What the trials saw,
at your weight.
This applies the mean weight change from each medication’s pivotal trial to your starting weight. It tells you what an average participant lost. Individual results in those same trials ranged from no loss to more than 25%, which is why this is an average and not a forecast for you.
TRIAL-AVERAGE OUTCOME
—How it’s calculated
Projected weight = starting weight × (1 − trial mean % change) Semaglutide 2.4 mg: −14.9% at 68 weeks (placebo −2.4%) STEP 1 Tirzepatide 15 mg: −20.9% at 72 weeks (placebo −3.1%) SURMOUNT-1 Tirzepatide 10 mg: −19.5% at 72 weeks SURMOUNT-1 Tirzepatide 5 mg: −15.0% at 72 weeks SURMOUNT-1 Liraglutide 3.0 mg: −8.0% at 56 weeks (placebo −2.6%) SCALE
Assumptions and limits
- Trial participants had BMI ≥ 30 (or ≥ 27 with a comorbidity), received lifestyle counselling, and completed the full titration. Results outside those conditions differ.
- Means hide wide variation. In STEP 1 roughly a third of participants lost 20% or more and some lost under 5%.
- Weight regain after stopping is well documented (STEP 1 extension). This estimates on-treatment change only.
- Not a prediction, a recommendation, or a reason to choose one drug over another. That is a prescriber’s conversation.
References
- Tirzepatide Once Weekly for the Treatment of Obesity.N Engl J Med 2022.PubMed 35658024 · doi:10.1056/NEJMoa2206038
- Once-Weekly Semaglutide in Adults with Overweight or Obesity.N Engl J Med 2021.PubMed 33567185 · doi:10.1056/NEJMoa2032183
- Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension.Diabetes Obes Metab 2022.PubMed 35441470 · doi:10.1111/dom.14725
- Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial.Nat Med 2024.PubMed 38740993 · doi:10.1038/s41591-024-02996-7
- Tirzepatide for Obesity Treatment and Diabetes Prevention.N Engl J Med 2025.PubMed 39536238 · doi:10.1056/NEJMoa2410819
- Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial.Lancet 2023.PubMed 37385275 · doi:10.1016/S0140-6736(23)01200-X
Literature retrieved from PubMed on October 18, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.