The trial averages
The published average change in body weight at each trial’s endpoint, quoted from the paper. Each is a separate placebo-controlled trial in adults without diabetes, so read the rows side by side with care: they are not a head-to-head ranking. For the one head-to-head trial, see tirzepatide vs semaglutide.
| Medication | Trial | Weeks | Dose | Average loss | Placebo |
|---|---|---|---|---|---|
| Zepbound | SURMOUNT-1 | 72 | 15 mg | 20.9% | 3.1% |
| 10 mg | 19.5% | ||||
| 5 mg | 15% | ||||
| Wegovy | STEP 1 | 68 | 2.4 mg | 14.9% | 2.4% |
| Wegovy pill | OASIS 4 | 64 | 25 mg | 13.6% | 2.2% |
| Foundayo | ATTAIN-1 | 72 | 36 mg | 11.2% | 2.1% |
| 12 mg | 8.4% | ||||
| 6 mg | 7.5% |
Foundayo is orforglipron. ATTAIN-1’s NEJM paper reports 11.2% at 36 mg using its primary (treatment-regimen) analysis; Lilly’s press release quotes 12.4%, a different analysis of the same trial.
What the trial period costs, per pound
Worked for a 220 lb start at each trial's top dose: the total for the trial's length, divided by the pounds the average implies. The calculator above redoes this for your weight.
| Medication | Route | Total | Per lb |
|---|---|---|---|
| Zepbound 15 mg, 46 lb at the average | Lilly's self-pay price18 four-week fills: one at each label step up to 15 mg, then 15 mg at $449 a fill, read Oct 3. From 7.5 mg this uses the maker's purchase offer, which holds only while each refill is within 45 days of the last; at the regular price the top dose is $699 a month. | $7,882 | $171.42 |
| Compounded tirzepatide: SnagRxNot the product the trial tested, and not FDA-approved. $119 a month all-in for 17 months. Checked Oct 2. | $2,023 | $44.00 | |
| Wegovy 2.4 mg, 33 lb at the average | Novo's self-pay price17 four-week fills: $199 for the first two (Novo's new-patient offer), then $349, read Oct 3. | $5,633 | $171.84 |
| Compounded semaglutide: SnagRxNot the product the trial tested, and not FDA-approved. $69 a month all-in for 16 months. Checked Oct 2. | $1,104 | $33.68 | |
| Wegovy pill 25 mg, 30 lb at the average | Novo's self-pay price$299 a month at 25 mg for all 15 months. Starting doses cost less, so this is the ceiling. NovoCare, read Oct 2. | $4,485 | $149.90 |
| Foundayo 36 mg, 25 lb at the average | Lilly's self-pay price$299 a month (Lilly's top published tier) for all 17 months. The trial labels its doses differently from the strengths Lilly sells, so this is a ceiling, read Oct 3. From 14.5 / 17.2 mg this uses the maker's purchase offer, which holds only while each refill is within 45 days of the last; at the regular price the top dose is $349 a month. | $5,083 | $206.29 |
Telehealth programs that sell brand Zepbound or Wegovy charge the maker’s dose price plus their own fee, so they cost more than the maker rows above. Compounded rows use the program’s entry price; some charge more as the dose climbs, so ask before you sign up.
Want the month-by-month bill instead? Every dose step and its price is on the Zepbound and Wegovy pages, and the cost calculator totals any program over 1 to 12 months.
Program links pay us a commission. The order is the all-in monthly price, never what anyone pays us. How we earn.
How to read these numbers
- An average is the middle of a wide spread: in each trial some people lost far more and some lost little.
- Trials kept people on a fixed dose with regular visits. Stopping, pausing or a lower dose changes the result.
- These trials excluded people with diabetes, who tend to lose less on the same drugs.
- Your prescriber sets your dose. Nothing here is advice to start, stop or change one.
Weight loss calculator: common questions
How much weight do people lose on Zepbound?
In SURMOUNT-1, adults without diabetes lost an average of 15.0% of body weight on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg over 72 weeks, against 3.1% on placebo. Those are averages; individual results vary widely.
How much weight do people lose on Wegovy?
In STEP 1, adults without diabetes lost an average of 14.9% of body weight on 2.4 mg over 68 weeks, against 2.4% on placebo. In OASIS 4, the 25 mg Wegovy pill averaged 13.6% over 64 weeks, against 2.2% on placebo.
Is this calculator a prediction of my weight loss?
No. It applies a trial's published average to the starting weight you enter. Half the people in a trial lose less than the average and half lose more, and your prescriber sets your dose. Use it to compare medications and prices, not to set a goal.
Why does the calculator show placebo?
Everyone in these trials, including the placebo group, got diet and activity advice, and the placebo groups lost 2.1% to 3.1% of their weight. Showing it beside the drug's average is the only honest way to read the drug's share of the result.
What does a pound of weight loss cost on a GLP-1?
At the trial averages and today's prices, for a 220 lb start, the lowest cost per pound on this page is $33.68 (Wegovy, compounded semaglutide: snagrx). It depends on your weight, your dose and how long you stay on it.
Where these facts come from
We track prices. Every clinical and manufacturer claim about GLP-1 weight loss trials and prices on this page is quoted here in its source’s own words, with the date we read it. We do not write medical guidance and we do not tell anyone what dose to take.
8 sources · read Oct 3
- 01read Oct 3
we examined the safety and efficacy of once-daily orforglipron at doses of 6 mg, 12 mg, or 36 mg, as compared with placebo (assigned in a 3:3:3:4 ratio) as an adjunct to healthy diet and physical activity for 72 weeks. All the patients had obesity without diabetes mellitus. ... The mean change in body weight from baseline to week 72 was -7.5% (95% confidence interval [CI], -8.2 to -6.8) with 6 mg of orforglipron, -8.4% (95% CI, -9.1 to -7.7) with 12 mg of orforglipron, and -11.2% (95% CI, -12.0 to -10.4) with 36 mg of orforglipron, as compared with -2.1% (95% CI, -2.8 to -1.4) with placebo
ATTAIN-1, N Engl J Med 2025;393:1796-1806 (PubMed abstract) - 02read Oct 3
receive oral semaglutide (25 mg) or placebo once daily, plus lifestyle interventions. ... The estimated mean change in body weight from baseline to week 64 was -13.6% in the oral semaglutide group and -2.2% in the placebo group
OASIS 4, N Engl J Med 2025;393:1077-1087 (PubMed abstract) - 03read Oct 3
we enrolled 1961 adults with a body-mass index (the weight in kilograms divided by the square of the height in meters) of 30 or greater (≥27 in persons with ≥1 weight-related coexisting condition), who did not have diabetes, and randomly assigned them, in a 2:1 ratio, to 68 weeks of treatment with once-weekly subcutaneous semaglutide (at a dose of 2.4 mg) or placebo, plus lifestyle intervention. ... The mean change in body weight from baseline to week 68 was -14.9% in the semaglutide group as compared with -2.4% with placebo
STEP 1, N Engl J Med 2021;384:989-1002 (PubMed abstract) - 04read Oct 3
we assigned 2539 adults with a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 30 or more, or 27 or more and at least one weight-related complication, excluding diabetes, in a 1:1:1:1 ratio to receive once-weekly, subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 72 weeks, including a 20-week dose-escalation period. ... The mean percentage change in weight at week 72 was -15.0% (95% confidence interval [CI], -15.9 to -14.2) with 5-mg weekly doses of tirzepatide, -19.5% (95% CI, -20.4 to -18.5) with 10-mg doses, and -20.9% (95% CI, -21.8 to -19.9) with 15-mg doses and -3.1% (95% CI, -4.3 to -1.9) with placebo
SURMOUNT-1, N Engl J Med 2022;387:205-216 (PubMed abstract) - 05read Oct 3
Regular price for a 1-month supply of Zepbound single-patient-use KwikPen is $299 for 2.5 mg, $399 for 5 mg, $499 for 7.5 mg, $699 for 10 mg, $699 for 12.5 mg, and $699 for 15 mg.
Eli Lilly, Zepbound self-pay prices - 06read Oct 3
Patients new to the Wegovy Savings Offer or NovoCare Pharmacy pay $199 for each month of 0.25 mg & 0.5 mg. Offer for 2 monthly fills through December 31, 2026, then $349 per month for Wegovy 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, or 2.4 mg, and $399 per month for Wegovy HD (semaglutide) injection 7.2 mg.
Novo Nordisk, Wegovy self-pay prices - 07read Oct 2
Patients pay $149 for each month of 1.5 mg, $199 per month for 4 mg and $299 per month for 9 mg and 25 mg.
NovoCare Pharmacy, self-pay prices - 08read Oct 3
Regular price for a 1-month supply of Foundayo dosages is $149 for 0.8 mg, $199 for 2.5 mg, $299 for 5.5 mg and 9 mg, and $349 for 14.5 mg and 17.2 mg.
Eli Lilly, Foundayo self-pay prices