Why does weight loss stall on Wegovy, Ozempic or Zepbound?
What the long Canadian-reviewed trials show about when weight levels off, why the body pushes back, and what a doctor may look at next.
Written for Canada, from Canadian sources.
Weight loss on a GLP‑1 medicine slows and then levels off; that is expected. In long trials reviewed by Canada’s obesity guideline, average weight stopped falling after about 60 weeks on Wegovy and after 60 to 85 weeks on Zepbound, depending on the dose. The body also adapts to a lower weight.
Key takeaways
- In the 104-week STEP 5 trial, average weight on Wegovy 2.4 mg levelled off after about 60 weeks, at 15.2% below the start, and then held.1
- In SURMOUNT-1’s prediabetes group, average weight on Zepbound levelled off after about 60, 72 and 85 weeks on 5, 10 and 15 mg.1
- Canada’s obesity guideline says “our bodies are designed to resist weight loss”: resting energy use fell by about 15 calories a day for each kilogram lost.2
- The guideline notes that health can improve even when weight loss is small, so a plateau alone doesn’t mean a medicine has stopped helping.1
- People who stopped in withdrawal trials regained weight, 6.9% in STEP 4 and 14.0% in SURMOUNT-4, which suggests a plateau is not the same as the medicine stopping work.1
- GLP‑1 medicines are prescription drugs in Canada. Nothing here is a reason to start, stop or switch one.3
- We name brands and official prices as facts. We don’t recommend, rank or link to any brand, pharmacy, clinic or program.
- Canadian law bans advertising any drug to the general public as a treatment, preventative or cure for obesity or diabetes.4 This page is information, not an ad, and nothing here is for sale.
- Trial results are averages. Some people lose much less, and every benefit comes with risks: see our side effects guide.
On this page
Is a plateau normal on a GLP‑1 medicine?
Yes. In the long GLP‑1 trials that Canada’s obesity guideline summarises, average weight fell for about a year or more, then levelled off and held while people stayed on treatment.1
- Wegovy (semaglutide 2.4 mg), STEP 5: 304 people over 104 weeks lost 15.2% on average, against 2.6% on a dummy injection. Weight levelled off after about week 60.1
- Zepbound (tirzepatide), SURMOUNT-1: in 1,032 people with prediabetes followed for 176 weeks, weight fell 12.3%, 18.7% and 19.7% on 5, 10 and 15 mg, against 1.3%.1
- Saxenda (liraglutide 3 mg), SCALE: weight levelled off after about week 50.1
For someone starting at 90 kg (198 lb), 15.2% is about 14 kg (30 lb). These are averages: some people lose much more, and some very little. Ozempic’s trials were in type 2 diabetes and aimed at blood sugar, so they don’t tell us much about a weight plateau.5
- Stomach effects are very common (more than 1 in 10 people) on the EU Wegovy and Mounjaro labels. In Canada’s Wegovy monograph, 44 in 100 people on 2.4 mg felt sick (nausea), against 16 in 100 on a dummy injection; on Zepbound 15 mg it was 28 in 100, against 9 in 100.6,7,8,9
- Gallstones are common (up to 1 in 10) on the EU Wegovy label and uncommon (up to 1 in 100) on the EU Mounjaro label.6,7
- Pancreatitis (an inflamed pancreas) is uncommon (up to 1 in 100) on both: severe stomach pain that won’t go away, sometimes spreading to the back.6,7
- Thyroid and pregnancy. Not for anyone with a personal or family history of medullary thyroid cancer or MEN 2. Wegovy should stop at least 2 months before a planned pregnancy.8,9
Why does weight stop falling?
Your body adapts to a lower weight. The Canadian guideline’s science chapter says “our bodies are designed to resist weight loss”.2
- You burn less at rest. A review of 2,997 people found resting energy use fell by about 15 calories a day for each kilogram lost.2 For someone who has lost 14 kg, that is about 210 calories a day, by our arithmetic.
- Hunger signals shift. After diet-induced weight loss, hormones that curb appetite stay lower and the hunger hormone ghrelin stays higher, which “act to encourage weight regain”.2
The medicine keeps acting on appetite. A smaller body needs less energy, so at some point intake and use balance out. That point is the plateau.2,8
How is a good response judged?
Not by weight alone. The guideline notes that “substantial health improvements and goals of therapy may be realized regardless of the magnitude of weight loss”.1
The guideline notes that regulators have traditionally suggested stopping if weight loss is under 5% after 3 months on a full dose, then says health can improve whatever the amount lost.1 Public funding rules are stricter: Canada’s Drug Agency asks for at least 5% weight loss after the first year for coverage of Zepbound to continue.11
It says goals of treatment should be set for each person, and success judged against them.1
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What may a doctor look at when weight stops falling?
If goals aren’t being met, the guideline lists what to reassess: cost, access, whether the dose is adequate, taking it as prescribed, barriers to changing habits, and other medical or psychological issues.1
- The dose. The labels set the maintenance doses: 2.4 mg for Wegovy, and 5, 10 or 15 mg for Zepbound. Whether to change dose is the prescriber’s call.8,9
- Another treatment. The guideline says adding or substituting another obesity medicine or treatment can be considered if goals aren’t met on the highest dose a person tolerates.1
- Muscle and protein. A 2025 nutrition advisory notes that 1.2 to 1.6 g of protein per kg a day has been proposed during weight loss, along with strength training. If you have kidney disease, ask before raising protein.12
- Food and activity. The guideline treats medicines as an addition to nutrition and activity, not a replacement.1
- The approved use. Ozempic and Mounjaro are approved for type 2 diabetes, and the guideline discourages weight-only use of medicines that lack that approval or evidence-based recommendations.5,13,1
What happens if you stop because of a plateau?
Most people regain weight. In STEP 4, people switched from Wegovy to a dummy injection regained 6.9% of their weight in 48 weeks; in SURMOUNT-4, people switched from Zepbound regained 14.0% in 52 weeks.1
In both trials, the regain had not levelled off by the end.1 That suggests the medicine was still acting during the plateau. The guideline recommends long-term use when a medicine works.1 The full picture is in stopping a GLP‑1 in Canada and Guide 9: Stopping.
Questions people ask
Why have I stopped losing weight on Ozempic or Wegovy?
Weight loss levels off for most people. In STEP 5, average weight on Wegovy stopped falling after about 60 weeks; the body burns less and hunger signals shift after weight loss.1,2
How long does weight loss last on Wegovy or Zepbound?
In long trials, average weight fell for about 60 weeks on Wegovy and 60 to 85 weeks on Zepbound, then held while people stayed on treatment.1
Does a plateau mean the medicine has stopped working?
Not necessarily. People switched to a dummy injection in STEP 4 and SURMOUNT-4 regained weight, which suggests the medicine was still acting.1
Should I increase my dose if I plateau?
That is your prescriber’s decision. The Canadian labels set the maintenance doses: 2.4 mg for Wegovy and 5, 10 or 15 mg for Zepbound.8,9
How we researched this
We read the 2025 pharmacotherapy chapter and the science chapter of Canada’s adult obesity guideline, the Canadian monographs for Wegovy, Zepbound, Ozempic and Mounjaro, Canada’s Drug Agency’s 2026 Zepbound recommendation and a 2025 nutrition advisory, all checked on 14 October 2026.
Trial figures are as the guideline reports them. The calorie example is our arithmetic.
Before you move on
- Expect weight loss to slow and level off.
- Track more than weight: blood pressure, blood sugar, strength.
- Ask your prescriber before changing or stopping a dose.
- Keep up protein and strength training, and ask first if you have kidney disease.
- Know the warning signs in the risks box.
More from the Canada blog
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Sources
- Pedersen SD, Manjoo P, Dash S, et al. Canadian Adult Obesity Clinical Practice Guideline: Pharmacotherapy for Obesity Management in Adults, 2025 update. Obesity Canada, Version 3, 11 August 2025 (recommendations; six medicines approved for obesity in Canada; off-label use discouraged; trial summaries including when average weight plateaued; stopping and regain). PDF
- Lau DCW, Wharton S. Canadian Adult Obesity Clinical Practice Guidelines: The Science of Obesity. Obesity Canada, Version 1, 4 August 2020 (“our bodies are designed to resist weight loss”; resting energy expenditure fell by about 15 kcal per kg lost; appetite hormones after weight loss “act to encourage weight regain”). PDF
- Health Canada. Drug Product Database: product records, schedule, route and status for every semaglutide, tirzepatide, liraglutide and dulaglutide product (all on the “Prescription” schedule; all subcutaneous injections or oral tablets; for example Sevmia “Approved”, not marketed; first generic semaglutide marketed 6 May 2026). Searched 14 October 2026. Link
- Food and Drugs Act (R.S.C., 1985, c. F-27), section 3(1): “No person shall advertise any food, drug, cosmetic or device to the general public as a treatment, preventative or cure for any of the diseases … referred to in Schedule A.1”; Schedule A.1 lists diabetes and obesity. Justice Laws Website. Checked 14 October 2026. Link
- Novo Nordisk Canada. Ozempic (semaglutide injection) Product Monograph, 13 July 2026 (type 2 diabetes indications, including reducing the risk of major heart and blood-vessel events in adults with type 2 diabetes and heart or chronic kidney disease, and of kidney decline in type 2 diabetes with chronic kidney disease; GLP‑1 receptor agonist; 0.25 mg for 4 weeks, then 0.5 mg, then 1 mg and 2 mg if needed, maximum 2 mg; SUSTAIN 2 and SUSTAIN 9 results; Table 2 adverse reactions: nausea 17.0% on 0.5 mg and 19.9% on 1 mg vs 6.3% on comparators; once weekly “at any time of the day, with or without meals”; missed dose within 5 days; stop at least 2 months before a planned pregnancy; perioperative aspiration warning). PDF
- European Medicines Agency. Wegovy: EPAR product information (package leaflet section 4: nausea, vomiting, diarrhea, constipation and stomach pain “very common (may affect more than 1 in 10 people)”; gallstones “common”; acute pancreatitis “uncommon”). PDF
- European Medicines Agency. Mounjaro: EPAR product information (package leaflet section 4: nausea and diarrhea “very common (may affect more than 1 in 10 people)”; vomiting and constipation very common in people treated for weight management; acute pancreatitis and gallstones “uncommon (may affect up to 1 in 100 people)”). PDF
- Novo Nordisk Canada. Wegovy (semaglutide injection) Product Monograph, 2 October 2026 (indications; dose escalation 0.25, 0.5, 1, 1.7 mg every 4 weeks to 2.4 mg; reassess after 12 weeks on the maintenance dose; STEP 1–3 results; Table 4: nausea 44% vs 16% on placebo; perioperative aspiration warning). PDF
- Eli Lilly Canada. Zepbound (tirzepatide injection) Product Monograph, 11 June 2026 (indications; 2.5 mg start, maintenance 5, 10 or 15 mg; “The ZEPBOUND multi-dose KwikPen contains 4 doses”; SURMOUNT-1 results; Table 2: nausea 28.0% on 15 mg vs 8.5% on placebo; not to be combined with other tirzepatide or GLP‑1 products; aspiration warning). PDF
- Heart and Stroke Foundation of Canada. Medical services by phone (811 in most provinces and Yukon; Info-Santé 811 in Quebec). Checked 12 October 2026. Link
- Canada’s Drug Agency (CDA-AMC). Tirzepatide (Zepbound) reimbursement recommendation SR0920, committee meeting 24 June 2026: “Reimburse with conditions” only for adults with a BMI of 27 or more and prediabetes, if the cost is reduced; submitted price $300.00 per 2.5 or 5 mg pen, $420.00 per 7.5 or 10 mg pen and $540.00 per 12.5 or 15 mg pen (“12 mg” in the source), annual cost $3,913 to $7,044. Link
- Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. Am J Clin Nutr 2025;122:344–367 (“Higher targets, such as 1.2–1.6 g/kg/d, have also been proposed during active weight reduction”; preserving muscle through resistance training). PMC
- Eli Lilly Canada. Mounjaro (tirzepatide injection) Product Monograph, 23 June 2026 (type 2 diabetes in adults and ages 10 to under 18; “a GIP and a GLP-1 receptor agonist”; dose steps; oral hormonal contraceptives: switch to a non-oral method or add a barrier method for 4 weeks after starting and after each dose increase; SURPASS-2 Table 10; Table 2 adverse reactions: nausea 12.2%, 15.4% and 18.3% on 5, 10 and 15 mg vs 4.3% on placebo; aspiration warning). PDF
Last checked 14 Oct 2026 · Next review due 14 Oct 2027 · Report an error
How this page was made. Written by the GLP Guidebook team from the sources above. Prices are official list, formulary or maker-submitted prices, never a pharmacy, clinic, savings-card or coupon price. Figures marked as our arithmetic are worked out from those sources. It’s general information, not medical advice, and not an advertisement for any medicine. Talk to your family doctor, nurse practitioner or pharmacist before starting, stopping or changing any medicine. We don’t sell, prescribe or recommend any brand or provider. How we write