GLP-1 weight-loss calculator: understand the trial averages
Translate a published average percentage into pounds at a starting weight. This is arithmetic, not a prediction of your outcome, a dose recommendation or a comparison of which medicine is best.
Sources checked September 9, 2026 by Iacob Pastina, independent researcher and publisher. No clinical review is claimed.
Which evidence is used?
These are trial groups of adults with obesity or overweight without diabetes, alongside lifestyle support. Different study designs and endpoints prevent a direct ranking of treatments. The Foundayo figure uses the current label’s intention-to-treat analysis, rather than an estimate restricted to participants who stayed on treatment.
- STEP 1: 14.9% mean reduction at 68 weeks; placebo 2.4%. Semaglutide 2.4 mg weekly.
- SURMOUNT 1 / label Study 1: 20.9% mean reduction at 72 weeks; placebo 3.1%. Tirzepatide 15 mg weekly.
- Foundayo label Trial 1, intention-to-treat analysis: 11.1% mean reduction at 72 weeks; placebo 2.1%. Orforglipron 17.2 mg tablet-equivalent dose.
Why are there no compounded forecasts or weekly milestones?
Brand trials do not establish the effect of a particular compounded preparation. FDA explains that compounded products do not receive premarket review for safety, quality or effectiveness. The old calculator’s compounded estimates and claimed percentile ranges were unsupported and have been removed.
An endpoint average also cannot tell us your week-by-week path. Dividing it evenly across months would create precision the evidence does not provide. Ask your clinician how they will assess progress, side effects and whether treatment is appropriate for you.
For information only. This tool does not assess eligibility or give medical advice. Drafted with AI assistance and checked against the linked study sources.