Weight Loss Plateau on Ozempic or Zepbound — Why It Happens

For months the scale went one way. Then, sometime around the fifth or sixth month, it stopped. Three Mondays in a row, the same number, give or take a few tenths. You haven't changed anything, and you start to wonder whether the medication has quietly stopped working.

It's one of the most common worries on a GLP-1, and it's usually less alarming than it feels. Weight loss on these medications was never a straight line, even in the trials.

What does weight loss look like over time in the trials?

A curve that starts steep and gradually flattens. In STEP 1, the main trial of semaglutide 2.4 mg (the dose in Wegovy), people lost weight from the first check at week 4, and average weight loss reached its lowest point at week 60. By the end of the 68-week trial, the average change was −14.9%, against −2.4% on placebo.

SURMOUNT-1, the main trial of tirzepatide (Zepbound), ran for 72 weeks, including 20 weeks of dose steps. Average weight change at week 72 ranged from −15.0% to −20.9% depending on dose, against −3.1% on placebo.

Trial	Medication	Length	Average change at the end	Placebo
STEP 1	Semaglutide 2.4 mg	68 weeks	−14.9%	−2.4%
SURMOUNT-1	Tirzepatide 5–15 mg	72 weeks	−15.0% to −20.9%	−3.1%

These are averages from different trials with different people. They aren't a target, and they aren't a forecast for you. If you'd like a rough sense of your own pace, our weight loss timeline calculator can help frame the conversation.

When do individual people tend to plateau?

Earlier than the averages suggest, and at very different times. A 2025 analysis of tirzepatide trial data defined a plateau as less than 5% weight change over 12 weeks and every 12 weeks after. Looking at people who took their medication as planned and lost at least 5%, the typical (median) person in SURMOUNT-1 plateaued at about 24 weeks if they started with overweight, about 26 weeks with class I obesity, and about 36 weeks with class II or III obesity. Close to 9 in 10 had reached a plateau by week 72.

The authors make a point worth repeating: a plateau is easy to mistake for the medication losing its effect. They describe it instead as the body moving from losing weight to holding a new, lower weight, the start of what ideally becomes long-term maintenance. They also note there's no agreed definition of a plateau, and that these findings are exploratory.

Why does weight loss slow down?

Because your body pushes back as you lose weight. Researchers Kevin Hall and Scott Kahan estimate that for every kilogram lost, the calories your body burns each day fall by about 20–30, while appetite rises by about 100 calories a day. That second part, the appetite response, is the bigger driver.

A smaller body also simply needs less energy to run. Put together, the gap between what you eat and what you burn narrows until the two meet. A GLP-1 helps by quieting appetite, but the same biology still applies, which is why the curve bends.

Is it really a plateau, or just a noisy week?

Often it's the second. The tirzepatide analysis notes that day-to-day weight changes of about 1–2% are normal fluctuation. Salt, a late meal, constipation, hormones, a hard workout or a long flight can all show up on the scale for a few days.

That's why a single weigh-in tells you very little. A weekly average smooths out the noise. If the average is still drifting down, even slowly, you're not on a plateau. If it's been flat for several weeks, that's real information.

It's also worth looking past the scale. If you're strength training and eating enough protein, your clothes may fit differently while your weight barely moves. Our page on GLP-1 muscle loss explains why holding on to lean mass matters, and the 2025 joint nutrition advisory pairs GLP-1 treatment with regular resistance training and adequate protein.

When should I talk to my prescriber?

Any time a stall worries you, and especially if:

• Your weekly average has been flat for several weeks and you want to understand why.
• You're regaining weight steadily rather than holding.
• You're struggling to eat enough, or side effects make meals hard.
• You're thinking about stopping or changing your medication.

On that last point: in the STEP 1 extension, people who stopped semaglutide regained about two-thirds of the weight they had lost within a year. That's not a reason to stay on anything without question. It's a reason to make any change with your prescriber, not alone. Decisions about your dose belong in that conversation too.

What we'd track

1. Weekly average weight. Weigh in the same way at the same time, then judge by the weekly average, not the daily number.
2. Protein. It helps protect muscle, and on low-appetite days it's often the first thing to slip.
3. Strength sessions. A heavier weight or a few more reps is progress the scale can't see.
4. Waist or clothing fit. A tape measure once a month, or one pair of jeans, written in your notes.
5. Dose days and side effects. A stall that lines up with a rough patch of nausea or fatigue tells a different story.

Holt shows your weight as a weekly average and as a chart over 7 days, 30 days, 90 days or a year, along with your percent to goal. Meal photos estimate protein, Apple Health brings in your workouts and weigh-ins, and side effects sit against your dose days on one timeline.

See your weekly average, not just today's number, in Holt

Before your next appointment, the Doctor Visit Report turns your trend, doses and side effects into one PDF with suggested questions to ask. For a wider look at measuring progress, see our GLP-1 progress tracker page.