026.
- Heart rate effects of glucagon-containing dual agonists, Journal of the American Heart Association, 2026. Checked 6 November 2026.
- FDA warning letter to NuScience Peptides LLC, 24 August 2026. Checked 6 November 2026.
Trial figures are from the 2026 SYNCHRONIZE-1 and SYNCHRONIZE-2 publications. Survodutide is not approved anywhere we checked; nothing here is a dosing recommendation. Labels and trial records change; the leaflet in your box and your prescriber come first. Educational content, not medical advice.