How to use it
- Step 1Pick a medicine and maintenance dose.
- Step 2Enter your starting weight.
- Step 3Slide to the week you want to see, from 4 to 72.
- Step 4Read your projected loss, the trial average and the placebo result, with a chart.
Explainer · 0:23
Read the transcript
- After you eat, your gut releases a hormone called GLP-1. GLP-1 medicines copy it, but last much longer in the body.
- It slows how fast your stomach empties, so you feel full sooner and stay full for longer.
- It also acts on appetite centers in the brain, which quiets hunger and constant thoughts about food.
- When blood sugar is high, it helps the pancreas release insulin. Tirzepatide also acts on a second gut hormone, GIP.
Where the numbers come from
| Medicine and dose | Trial | Weeks | Average loss | Placebo |
|---|---|---|---|---|
| Zepbound 15 mg | SURMOUNT-1 | 72 | 20.9% | 3.1% |
| Zepbound 10 mg | SURMOUNT-1 | 72 | 19.5% | 3.1% |
| Zepbound 5 mg | SURMOUNT-1 | 72 | 15.0% | 3.1% |
| Wegovy 2.4 mg | STEP 1 | 68 | 14.9% | 2.4% |
| Wegovy pill 25 mg | OASIS 4 | 64 | 13.6% | 2.2% |
| Saxenda 3 mg | SCALE | 56 | 8.0% | 2.6% |
These are average results in people without type 2 diabetes. People with diabetes usually lost less in companion trials.
How the curve is modeled
The curve is a smooth model shaped to hit each trial's published endpoint: loss rises fast early and levels off, the way trial curves did. It's a planning tool, not trial data for a given week.
Worked example: 220 lb on the Zepbound 15 mg curve: about 20.9% by week 72, roughly 46 lb, if you match the trial average.
Why your result may differ
Results in the trials ranged widely: some people lost far more than average, some lost little. Your dose, how long you stay on it, diet, activity, sleep and other medicines all matter. For head-to-head data see Zepbound vs Wegovy.
Prefer a chart? See Zepbound weight-loss by start weight: precomputed tables for common inputs.
More glp-1 tools
GLP-1 dose schedule
Your titration calendar with calendar export
OpenSide-effect timeline
What the label reports at your dose step and week
OpenGLP-1 cost and savings
List, self-pay and savings-card prices side by side
OpenTDEE on a GLP-1
Your calorie needs vs what you actually eat now
OpenTirzepatide dose calculator
Where you are on the Zepbound or Mounjaro ladder
OpenWeigh-in tracker
Log weekly and compare with the trial curve
OpenCommon questions
How much weight can you lose on Zepbound?
In SURMOUNT-1, people without diabetes lost an average of 15.0% to 20.9% of body weight over 72 weeks, depending on dose.
How much weight can you lose on Wegovy?
In STEP 1, the average was 14.9% over 68 weeks on 2.4 mg, compared with 2.4% on placebo.
How fast does weight come off on a GLP-1?
Loss is fastest in the first months and slows toward a plateau, often somewhere after 6 to 12 months of treatment.
Will I keep the weight off if I stop?
Trial extensions found most people regained much of the weight within a year of stopping. See our guide on stopping a GLP-1.
Is this projection medical advice?
No. It applies average trial results to your starting weight. Your prescriber can tell you what's realistic for you.
Sources
- Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). NEJM 2022
- Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). NEJM 2021
- Pi-Sunyer X et al. A randomized, controlled trial of 3.0 mg of liraglutide in weight management (SCALE). NEJM 2015
- DailyMed: FDA prescribing information (search by drug name)
Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error