How much weight do people lose on semaglutide or tirzepatide?
In the main trials, adults without diabetes lost an average of 14.9% of body weight on semaglutide 2.4 mg after 68 weeks (STEP 1) and 20.9% on tirzepatide 15 mg after 72 weeks (SURMOUNT-1, treatment-regimen estimand), against 2.4% and 3.1% on placebo. These are averages for people who also received diet and activity counseling; individual results vary widely and some people lose much less. Results in people with type 2 diabetes were smaller. No compounded product has trial results of its own, and no program can promise a specific amount of weight loss.
Answer dated October 16, 2026; reviewed by Dr. Jonathan Snipes, MD and Kim Callender, NP (FNP-BC).Established tirzepatide for chronic weight management and produced first FDA-approved drug for OSA.
SURMOUNT-1 — foundational
Jastreboff et al. (NEJM 2022): 2,539 adults with obesity, no diabetes. Weight loss at 72 weeks: 15.0% (5 mg), 19.5% (10 mg), 20.9% (15 mg) vs 3.1% (placebo). 57% at 15 mg lost ≥20%. Basis for Zepbound approval (Nov 2023). Under the efficacy estimand the 15 mg figure is 22.5%.
SURMOUNT-5 — head-to-head with semaglutide
SURMOUNT-5 (NEJM 2025): tirzepatide (maximum tolerated dose up to 15 mg) vs semaglutide (up to 2.4 mg) in adults with obesity without diabetes. Mean weight loss at 72 weeks: 20.2% vs 13.7%.
SURMOUNT-OSA — sleep apnea
Malhotra et al. (NEJM 2024): adults with moderate-severe OSA + obesity. AHI reduction −25.3 events/hr (tirz) vs −5.3 (placebo) in PAP-naive cohort at 52 weeks. ~50% achieved OSA disease remission. Basis for December 2024 FDA approval — first drug ever FDA-approved for OSA.
SURPASS-3 — head-to-head with insulin
Heise et al. (Lancet 2021): tirzepatide superior to titrated insulin degludec in T2D on A1c and weight, with lower hypoglycemia.
SURMOUNT-MMO — CV outcomes
Still running: ClinicalTrials.gov (NCT05556512) lists an estimated primary completion in October 2027, and no results have been reported. Separately, SURPASS-CVOT in type 2 diabetes led FDA to add a CV indication for Mounjaro on August 27, 2026; that indication does not cover Zepbound.
Implications
- Tirzepatide produces larger weight loss than single-agonist GLP-1s
- Only FDA-approved pharmacotherapy for OSA
- CV indication now on Mounjaro (T2D, August 2026); no MASH or CV indication for Zepbound as of October 16, 2026