Weight loss on a GLP-1 drug is fast at first, then slows, then levels off. That is not a sign the drug stopped working. It is what the average curve looked like in both of the big trials covered here. In STEP 1, average weight on semaglutide stopped falling at around week 60. In SURMOUNT-1, the tirzepatide curves were nearly flat between weeks 60 and 72. This guide walks through those curves, how dose changes where the curve flattens, what the labels say about maintenance doses, and why the body pushes back.
A plateau here means your weight stops going down for weeks at a time while you keep taking the same dose. Daily weigh-ins bounce around, so one flat week does not count. The trials looked at averages over many months, which smooths out that noise.
One thing to know before reading the numbers: trial results come in two flavors. The headline numbers (for example, -14.9% in STEP 1) are statistical estimates that include people who stopped the drug. The curves in the labels show the observed average of people who came to each visit. The observed numbers usually look a little better. Both are below.
STEP 1 gave 1,961 adults weekly semaglutide 2.4 mg or placebo for 68 weeks, plus diet and activity advice. The dose was raised over 16 weeks, then held for 52 weeks. The headline result was -14.9% with semaglutide and -2.4% with placebo (Wilding et al., NEJM 2021; Wegovy label, 14.2, Study 2).
The Wegovy label shows the observed curve for this trial (Study 2) in Figure 7. The chart prints the week-68 values:
| Week | Semaglutide 2.4 mg (observed mean) | Placebo (observed mean) |
|---|---|---|
| 68 | -15.6% | -2.8% |
The curve itself shows the shape. Most of the loss happened in the first 36 weeks. Between week 52 and week 68 the average barely moved, with the low point around week 60. The dose was the same 2.4 mg the whole time after week 16.
Even at the end, people varied a lot. In STEP 1, 86.4% lost at least 5%, 69.1% lost at least 10%, and 50.5% lost at least 15% (Wilding et al., NEJM 2021). So about half of people leveled off below a 15% loss.
SURMOUNT-1 gave 2,539 adults weekly tirzepatide 5 mg, 10 mg or 15 mg, or placebo, for 72 weeks, including a dose-escalation period of up to 20 weeks (Jastreboff et al., NEJM 2022). Figure 3 in the Zepbound label shows the observed curves (Zepbound label, 14.1). The chart prints the week-72 values:
| Week | 5 mg | 10 mg | 15 mg | Placebo |
|---|---|---|---|---|
| 72 | -16.1% | -20.9% | -22.0% | -3.3% |
Each dose curve bends the same way. Weight fell fast through about week 36, then more slowly, and changed very little between week 60 and week 72. The 5 mg curve was the first to flatten and flattened at the highest weight. The 10 mg and 15 mg curves kept going a little longer and leveled off lower.
So a higher dose did not remove the plateau. It moved it.
The headline 72-week results from SURMOUNT-1 show the dose effect. These are the treatment estimates that count people who stopped the drug (Jastreboff et al., NEJM 2022; Zepbound label, 14.1, Table 2):
| SURMOUNT-1 arm (72 weeks) | Mean weight change | Lost 10% or more | Lost 20% or more |
|---|---|---|---|
| Tirzepatide 5 mg | -15.0% | 68.5% | 30.0% |
| Tirzepatide 10 mg | -19.5% | 78.1% | 50.1% |
| Tirzepatide 15 mg | -20.9% | 83.5% | 56.7% |
| Placebo | -3.1% | 18.8% | 3.1% |
The step from 5 mg to 10 mg was larger than the step from 10 mg to 15 mg. Even on 15 mg, about 1 in 6 people did not reach a 10% loss, so individual plateaus vary a lot.
Semaglutide now has a similar story. In the 72-week Study 8 in the Wegovy label, 7.2 mg weekly produced -18.8%, 2.4 mg produced -15.5%, and placebo -3.9%. The difference between 7.2 mg and 2.4 mg was -3.3 percentage points (Wegovy label, 14.2, Table 12).
These are fixed-dose trials, where people were assigned a dose and kept it. They do not tell you what happens if one person moves up a dose after leveling off. For that, the labels are the guide.
Zepbound (tirzepatide). The label starts at 2.5 mg weekly for 4 weeks and says that dose is for starting only, not for maintenance. After that, the dose may be raised in 2.5 mg steps after at least 4 weeks on the current dose. The maintenance dose for weight reduction is 5 mg, 10 mg or 15 mg weekly, and 15 mg is the maximum. The label says to consider treatment response and tolerability when choosing the maintenance dose, and to consider a lower one if a dose is not tolerated (Zepbound label, 2.1 and 2.2).
Wegovy (semaglutide injection). The label raises the dose every 4 weeks from 0.25 mg to 1.7 mg, with maintenance from week 17. For adults, the maintenance dose for weight reduction is 1.7 mg or 2.4 mg (recommended). For people who tolerate 2.4 mg for at least 4 weeks and need more weight reduction, the dose may be increased to a maximum of 7.2 mg weekly. It also says to weigh treatment response and tolerability (Wegovy label, 2.2).
Notice the wording: "treatment response" is one of the things your prescriber weighs. A plateau is a reasonable thing to raise with them. Whether a dose change makes sense depends on your side effects, your health goals and the label for your exact drug. That is their call to make with you, not a decision to make from a trial chart. For unit conversions on compounded vials, see the tirzepatide and semaglutide unit charts.
Losing weight sets off responses that work against further loss. This is normal biology, and it happens with diets too. Three studies show it, though none of them tested a GLP-1 drug.
A GLP-1 drug lowers appetite, which lets weight fall a long way. As weight falls, these pushback signals grow. At some point the two balance and weight holds steady. That balance point is the plateau. That would explain why higher doses in the trials leveled off at a lower weight rather than not leveling off at all.
A plateau on the drug and stopping the drug are very different. In Study 5 in the Wegovy label, people who reached the full 2.4 mg dose during a 20-week run-in were randomly assigned, 2 to 1, to keep taking it or to switch to placebo without knowing which they got. By week 68, the observed average was -17.7% for those who stayed on the drug and -5.4% for those switched to placebo (Wegovy label, 14.2, Figure 8). Holding steady on the drug kept most of the loss. Our companion post on stopping a GLP-1 and weight regain covers that side in detail.
If your weight has been flat for a while, the useful questions are about your record, not about willpower. Before the visit, gather:
Dose Track keeps that record for you. You log each shot, and it tracks dose changes, missed doses, weigh-ins and side effects, along with vials, supplies and reminders. That makes the conversation about facts. See the GLP-1 tracking guide and how weight tracking works.
If you are also concerned about what kind of weight you are losing, read our post on GLP-1s and lean mass loss. For background on the drugs, see the tirzepatide and semaglutide pages, the semaglutide vs tirzepatide comparison, and the glossary entry for titration.
This article is general information, not medical advice. Talk to your prescriber before you start, change or stop any medicine.