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Tirzepatide · Phase 3 · Completed

SURMOUNT-1

In SURMOUNT-1, a phase 3 trial of tirzepatide in adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes (n=2,539), mean body weight fell 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg over 72 weeks, against 3.1% on placebo (treatment-regimen estimand; Jastreboff AM et al. N Engl J Med 2022;387:205-216).

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Updated 24 September 2026

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Results

SURMOUNT-1: mean percent change in body weight by armHorizontal bars, one group per trial: SURMOUNT-1, 5 mg -15.0%, 10 mg -19.5%, 15 mg -20.9%, Placebo -3.1%.SURMOUNT-1treatment-regimen estimand5 mg-15.0%10 mg-19.5%15 mg-20.9%Placebo-3.1%
Mean percent change in body weight by arm, as each source reports it. Navy bars are the trial arms, grey bars the comparator. Bars from different trials are not a head-to-head comparison: populations, durations and estimands differ.

Side effects reported

In SURMOUNT-1, discontinuation because of adverse events was 4.3% on 5 mg, 7.1% on 10 mg and 6.2% on 15 mg, against 2.6% on placebo.

Event5 mg10 mg15 mgPlacebo
Discontinuation for adverse events4.3%7.1%6.2%2.6%

Design

Trial design and sources

Compound
Tirzepatide
Phase
3
Population
Adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes
Participants randomised
2,539
Duration
72 weeks
Primary endpoint
Coprimary: percentage change in weight from baseline and weight reduction of 5% or more (week 72)
Estimand
treatment-regimen
Read out
4 June 2022

Treatment-regimen estimand, as the NEJM abstract reports it. Lilly's release (28 April 2022) gave 22.5% on 15 mg under the efficacy estimand; that figure is in lib/trials/tirzepatide.ts for like-for-like comparison with the TRIUMPH releases.

  • Jastreboff AM et al. N Engl J Med 2022;387:205-216 open · checked 23 September 2026
  • ClinicalTrials.gov NCT04184622 open · checked 23 September 2026
  • Registry: NCT04184622

Questions

SURMOUNT-1, answered

What did SURMOUNT-1 find?

In SURMOUNT-1, a phase 3 trial of tirzepatide in adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes (n=2,539), mean body weight fell 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg over 72 weeks, against 3.1% on placebo (treatment-regimen estimand; Jastreboff AM et al. N Engl J Med 2022;387:205-216).

What side effects were reported in SURMOUNT-1?

In SURMOUNT-1, discontinuation because of adverse events was 4.3% on 5 mg, 7.1% on 10 mg and 6.2% on 15 mg, against 2.6% on placebo.

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