On average, people lose about 15% of their body weight in a year on Wegovy, 21% on Zepbound or Mounjaro, 12% on Ozempic, and 7% on Saxenda — with most of the loss in the first 9 months. Enter your weight below to see your personalized 12-month projection.
Last updated: June 2026
This free calculator projects your month-by-month weight loss on GLP-1 medications using average trajectories from the major clinical trials (STEP, SURMOUNT, and SUSTAIN programs). Pick your medication, enter your current weight, and see where you could be in 12 months — including the typical range, because real results vary.
GLP-1 Weight Loss Projection Calculator
See your projected 12-month weight curve — based on average clinical trial results
Projected
Your 12-month projection
Based on average clinical trial results with lifestyle changes. Individual results vary widely. Not a prediction or medical advice. Shaded band shows the typical range (±25%).
ⓘ This tool is for informational purposes only and does not constitute medical advice, a prediction, or a guarantee of results. Projections are statistical averages from clinical trials; your results depend on dose, adherence, diet, activity, and individual biology. Always consult a licensed healthcare provider.
How accurate are these projections?
The curves come from the average results of the major clinical trials: the STEP program for Wegovy (~15% body weight loss at 68 weeks), the SURMOUNT program for tirzepatide/Zepbound (~21%), the SUSTAIN program and real-world data for Ozempic (~12% at doses up to 2mg), and the SCALE program for Saxenda (~7%). Compounded semaglutide is labeled "estimated" because compounded products are not FDA-approved and have no standardized trial data — we use the Ozempic curve as a proxy.
Averages hide a wide spread: roughly a third of people lose substantially more than average, and some lose substantially less. Dose escalation speed, side-effect tolerance, diet, resistance training, and genetics all shift the curve. That is why the chart shows a typical range band, not a single line of certainty.
What affects how much weight you lose on a GLP-1?
- Medication and dose — tirzepatide (Zepbound/Mounjaro) averages the most loss in trials; reaching full dose matters.
- Protein and resistance training — protects muscle so more of what you lose is fat. See our nutrition guide.
- Side-effect management — people who manage nausea early stay on therapy longer. See the side effects hub.
- Consistency — most discontinuation happens in the first 3 months, before the biggest losses arrive.
Not sure if you qualify for a GLP-1 in the first place? Start with the eligibility calculator, or compare costs in the cost & access hub.