GLP-1 Weight Loss Calculator (Ozempic / Wegovy / Mounjaro / Zepbound)
Project weight loss on Wegovy, Ozempic, Mounjaro, Zepbound, and Saxenda using STEP and SURMOUNT trial data. Monthly BMI trajectory and side effects.
HEALTHProject realistic weight loss on GLP-1 receptor agonists - Wegovy, Ozempic, Mounjaro, Zepbound, Saxenda, Rybelsus, and compounded semaglutide - using STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide) clinical trial data.
Models a typical titration curve toward the documented peak weight loss for each medication, adjusted by your lifestyle adherence (low, moderate, high). Outputs projected weight, BMI before and after, BMI category transition, month-by-month projection, common side-effect rates from trials, and a lean-mass-preservation note.
GLP-1 Weight Loss Calculator (Ozempic / Wegovy / Mounjaro / Zepbound)
Project realistic weight loss on GLP-1 receptor agonists based on STEP and SURMOUNT clinical trial data. Compare drugs, see your BMI trajectory month by month, and understand the typical side-effect profile.
Month-by-Month Projection
| Month | Weight | BMI |
|---|---|---|
| 1 | 214.0 lbs | 32.5 |
| 2 | 209.1 lbs | 31.8 |
| 3 | 204.9 lbs | 31.2 |
| 4 | 201.4 lbs | 30.6 |
| 5 | 198.4 lbs | 30.2 |
| 6 | 196.0 lbs | 29.8 |
| 7 | 193.9 lbs | 29.5 |
| 8 | 192.2 lbs | 29.2 |
| 9 | 190.7 lbs | 29.0 |
| 10 | 189.5 lbs | 28.8 |
| 11 | 188.5 lbs | 28.7 |
| 12 | 187.6 lbs | 28.5 |
Common Side Effects (Trial Data)
How GLP-1 Medications Work
GLP-1 receptor agonists mimic the gut hormone glucagon-like peptide-1, which slows gastric emptying, increases satiety, and reduces appetite. The newer dual-action drugs (tirzepatide) also activate the GIP receptor, producing a stronger metabolic effect.
Clinical-trial averages: STEP 1 found Wegovy delivers about 14.9% body weight loss at 68 weeks vs 2.4% placebo. SURMOUNT-1 showed tirzepatide 15mg delivered about 20.9% at 72 weeks. Real-world results are typically 25-30% lower than trial numbers due to adherence and titration drop-off.
Most weight loss occurs in months 3-12 as you titrate to the maintenance dose. The plateau usually arrives around month 14-18. Stopping the drug typically leads to two-thirds of lost weight returning within a year if lifestyle changes are not sustained.
Educational tool only. Numbers reflect clinical-trial averages - individual results vary substantially based on starting weight, metabolic health, adherence, and titration speed. Not medical advice. Always work with a licensed prescriber to determine if a GLP-1 is right for you, manage side effects, and monitor labs.