When does weight loss slow down on Wegovy and Zepbound, and is my stall normal?

Does the plateau depend on the dose?

Yes: the higher tirzepatide doses kept falling longer. In SURMOUNT-1 the mean loss at 72 weeks was 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg, and the 5 mg curve was essentially flat from week 52. STEP 1 reached the 2.4 mg maintenance dose at week 16, so before that a slow curve reflects titration, not a plateau.

Dose stage matters more than calendar week. Trial curves are labelled by the maintenance dose, but participants spent the first weeks stepping up to it. At week 10 on a starter dose, you are not yet on the dose the curve is named after.

Why does the scale stop when the average curve is still falling?

Because a mean curve is smoother than any one person. Averaging hundreds of participants turns staircases into a slope; individual weight moves in steps, and water, sodium, glycogen, constipation and menstrual-cycle phase each move the scale a pound or more. That is why the trials weighed people at set clinic visits rather than daily.

There is no published average plateau length. STEP 1 and SURMOUNT-1 report group means at fixed visits, not how long individuals sat flat, so any site quoting a typical stall length in weeks is not reading it from the trials.

When should I talk to my prescriber about a stall?

Whenever a stall worries you. The trials give no waiting period that applies to everyone, so there is no number of flat weeks you have to sit through first; raise it at your next visit, and sooner if your weight is going back up or side effects are making it hard to eat or drink. Take logged weights, not a feeling that it stopped working. Do not change or stop a dose because of a calculator, this one included.

Regain after stopping is a different question from a stall: in the STEP 1 extension, participants regained two-thirds of their lost weight in the year after semaglutide was withdrawn (Wilding et al., 2022). The weekly tracker keeps your line next to the trial line so a stall is measured against a record.

If the stall has you weighing whether the monthly bill is still worth it, GLP-1 cost by route lists every route's one-year total and cost per pound; if the problem is a coverage refusal rather than the scale, see what to do when insurance won't cover Wegovy or Zepbound.

Where do these numbers come from?

• STEP 1: Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity. NEJM 2021;384:989-1002. doi:10.1056/NEJMoa2032183. Mean −14.9% at 68 weeks, placebo −2.4%; titration to 2.4 mg by week 16. The mean curve at every reported timepoint is on the curve calculator and in trials.json. Derived rates on this page: 0.5%/wk is the loss over the first three months divided by the weeks; 0.2%/wk is the week 20 to week 36 difference (3.5% of body weight) divided by 16 weeks.
• SURMOUNT-1: Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity. NEJM 2022;387:205-216. doi:10.1056/NEJMoa2206038. Mean at 72 weeks: −15.0% (5 mg), −19.5% (10 mg), −20.9% (15 mg). Derived: 0.63%/wk is the loss over the first three months divided by the weeks; 3.0 points over weeks 20–28 and 2.5 points over weeks 28–36 are differences between the reported timepoints, which are on the curve calculator.
• STEP 1 extension: Wilding JPH et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide. Diabetes Obes Metab 2022;24:1553-1564. doi:10.1111/dom.14725. Two-thirds of lost weight regained one year after withdrawal.
• Per-block rates in the table above are the differences between published timepoints divided by the weeks between them; between timepoints the curve is interpolated linearly. The full curve table is trials.json (CC BY 4.0); see methods.