Clinical research

SURMOUNT-1: Tirzepatide in adults with obesity or overweight

Phase 3, randomised, double-blind, parallel-group, placebo-controlled. 2,539 randomised, over 72 weeks. Sponsor: Eli Lilly and Company.

SURMOUNT-1 (NCT04184622) tested tirzepatide once weekly at 5 mg, 10 mg or 15 mg against placebo in adults with obesity (bmi 30 or above), or overweight (bmi 27 or above) with at least one weight-related complication, without type 2 diabetes.Treatment-regimen estimand: −15.0% (5 mg), −19.5% (10 mg), −20.9% (15 mg) versus −3.1% placebo. Efficacy estimand: −16.0%, −21.4%, −22.5% versus −2.4% Primary source linked: the source is a citable peer-reviewed / registry record, which we have not independently re-extracted from the full paper in this session.

Study design

Results

Treatment-regimen estimand: −15.0% (5 mg), −19.5% (10 mg), −20.9% (15 mg) versus −3.1% placebo. Efficacy estimand: −16.0%, −21.4%, −22.5% versus −2.4%

Adverse events & discontinuations

At 15 mg: nausea 29%, diarrhoea 23%, constipation 17%, vomiting 13%, dyspepsia 10%. Mostly mild to moderate and concentrated during dose escalation

7% discontinued because of an adverse event at 15 mg

Limitations

Industry-funded and industry-analysed. Excludes people with type 2 diabetes. Two estimands are published and are routinely conflated: the treatment-regimen estimand includes everyone regardless of adherence, the efficacy estimand assumes continued treatment. Marketing generally quotes the higher figure without saying which. Results are group means under trial conditions with structured lifestyle support, and describe an FDA-approved subcutaneous injection at studied doses.

Practical interpretation

This is one trial, reported by Eli Lilly and Company, read directly against the registry and publication linked below — GLP Ranked has not re-run the statistics or obtained the patient-level data. Results describe group averages under trial conditions and may not describe any individual's outcome, including with a compounded, non-FDA-approved version of a similar active ingredient. Always check the primary source before citing a specific number.