This GLP-1 weight loss calculator applies the average result of each medication’s main clinical trial to your current weight. It shows how much people lost on Zepbound®, Wegovy® or Saxenda® in those trials, and how that compares with placebo. It helps you understand the evidence; it is not a prediction of your own result.
GLP-1 weight loss calculator
See the average weight loss in the main clinical trial of three FDA-approved GLP-1 injections (Zepbound®, Wegovy®, Saxenda®), applied to your weight.
Averages from randomized trials in adults without diabetes who had obesity, or overweight with a weight-related condition, alongside diet and activity counseling. People with type 2 diabetes lost less on average in separate trials. Individual results ranged widely: some people lost much more than the average, and some lost little or none. These medications are only labeled for adults with a BMI of 30 or more, or 27 or more with a weight-related condition: check your BMI. Results stop or reverse for many people after stopping treatment. Compounded versions were not studied in these trials and are not FDA-approved. This is not a prediction for you and not medical advice: talk to your healthcare provider.
Not for everyone: these medications are not used during pregnancy or breastfeeding, and are not appropriate for people with a personal or family history of medullary thyroid cancer or MEN2. Tell your clinician if you have had pancreatitis, gallbladder, kidney or eye (diabetic retinopathy) problems, an eating disorder, or take insulin or other diabetes medicines. Zepbound can make birth-control pills less effective.
How the GLP-1 weight loss calculator works
The calculator multiplies your weight by the average percentage of body weight lost in the trial you select. It also shows what participants on placebo lost, since they received the same diet and activity counseling. Everything is calculated in your browser: nothing you type is sent or saved.
| Medication and dose | Trial | Average loss | Duration | Placebo |
|---|---|---|---|---|
| Tirzepatide 15 mg (Zepbound®) | SURMOUNT-1 (NEJM, 2022) | 20.9 % | 72 weeks | 3.1 % |
| Tirzepatide 10 mg (Zepbound®) | SURMOUNT-1 (NEJM, 2022) | 19.5 % | 72 weeks | 3.1 % |
| Tirzepatide 5 mg (Zepbound®) | SURMOUNT-1 (NEJM, 2022) | 15.0 % | 72 weeks | 3.1 % |
| Semaglutide 2.4 mg (Wegovy®) | STEP 1 (NEJM, 2021) | 14.9 % | 68 weeks | 2.4 % |
| Liraglutide 3.0 mg (Saxenda®) | SCALE (NEJM, 2015) | 8.0 % | 56 weeks | 2.6 % |
The figures come from the published papers: SURMOUNT-1 on tirzepatide, STEP 1 on semaglutide and SCALE on liraglutide. Participants were adults without diabetes who had obesity, or overweight with a weight-related condition.
How to read your result
Take a 230 lb person who selects Wegovy®. The calculator shows about 34 lb (14.9 %) after 68 weeks, compared with about 6 lb (2.4 %) on placebo. Read it this way:
- It is a group average. In each trial, some people lost much more and some lost little or none.
- The gap with placebo is the medication’s effect. The placebo line shows what counseling alone achieved in the same study.
- The timeline is long. These are results after more than a year, reached gradually as the dose was increased.
- The trials are not head-to-head. They ran in different years with different people, so the numbers are not a direct ranking of the drugs.
Limits of this calculator
- People with type 2 diabetes lost less on average, in separate trials not used here.
- Compounded semaglutide and tirzepatide were not tested in these trials and are not FDA-approved.
- Newer options, such as the Wegovy® pill, the higher 7.2 mg Wegovy® dose or Foundayo™ (orforglipron), are not included yet.
- Results often stop or reverse after treatment stops.
- The safety note under the calculator lists who should not use these medications. Your own clinician decides whether one fits you.
Frequently asked questions
Is this calculator a prediction of my weight loss?
No. It applies a trial average to your weight, nothing more. Your result depends on your health, your dose, how long you stay on treatment, side effects and many other factors. Only a clinician who knows your history can discuss what to expect.
Why does Zepbound show more weight loss than Wegovy?
In their own trials, tirzepatide 15 mg averaged 20.9 % and semaglutide 2.4 mg averaged 14.9 %, but those were separate studies. Tirzepatide acts on two hormone receptors (GIP and GLP-1), while semaglutide acts on GLP-1 only.
Do compounded GLP-1s give the same results?
There is no trial evidence to say so. Compounded versions were not part of SURMOUNT-1, STEP 1 or SCALE, and the FDA does not review them for safety, effectiveness or quality. The averages above apply only to the brand-name medications studied.
Who can get these medications?
The FDA labels cover adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition. A clinician then checks your health history and other medications. The BMI calculator shows where you stand.
What to read next
- Check your BMI against the FDA label criteria
- Compare weight-loss program prices this month
- Estimate your real cost over 12 months
Read more in our methodology and talk to your healthcare provider before starting any medication.