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Home › GLP-1 clinics › GLP-1 Weight Loss Calculator
| Medication & dose | Average loss | Placebo | Length | Trial |
|---|---|---|---|---|
| Zepbound (tirzepatide) 15 mg | 20.9% | 3.1% | 72 weeks | SURMOUNT-1 |
| Zepbound (tirzepatide) 10 mg | 19.5% | 3.1% | 72 weeks | SURMOUNT-1 |
| Zepbound (tirzepatide) 5 mg | 15.0% | 3.1% | 72 weeks | SURMOUNT-1 |
| Wegovy (semaglutide) 2.4 mg injection | 14.9% | 2.4% | 68 weeks | STEP 1 |
| Wegovy pill (oral semaglutide) 25 mg | 13.6% | 2.2% | 64 weeks | OASIS 4 |
| Foundayo (orforglipron) 17.2 mg | 11.2% | 2.1% | 72 weeks | ATTAIN-1 |
| Foundayo (orforglipron) 9 mg | 8.4% | 2.1% | 72 weeks | ATTAIN-1 |
| Foundayo (orforglipron) 5.5 mg | 7.5% | 2.1% | 72 weeks | ATTAIN-1 |
Figures are mean percent change in body weight for all randomized participants (treatment-policy / treatment-regimen estimand), as published by the manufacturers and trial investigators: SURMOUNT-1 (NEJM 2022), STEP 1 (NEJM 2021), OASIS 4 (Novo Nordisk, 2025) and ATTAIN-1 (Lilly medical information, Foundayo tablet-equivalent doses). Every trial combined medication with diet and activity counseling.
In the major trials, average weight loss ranged from about 7.5% (Foundayo 5.5 mg) to about 21% (Zepbound 15 mg) over 64 to 72 weeks. Individual results vary a lot, and stopping the medication usually leads to weight regain.
In head-to-head and separate trials, tirzepatide (Zepbound) produced more average weight loss than semaglutide 2.4 mg (Wegovy). The right medication depends on your health history, side effects, cost and coverage, so decide with your clinician.
Some of the weight lost is lean mass. DEXA sub-studies found roughly a quarter to two-fifths of the weight lost was lean tissue. Eating enough protein, strength training and tracking with a DEXA scan help protect muscle.
Doses are increased gradually over the first few months, so most weight loss happens after you reach your maintenance dose. Trial participants were still losing weight around one year in.
This tool is for general education only. It is not medical advice and cannot tell you whether a medication is right for you. Results vary widely from person to person. Talk with a licensed clinician before starting, stopping or changing any medication. Last reviewed October 27, 2026.