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Type 2 DiabetesAugust 2023Summary reviewed June 2026

What the SURMOUNT-2 Trial Found — Tirzepatide for Weight Loss in Type 2 Diabetes

Researchers tested tirzepatide, a once-weekly injection, in 938 adults with type 2 diabetes and obesity. After 72 weeks, people taking tirzepatide lost significantly more weight than those on placebo, with most losing at least 5% of their body weight.

What the trial was testing

The SURMOUNT-2 enrolled 938 patients with type 2 diabetes. The study was sponsored by Eli Lilly and Company and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

People taking tirzepatide lost up to 15% of their body weight over 72 weeks, compared to 3% with placebo.

Lancet (London, England) · 2023 · NCT04657003

These findings — that people on the higher dose lost 15% of their body weight versus 3% on placebo — were published in the Lancet (London, England) and represent the headline result of the study.

Researchers tracked outcomes across 938 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with type 2 diabetes, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Tirzepatide is FDA-approved for type 2 diabetes and weight management. It's available now under brand names including Mounjaro (for diabetes) and Zepbound (for weight management). If you have type 2 diabetes and are struggling with weight, talk to your doctor about whether tirzepatide might be right for you.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.