Survodutide: Weight Loss Results, Side Effects, and Approval Status

Survodutide is an experimental once-weekly injection for weight loss that combines two drug actions in one molecule: it activates both the glucagon receptor and the GLP-1 receptor [1, 2]. In its main Phase 3 trial, adults with obesity or overweight, without type 2 diabetes, lost up to an average of 16.6% of their body weight after 76 weeks, compared with 3.2% for placebo — a difference that was statistically significant (p<0.0001) ^[1]. That works out to as much as 39.2 lb (17.8 kg) lost from baseline ^[1].

The drug is not approved anywhere. It is investigational, its efficacy and safety have not been established, and there is no prescription version to buy in the United States or any other country ^[1]. Clinical trials are how the drug is being tested, and additional trial results are expected to read out during 2026 ^[1]. For patients with serious conditions who cannot join a trial, expanded access is a separate FDA pathway for unapproved products, and each study record lists its own availability status ^[3].

What is survodutide and who makes it?

Survodutide, also known by its development code BI 456906, is a glucagon/GLP-1 receptor dual agonist given as a once-weekly injection under the skin [1, 2]. It is being developed by Boehringer Ingelheim, which licensed it from Zealand Pharma; Boehringer Ingelheim is solely responsible for its global development and commercialization ^[1].

The doses studied in the Phase 3 obesity trial were 3.6 mg and 6.0 mg per week, alongside a placebo arm [1, 2].

How is it different from GLP-1-only drugs?

The GLP-1 receptor activity works the familiar way for this class — it decreases appetite and increases fullness and satiety ^[1]. What makes survodutide unusual is its second action: it also activates the glucagon receptor [1, 2].

Glucagon agonism is thought to act directly on the liver to reduce hepatic fat, regulate metabolic function, resolve inflammation, and improve fibrosis ^[1]. Matthias Tschöp, MD, of Ludwig Maximilian University of Munich, one of the researchers behind the approach, put it this way: “Glucagon can drive energy expenditure. It can help with burning calories, thermogenesis, metabolism, maybe even contribute to satiation” ^[2].

The idea traces back more than two decades to oxyntomodulin, a natural peptide hormone that stimulates both the glucagon and GLP-1 receptors. Early work in rodents and primates showed that combined activation of both receptors produced greater fat loss than GLP-1 activation alone, without the blood-sugar-raising problem of a pure glucagon drug ^[2].

How much weight did people lose in the SYNCHRONIZE-1 trial?

SYNCHRONIZE-1 (NCT06066515) was a Phase 3, double-blind, randomized, placebo-controlled trial lasting 76 weeks [1, 2]. It enrolled 725 adults with a BMI of 30 or greater, or 27 or greater with at least one obesity-related complication, and it excluded people with type 2 diabetes [1, 2].

Participants were randomized 1:1:1 to once-weekly survodutide at 3.6 mg (n=241), 6.0 mg (n=242), or placebo (n=242), all with counseling for a reduced-calorie diet and increased physical activity ^[2]. The trial ran at 116 sites in 14 countries between November 2023 and February 2026 ^[2].

The headline results at week 76:

Measure	3.6 mg	6.0 mg	Placebo
Weight change, efficacy estimand	−15.3%	−16.6%	−3.2%
Weight change, treatment-regimen estimand	−12.2%	−13.0%	−5.4%
Achieved ≥20% weight loss	—	28.5%	6.6%

The efficacy-estimand result of up to −16.6% versus −3.2% for placebo was statistically significant at p<0.0001 ^[1]. The treatment-regimen comparisons of −12.2% and −13.0% versus −5.4% were significant at P<.001 ^[2].

On the share of people losing at least 5% of body weight, the two available reports differ. Boehringer Ingelheim’s topline announcement said up to 85.1% of survodutide-treated adults hit that mark versus 38.8% on placebo (p<0.0001) ^[1]. AJMC’s report on the full data gave 72.6% and 71.9% for the survodutide groups versus 46.3% on placebo ^[2].

The trial also met a key secondary endpoint, a statistically significant reduction in waist circumference versus placebo ^[1].

The study population started with a mean BMI of 37.9 and a mean weight of 108.8 kg, and nearly 70% had at least one obesity-related complication — most commonly hypertension (40.1%), dyslipidemia (33.9%), and obstructive sleep apnea (18.3%) ^[2]. In clinical discussions of the data, females on the 6.0 mg dose lost more weight than males, roughly 19.5% versus 12.6%, a pattern also seen across the GLP-1 class ^[2].

Topline results were announced on April 28, 2026, with full data presented at the American Diabetes Association’s 2026 Scientific Sessions in June and published simultaneously in the New England Journal of Medicine [1, 2].

Why are two different weight-loss percentages quoted?

The two figures come from two different statistical methods, called estimands, that answer different questions ^[2].

The efficacy estimand models the effect if everyone follows the protocol exactly — it answers “how well does the drug work when taken as directed?” Under that method, weight loss reached −15.3% at 3.6 mg and −16.6% at 6.0 mg, versus −3.2% for placebo [1, 2].

The treatment-regimen estimand accounts for people who stopped treatment early or deviated from the protocol — closer to “what happens in real use?” Under that method, weight loss was −12.2% at 3.6 mg and −13.0% at 6.0 mg, versus −5.4% for placebo ^[2].

The placebo number deserves a caveat. The placebo group lost 5.4% of body weight, well above the 2% to 3% the researchers had assumed when calculating the trial’s size. Investigators attributed part of that to crossover use: more than 16% of the placebo group reported using a prohibited GLP-1-based medication while still enrolled in the trial, a reflection of how widely commercial obesity drugs became available during the trial period ^[2]. Investigators link the finding to a broader shift in the field toward usual-care comparators and persistence-focused titration strategies ^[2].

What did the MRI substudy show about liver fat and visceral fat?

A prespecified MRI substudy of 25 participants per arm produced some of the most distinctive findings in the trial ^[2].

At the 6.0 mg dose, liver fat fell 63.1% from baseline to week 76, versus 24.5% in the placebo group. Visceral fat volume — the fat packed around internal organs — dropped 34.0%, versus 11.8% with placebo. Lean body volume declined 9.8%, meaning more than 89% of the total tissue change was fat mass, not lean mass ^[2].

Boehringer Ingelheim’s topline analysis similarly indicated that weight reduction was driven predominantly by fat tissue, with lean mass contributing only a small proportion of total weight lost ^[1].

Lee Kaplan, MD, PhD, director of The Obesity and Metabolism Institute at Massachusetts General Hospital and chair of the SYNCHRONIZE program executive committee, noted that the liver fat reductions appeared earlier in treatment than would be expected from weight loss alone, and were more pronounced at the 6.0 mg dose even though weight loss was similar across doses. He argued this suggests a mechanism beyond caloric restriction — glucagon receptor agonism acting directly on the liver ^[2].

One caution: these organ-fat numbers come from a 25-per-arm substudy, not the full 725-person trial population ^[2].

What did the liver disease trial find?

A second Phase 3 trial, SYNCHRONIZE-MASLD (NCT06309992), enrolled a subpopulation of adults with a confirmed or presumed diagnosis of MASH ^[1]. It tested survodutide 6.0 mg against placebo in 218 adults with obesity or overweight and metabolic dysfunction–associated steatotic liver disease (MASLD), with and without type 2 diabetes, over 48 weeks, using a 2:1 randomization ^[2].

The trial met both co-primary endpoints ^[2]. Under the efficacy estimand, up to 84.2% of survodutide-treated participants achieved at least a 30% relative reduction in liver fat by week 48, versus 24.3% on placebo (P<.0001). Body weight fell by up to 12.2% with survodutide versus 1.0% with placebo ^[2].

A prespecified secondary endpoint found that 61.0% of treated participants achieved liver fat normalization — liver fat content below 5% measured by MRI — versus 5.7% on placebo ^[2].

The study population had an average age of 55, a BMI of 39.6, and 38.4% had type 2 diabetes. Baseline liver fat averaged 16.9% by MRI ^[2].

Kaplan placed the numbers in context: in the published literature, a 30% reduction in liver fat has been associated with improvement in MASH activity, and a 50% reduction has been linked to improvement in fibrosis stage. The reductions in this trial exceeded both thresholds ^[2]. Improvements in alanine transaminase (ALT), a liver inflammation biomarker, were also observed as a secondary endpoint ^[2].

What are the side effects, and how many people quit over them?

The safety picture was dominated by gastrointestinal events — nausea, vomiting, diarrhea, and constipation — which were more frequent with survodutide than placebo and occurred most often during the dose escalation phase [1, 2].

These events led people to stop treatment in meaningful numbers. In SYNCHRONIZE-1, GI events caused discontinuation in 17.8% of the 3.6 mg group and 20.2% of the 6.0 mg group, versus 2.9% on placebo ^[2].

Boehringer Ingelheim characterized the events as mild to moderate in severity and temporary, with no new safety concerns beyond what is expected for the GLP-1 class ^[1].

Other safety findings from the reported data ^[2]:

• No deaths were reported.
• No adjudication-confirmed major adverse cardiovascular events occurred in the survodutide arms; one confirmed ischemic stroke occurred in the placebo group.
• No confirmed cases of pancreatic cancer, thyroid cancer, or acute pancreatitis. Asymptomatic pancreatic hyperenzymemia was slightly more common in the survodutide groups.
• Heart rate rose by 3.2 to 3.5 beats per minute at week 76, consistent with known effects of the drug class.

Is survodutide FDA-approved?

No. Survodutide is investigational and has not been approved for use; its efficacy and safety have not been established ^[1]. There is no approved prescription product anywhere.

What do the FDA designations actually mean?

Survodutide has received several regulatory designations, all of them tied to its potential in liver disease ^[1]:

• FDA Fast Track designation in May 2021 ^[1]
• FDA Breakthrough Therapy designation in September 2024, for adults with non-cirrhotic MASH and moderate or advanced fibrosis (stage 2 or 3) ^[1]
• Acceptance to the European Medicines Agency’s PRIME scheme in November 2023 ^[1]
• Breakthrough Therapy designation from China’s NMPA Center for Drug Evaluation in June 2024 ^[1]
• Breakthrough Designation from the Taiwan FDA in September 2024 ^[1]

These designations do not mean the drug is approved, and they are not proof that the drug works or will be approved ^[1].

What other trials are still running?

Survodutide is part of a large Phase 3 program, and more results are expected to read out during 2026 ^[1].

The SYNCHRONIZE program includes ^[1]:

• SYNCHRONIZE-2 (NCT06066528): adults with type 2 diabetes
• SYNCHRONIZE-CVOT (NCT06077864): adults with cardiovascular disease, chronic kidney disease, or cardiovascular risk factors
• SYNCHRONIZE-JP (NCT06176365) in Japan and SYNCHRONIZE-CN (NCT06214741) in China; the Japan trial includes relative change in liver fat and body composition to week 76 as a secondary endpoint

Two global Phase 3 trials focus on MASH ^[1]:

• LIVERAGE (NCT06632444): approximately 1,800 adults with MASH and fibrosis stage 2 or 3
• LIVERAGE-Cirrhosis (NCT06632457): approximately 1,590 adults with compensated MASH cirrhosis (fibrosis stage 4)

In both LIVERAGE trials, participants receive weekly injections of survodutide up to a maximum of 6 mg, or placebo ^[1].

Beyond survodutide, Boehringer Ingelheim’s pipeline includes BI 3034701, an investigational triple GLP-1/GIP/NPY2 receptor agonist peptide entering Phase 2 in mid-2026, plus additional experimental approaches including oral treatment options ^[1].

Can I get survodutide in the United States?

Not by prescription. Survodutide is not approved for use anywhere, and no commercial prescription product exists ^[1].

Clinical trials are the route through which the drug is being tested. Boehringer Ingelheim lists its trial information at trials.boehringer-ingelheim.com, and the individual studies can be searched by their NCT numbers on ClinicalTrials.gov [10, 1].

For patients with serious conditions who cannot join a trial, expanded access (sometimes called compassionate use) is a separate FDA pathway for unapproved products; each study record on ClinicalTrials.gov lists its own expanded access status ^[3].

Why the focus on liver disease?

The liver findings matter because of how common the underlying problem is. More than 1 billion people worldwide live with obesity — about 1 in 8 — and in 2016 more than 1.9 billion adults had overweight (BMI 25 or greater), of whom over 650 million had obesity (BMI 30 or greater) ^[1].

An estimated 34% of people with obesity also have MASH — up to 1 in 3 — a condition marked by inflammation and liver damage ^[1]. In the United States, MASH cases are projected to rise 63% between 2015 and 2030, from 16.5 million to 27.0 million ^[1].

Sources

1. Boehringer Ingelheim. Results from Phase III SYNCHRONIZE-1 obesity trial. April 28, 2026.
2. AJMC. Survodutide Phase 3 Data Signal Metabolic Gains Beyond Weight Loss. June 8, 2026.
3. ClinicalTrials.gov. A Study to Test Whether Survodutide (BI 456906) Helps People Living With Overweight or Obesity Who do Not Have Diabetes to Lose Weight (NCT06066515).
4. ClinicalTrials.gov. A Study to Test Whether Survodutide (BI 456906) Helps People Living With Overweight or Obesity Who Also Have Diabetes to Lose Weight (NCT06066528).
5. ClinicalTrials.gov. A Study to Test the Effect of Survodutide (BI 456906) on Cardiovascular Safety in People With Overweight or Obesity (SYNCHRONIZE-CVOT) (NCT06077864).
6. ClinicalTrials.gov. A Study to Test Whether Survodutide Helps People With NASH Reduce Liver Fat and Lose Weight (SYNCHRONIZE-MASLD) (NCT06309992).
7. ClinicalTrials.gov. LIVERAGE: A Study to Test Whether Survodutide Helps People With NASH/MASH Who Have Moderate or Advanced Liver Fibrosis (NCT06632444).
8. ClinicalTrials.gov. LIVERAGE - Cirrhosis: A Study to Test Whether Survodutide Helps People With NASH/MASH Who Have Cirrhosis (NCT06632457).
9. ClinicalTrials.gov. A Study to Test Whether Survodutide Helps People With Type 2 Diabetes Control Their Blood Sugar (NCT07754461).
10. Boehringer Ingelheim. Medical & Clinical Trials | Clinical Research | BI Clinical Studies.
11. New England Journal of Medicine. Survodutide Once Weekly for the Treatment of Adults with Obesity.