Survodutide: what it is, SYNCHRONIZE trial results, side effects and approval status

Survodutide, developed under the code BI 456906, is a single synthetic peptide that acts on two receptors: the receptor for glucagon-like peptide-1 (GLP-1), the target of semaglutide and liraglutide, and the receptor for glucagon. Boehringer Ingelheim selected it as its clinical candidate from a set of 19 dual agonists on the basis of what its scientists described as balanced pharmacology: enough glucagon receptor activity to add weight loss beyond a GLP-1 drug, while keeping glucose-lowering comparable to a GLP-1 drug alone ^[1].

It is one of a group of investigational multi-receptor drugs that includes mazdutide, which has the same glucagon and GLP-1 receptor pairing and was approved in China in 2025, and retatrutide, which adds GIP receptor activity. Tirzepatide, a licensed GIP and GLP-1 agonist, does not act on the glucagon receptor. Survodutide is being studied for obesity, type 2 diabetes and metabolic dysfunction-associated steatohepatitis (MASH), the liver disease formerly called NASH ^{[5] [9]}.

The survodutide peptide is sold by online research suppliers because of these trial results. Those products are not the Boehringer Ingelheim trial drug and no licensed version exists. See what research peptides are for what the research label means in practice.

The GLP-1 component reduces appetite and food intake, slows stomach emptying and improves insulin secretion. The glucagon component is intended to raise energy expenditure and increase fat breakdown in the liver. In the first human study, in Japanese men with overweight or obesity, survodutide lowered plasma alanine and glucagon levels, which the investigators took as evidence that both receptors were being engaged, and paracetamol absorption tests showed transient delayed gastric emptying in the first week ^[2].

A 2026 study from Boehringer Ingelheim looked at where in the brain survodutide acts. Using a fluorescently labelled version in mice, the researchers found that it reaches the circumventricular organs, regions where the blood-brain barrier is weaker, and adjacent hypothalamic and hindbrain nuclei, without spreading uniformly across the brain. It activated multiple nuclei involved in food intake. A glucagon-only agonist did not activate those satiety regions or reduce food intake, although it did reduce body weight, which supports the idea that the appetite effect comes from the GLP-1 receptor and the extra weight effect from the glucagon receptor ^[11]. These are animal findings.

The liver is where the glucagon component is expected to matter most, which is why survodutide is being tested in MASH. In the phase 2 MASH trial, 63% to 67% of participants on survodutide had at least a 30% reduction in liver fat, against 14% on placebo ^[5].

The first published human data came from a phase 1 study in 36 Japanese men with a BMI of 23 to 40. Doses escalated over 16 weeks to 1.8 mg or 4.8 mg once weekly, or 2.4 mg twice weekly. Placebo-corrected weight loss was 5.57%, 12.37% and 9.62% respectively. Ten of the 27 men on survodutide withdrew from dose escalation because of adverse events, nine of them for decreased appetite, and the withdrawal rate was highest in the 4.8 mg group at 66.7% ^[2].

The phase 2 obesity trial enrolled 387 adults with a BMI of at least 27 and no diabetes at 43 centres in 12 countries. They received 0.6, 2.4, 3.6 or 4.8 mg weekly or placebo for 46 weeks, with 20 weeks of dose escalation and 26 weeks of maintenance. Analysed by planned treatment, weight fell by 6.2%, 12.5%, 13.2% and 14.9% on the four doses against 2.8% on placebo. Only 60% of participants completed the 46 weeks, and adverse events occurred in 91% of those on survodutide against 75% on placebo, mostly gastrointestinal ^[3]. These survodutide results are the main phase 2 evidence.

In type 2 diabetes, a 16-week phase 2 trial randomised 413 people on metformin to six survodutide regimens, placebo or open-label semaglutide up to 1.0 mg. HbA1c fell by 0.91 to 1.71 percentage points on survodutide, and the low 0.9 mg dose matched semaglutide (1.46 against 1.47). Weight fell by up to 8.7% on the highest twice-weekly regimen, and doses of 1.8 mg weekly or more produced more weight loss than semaglutide at 5.3%. Adverse events were reported by 77.8% on survodutide against 52.5% on placebo and 52.0% on semaglutide ^[4].

A phase 1 study in people with cirrhosis found that a single 0.3 mg dose produced similar drug exposure in people with and without liver impairment, so no dose adjustment appears to be needed for liver disease. A multiple-dose cohort that escalated to 6.0 mg over 24 weeks saw reductions in liver fat, liver stiffness and body weight, with drug-related adverse events in more than 80% of participants ^[6].

The SYNCHRONIZE programme is Boehringer Ingelheim’s phase 3 series. SYNCHRONIZE-1 enrolled 726 adults with obesity without diabetes and SYNCHRONIZE-2 enrolled 755 adults with obesity and type 2 diabetes; both randomised participants to survodutide escalated to 3.6 mg or 6.0 mg weekly or placebo for 76 weeks, with dose flexibility allowed ^[9]. A cardiovascular outcomes trial, SYNCHRONIZE-CVOT, was designed to enrol about 4,935 adults with a BMI of at least 27 and cardiovascular disease, kidney disease or risk factors, with major adverse cardiovascular events as the primary outcome ^[10]. The registry record shows that it enrolled 5,531 participants and is listed as completed with a primary completion date of June 2026 ^[14].

SYNCHRONIZE-1 was published in the New England Journal of Medicine in 2026. Among 725 participants with a mean BMI of 37.9 and mean weight of 108.8 kg, weight change at week 76 by the treatment-regimen estimand was −12.2% on 3.6 mg, −13.0% on 6.0 mg and −5.4% on placebo. The shares losing at least 5% were 72.6%, 71.9% and 46.3%. Gastrointestinal adverse events affected 80.9% of the 3.6 mg group, 89.7% of the 6.0 mg group and 47.9% on placebo. No deaths occurred ^[7]. Two features of this trial are worth noting: the placebo group lost more weight than in most obesity trials, and the analysis counted the effects of early discontinuation, prohibited weight-loss medicines and a prolonged escalation period, which tends to shrink the apparent drug effect compared with an analysis of people who stayed on treatment.

SYNCHRONIZE-MASLD, published in Nature Medicine in 2026, enrolled 216 adults with obesity and at-risk fatty liver disease in the United States and Spain and gave survodutide 6.0 mg or placebo for 48 weeks. Using the efficacy estimand, 84.2% on survodutide had at least a 30% reduction in liver fat against 24.3% on placebo, and weight fell by 12.2% against 1.0%. By the more conservative treatment-regimen estimand the figures were 68.5% against 28.6%, and −8.7% against −1.4% ^[8].

SYNCHRONIZE-2, in type 2 diabetes, is listed on ClinicalTrials.gov as completed in December 2025 ^[13], and its baseline characteristics were published in 2026 ^[12], but we found no results in a peer-reviewed journal or on the registry as of September 2026. A separate phase 3 trial in Chinese adults, SYNCHRONIZE-CN, has published its design ^[16]. A phase 3 trial in MASH with cirrhosis, LIVERAGE-Cirrhosis, is recruiting ^[19].

The MASH results are the part of the survodutide programme that most distinguishes it from GLP-1 drugs. In a 48-week phase 2 trial published in the New England Journal of Medicine in 2024, 293 adults with biopsy-confirmed MASH and fibrosis stage F1 to F3 received 2.4, 4.8 or 6.0 mg weekly or placebo. Improvement in MASH without worsening of fibrosis, the primary end point, occurred in 47%, 62% and 43% of the three survodutide groups against 14% on placebo. Fibrosis improved by at least one stage in 34% to 36% on survodutide against 22% on placebo. Nausea affected 66% on survodutide against 23% on placebo, diarrhoea 49% against 23% and vomiting 41% against 4% ^[5].

The dose-response was not linear: the middle dose, 4.8 mg, did best on the histology end point, which the authors attributed to the best-fitting quadratic model ^[5]. Whether the highest dose was held back by higher dropout or by something else is not clear from the abstract.

Every survodutide trial has used a long dose-escalation period: 16 weeks in the phase 1 study ^[2], 20 weeks in the phase 2 obesity trial ^[3], and 24 weeks in the MASH and cirrhosis studies ^{[5] [6]}. In the phase 2 obesity trial the 46-week result therefore reflects only 26 weeks at the target dose ^[3]. In the phase 1 study, the placebo-corrected weight loss of 12.37% at 16 weeks was reached during escalation ^[2].

The phase 3 trials measured results at 76 weeks and permitted a prolonged escalation ^{[7] [9]}. No trial has reported week-by-week onset data in a form we could cite, and there is no product label describing expected timing.

The doses studied are 0.6, 2.4, 3.6 and 4.8 mg once weekly in the phase 2 obesity trial ^[3]; up to 0.3, 0.9, 1.8 and 2.7 mg once weekly, or 1.2 and 1.8 mg twice weekly, in the type 2 diabetes phase 2 trial ^[4]; 2.4, 4.8 and 6.0 mg once weekly in the MASH trial ^[5]; 1.8 mg and 4.8 mg once weekly and 2.4 mg twice weekly in the phase 1 study ^[2]; and 3.6 mg and 6.0 mg once weekly in the phase 3 SYNCHRONIZE trials ^{[7] [9]}. The cirrhosis study escalated from 0.3 mg to 6.0 mg over 24 weeks ^[6]. The highest dose we found in any trial is 6.0 mg once weekly.

These are reported for information only. There is no approved survodutide dosage because there is no approved product, and the trial doses were reached by slow escalation under medical supervision with the option to lower the dose if it was not tolerated. Research vials labelled with a milligram amount have not been shown to contain that amount. Our peptide calculator explains the arithmetic of reconstitution, and the bacteriostatic water guide covers the diluent, but neither makes an unlicensed vial into a trial dose.

All survodutide trials used subcutaneous injection, once weekly in most and twice weekly in some early dose groups ^{[2] [4]}. Research suppliers sell survodutide as a freeze-dried powder, which is not a form that has been tested in any trial. No oral form has been studied.

The survodutide side effects seen in trials are gastrointestinal and dose-related, and they occur at high rates. In the phase 2 obesity trial, 75% of those on survodutide had gastrointestinal adverse events against 42% on placebo ^[3]. In SYNCHRONIZE-1, gastrointestinal events affected 80.9% on 3.6 mg and 89.7% on 6.0 mg against 47.9% on placebo, mostly mild to moderate ^[7]. In the MASH trial the specific rates were nausea 66%, diarrhoea 49% and vomiting 41% ^[5]. In the phase 1 study, decreased appetite was reported by two-thirds of participants and was the main reason people stopped escalating ^[2].

Dropout is the other recurring finding. Only 60.4% of participants completed the 46-week phase 2 obesity trial, at similar rates on drug and placebo ^[3], and 37% of those on survodutide in the phase 1 study withdrew from escalation ^[2]. Serious adverse events in the MASH trial were 8% on survodutide against 7% on placebo, and no deaths were reported in SYNCHRONIZE-1 ^{[5] [7]}. Glucagon receptor activation can raise heart rate and blood glucose, and the trials monitored both; the type 2 diabetes trial found glucose fell rather than rose ^[4].

The published abstracts do not report hair loss, fatigue, pancreatitis or gallbladder rates, and there is no label. Cardiovascular safety is the question SYNCHRONIZE-CVOT was designed to answer ^[10]; the registry lists it as completed but we found no results as of September 2026 ^[14]. Material bought online carries additional, unquantified risk. The FDA has warned companies selling survodutide labelled “for research purposes” or “not for human consumption” that were selling it to consumers with dosing instructions ^[15].

Survodutide vs mazdutide is the natural comparison, because both are glucagon and GLP-1 receptor dual agonists. Neither has been tested against the other. In separate trials, mazdutide 6 mg produced 14.01% weight loss at 48 weeks in Chinese adults with a mean BMI of 31.1 ^[17], and survodutide 4.8 mg produced 14.9% at 46 weeks in an international population with a BMI of at least 27 ^[3]. Mazdutide is approved in China; survodutide is approved nowhere. Our mazdutide guide covers its GLORY and DREAMS trials.

Survodutide vs retatrutide compares a dual agonist with a triple agonist. Retatrutide adds GIP receptor activity and produced 24.2% weight loss at 48 weeks on 12 mg in its phase 2 trial ^[18], against survodutide’s 14.9% at 46 weeks ^[3]. Both trials had heavier populations than the Chinese mazdutide trials, but different doses, escalation schedules and dropout rates still make a direct comparison unreliable. Survodutide vs tirzepatide has no head-to-head data either; tirzepatide is licensed, and our retatrutide vs tirzepatide page covers how licensed and investigational drugs in this family compare. For the whole category see peptides for weight loss.

As of September 2026, survodutide is not approved as a medicine by the FDA, the UK MHRA, the European Medicines Agency, the Australian TGA or, as far as we could find, any other regulator. Boehringer Ingelheim has published phase 3 results in obesity and fatty liver disease ^{[7] [8]}, and a completed cardiovascular outcomes trial is on the registry ^[14], but publication is not approval. Any filing and decision would follow.

The FDA names survodutide among the unapproved GLP-1 drugs it has warned about and says it has warned companies illegally selling it under a research label ^[15]. See the US legal status page and our news report on the FDA warnings to research-use GLP-1 sellers. In the UK, survodutide is unlicensed; see the UK legal status page. The position is the same in Europe and Australia. A vial of survodutide sold as a research product is not a licensed medicine anywhere. Our legal status overview explains how each country treats unlicensed peptides.

The only route to survodutide under medical supervision is a registered clinical trial. The SYNCHRONIZE and LIVERAGE programmes are listed on ClinicalTrials.gov ^{[13] [14] [19]}.

No product label exists, so there are no manufacturer storage instructions. Research material is sold as a freeze-dried powder; general practice is to keep it cold, dry and away from light and to refrigerate it once reconstituted. See how to store peptides. Any storage claim on a vendor website is the vendor’s own.

PepFinder does not sell survodutide. If you are comparing research suppliers, see compare survodutide prices, read how to read a COA, and check our list of third-party tested suppliers. A certificate should report a measured mass consistent with the molecular weight of about 4232 g/mol and state the quantity in the vial, not only its purity.

We track listings in the UK, the US, Canada, Australia and Europe. No published study has tested the content of research-grade survodutide that we could find. Our guides to third-party peptide testing, spotting a fake supplier and peptide prices explained cover what to check before trusting a listing.