Experimental Survodutide Led to Weight Loss of as Much as 13.1% in Adults with Type 2 Diabetes in Boehringer's Phase 3 Study

An experimental once-weekly injection known as survodutide helped adults with obesity or overweight and type 2 diabetes lose as much as 13.1% of their body weight over 76 weeks, compared with 3.1% for placebo. The phase 3 findings appeared in The New England Journal of Medicine and were presented at the European Association for the Study of Diabetes annual meeting.

The treatment has not been approved by the FDA, and the study was conducted by its developer, Boehringer Ingelheim. It also showed a notable limitation: 18% of participants taking survodutide discontinued because of gastrointestinal side effects, versus 1.2% in the placebo group.

For millions of Americans living with both obesity and type 2 diabetes, additional treatment choices could eventually matter if current medicines are difficult to tolerate, hard to obtain, or not covered. Even so, that potential remains years away, and these findings do not alter present-day care.

SYNCHRONIZE-2 Trial Findings

The SYNCHRONIZE-2 study included 755 adults with obesity or overweight and type 2 diabetes. According to reporting on the trial, participants were given weekly injections of survodutide at doses of 3.6 mg or 6.0 mg, or placebo.

As many as 79.3% of those treated with survodutide lost at least 5% of their body weight, compared with 32.7% on placebo. Average blood sugar, measured by HbA1c, declined by as much as 1.21 percentage points from a starting level of 7.4%, while placebo produced a 0.03-point drop.

Up to 29.5% of participants taking survodutide reached an HbA1c below 5.7%, which is considered the normal range, compared with 4.0% in the placebo arm. Waist circumference also fell by 11.1 centimeters, versus 3.5 centimeters with placebo.

People with type 2 diabetes often lose less weight on these medicines than people without the condition, and that pattern was seen here. In the earlier SYNCHRONIZE-1 trial, which enrolled adults with obesity or overweight but without type 2 diabetes, survodutide produced up to 16.6% average weight loss, according to company figures cited in reporting.

The 13.1% result is based on what researchers call the efficacy estimand, meaning it assumes participants stayed on therapy for the full study. Analyses that include everyone, including those who stopped treatment, are usually lower, and the company's headline figure does not reflect that difference.

"Seeing improvements in glycemic control and insulin sensitivity alongside weight loss provides evidence that tackling obesity can positively influence broader metabolic health," said Dr. Sean Wharton, coordinating investigator of the SYNCHRONIZE-2 trial.

One Injection, Two Hormone Targets

Survodutide works by acting on two hormone receptors. Like semaglutide, it stimulates the GLP-1 receptor, which slows stomach emptying, reduces appetite, and helps the body release insulin after meals.

It also activates the glucagon receptor. Glucagon is a hormone that increases energy expenditure and affects the liver, which is one reason the company is also studying survodutide for metabolic dysfunction-associated steatohepatitis, or MASH, a serious type of fatty liver disease.

That additional pathway distinguishes it from tirzepatide, sold as Zepbound and Mounjaro, which combines GLP-1 with another hormone, GIP. Whether the glucagon component delivers better long-term outcomes has not yet been proven.

The company also released body composition findings from a 75-person substudy of SYNCHRONIZE-1. Muscle made up no more than 10% of total tissue lost, and reductions in visceral fat and liver fat were also reported, according to coverage of the metabolic data. That substudy was small and did not include people with type 2 diabetes.

Evidence Check

SYNCHRONIZE-2 was a randomized, double-blind, placebo-controlled phase 3 trial, which is among the strongest study designs short of long-term outcomes research. It was sponsored by Boehringer Ingelheim, which licensed the drug from Zealand Pharma. Both companies would benefit financially if it reaches the market. The trial is registered as NCT06066528.

The study focused on weight loss and blood sugar, not on heart attacks, strokes, or mortality. A separate cardiovascular outcomes trial is still underway. And because the trial lasted 76 weeks, it cannot show what happens over many years or after treatment ends.

Comparisons with approved medications remain uncertain. Results from separate trials suggest survodutide may fall between semaglutide and tirzepatide for weight loss in people with type 2 diabetes, but differences across studies make firm conclusions impossible. Analysts at William Blair, quoted in reporting, described the earlier SYNCHRONIZE-1 findings as "more akin to Wegovy than Zepbound."

The clearest unresolved issue is tolerability. Most discontinuations tied to nausea, vomiting, diarrhea, and constipation occurred during dose escalation, and Boehringer said the study protocol allowed only limited flexibility to manage side effects. Ongoing and planned trials permit more flexible dosing schedules, but they have not yet shown whether slower increases will reduce dropouts.

What Patients Should Know

Survodutide is not available outside clinical trials, and no FDA filing date has been announced. People with type 2 diabetes should not change their current treatment based on these results.

Several approved drugs already address both blood sugar and weight, including semaglutide and tirzepatide. A clinician can help determine which option best fits a person's medical history, other medicines, and insurance situation.

Price and access remain barriers for existing treatments, and no pricing has been released for survodutide. People who qualify for an approved GLP-1 drug but run into coverage problems can ask about prior authorization, appeals, or manufacturer savings programs. Those interested in research participation can check ClinicalTrials.gov or speak with an endocrinologist.

Anyone taking an approved GLP-1 drug who develops severe abdominal pain, persistent vomiting, or signs of dehydration should contact a clinician promptly.

Boehringer expects cardiovascular outcomes data later in 2026. Those results, together with full regulatory review, will help determine whether survodutide becomes an option for patients.

Questions and Answers

What is survodutide? An experimental once-weekly injection from Boehringer Ingelheim that activates both GLP-1 and glucagon receptors to support weight loss and improve blood sugar.

How much weight did participants lose? Up to 13.1% of body weight over 76 weeks, compared with 3.1% on placebo, in adults with obesity or overweight and type 2 diabetes.

Is survodutide approved? No. It is not FDA-approved, and no filing date has been announced.

What side effects were reported? Mainly nausea, vomiting, diarrhea, and constipation. About 18% stopped treatment because of stomach side effects, versus 1.2% on placebo.

Who funded the study? Boehringer Ingelheim sponsored the trial and licensed survodutide from Zealand Pharma.

Should patients switch diabetes medication? No. People should speak with a clinician about approved options and should not change medication based on these findings.