What does “not working” actually mean?
The first injection, a few days of waiting and then disappointment: your appetite is still there, and your weight has barely changed. Or the reverse — at first, you lost interest in food, but after a few months, hunger returned. Does this mean the medicine is not working?
Appetite alone is not enough to assess how effective treatment is. The dose, how long you have been taking it, changes in body weight and glucose results also matter. The aim of treatment is to improve health and control the condition. Losing all desire to eat is not a requirement for treatment to succeed. [201] [206]
This article covers injections used in adults. Dosing information was checked on 14 November 2026.
Three medicines, different approved uses and doses
Ozempic contains Semaglutide and is approved for treating type 2 diabetes. Weight loss may occur during treatment, but its effectiveness should not be assessed solely in terms of kilograms. [201]
Wegovy also contains Semaglutide, but is intended for treating obesity or overweight with certain health problems. [202]
Mounjaro contains a different substance — Tirzepatide — and is indicated for both the treatment of type 2 diabetes and weight management in patients who meet the eligibility criteria. Doses of these medicines cannot be converted milligram for milligram. [203]
When does it start working?
There is no single specific day when treatment starts working. Blood glucose reduction, feelings of fullness and weight loss happen at different rates. Semaglutide may lower fasting blood glucose after the very first dose. However, its concentration only stabilises after around 4–5 weeks of regularly taking the same dose. This does not mean that it is inactive during the first month or that maximum weight loss is achieved after a month. [201]
For Tirzepatide, the concentration stabilises after around four weeks of weekly dosing. [203]
Feelings of hunger vary more from person to person. In a small study of Tirzepatide, reduced appetite and greater fullness were recorded as early as the assessment in the third week. However, this does not mean that every patient must feel a clear change by that point. The study shows that the medicine may work early on; it does not establish a personal date when it will “kick in”. [204]
Why start with a low dose?
Low starting doses help the body get used to treatment. Gradually increasing the dose reduces gastrointestinal symptoms. A lack of a clear change in appetite at the start is not a reason to skip the next stages. The schedules below describe dosing in the medicines' product information; moving to the next dose depends on the effects and how well treatment is tolerated. [201] [202] [203]
Ozempic: starting at 0.25 mg once a week
| Stage | Dose |
|---|---|
| First 4 weeks | 0.25 mg once a week |
| Then | 0.5 mg once a week |
| If better diabetes control is needed | 1 mg after at least 4 weeks of taking 0.5 mg |
| If still needed | 2 mg after at least 4 weeks of taking 1 mg |
The 0.25 mg dose is a starting dose, not a maintenance dose. The maximum recommended dose is 2 mg per week. Increasing the dose is not automatically required with each new pack. [201]
Wegovy: gradual dose increases over the first 16 weeks
| Week of treatment | Once-weekly dose |
|---|---|
| 1–4 | 0.25 mg |
| 5–8 | 0.5 mg |
| 9–12 | 1 mg |
| 13–16 | 1.7 mg |
| From week 17 | 2.4 mg |
Current EU product information also allows the dose to be increased to 7.2 mg weekly, after at least four weeks on 2.4 mg, in adults with a BMI of at least 30 at the start of treatment. This is an option for certain patients, not another mandatory step. If the higher dose does not lead to additional improvement in body weight, the product information recommends returning to 2.4 mg. Dose increases may be delayed if side effects are significant. [202]
Mounjaro: starting at 2.5 mg once a week
After four weeks, the dose is increased to 5 mg. Further increases, if needed, are made in 2.5 mg steps after at least four weeks on the current dose. [203]
The subsequent available dose levels are 5 → 7.5 → 10 → 12.5 → 15 mg weekly. The recommended maintenance doses for adults are 5, 10 or 15 mg, and the maximum dose is 15 mg. Not everyone needs to reach the maximum. [203]
Does a slower start determine the outcome?
An analysis of the SURMOUNT-1 trial assessed people taking tirzepatide who, after 12 weeks, had lost less than 5% of their initial body weight. Around 90% of these participants achieved at least that amount of weight loss by week 72. [205]
This finding concerned a selected group of participants who took their treatment regularly and did not have type 2 diabetes. It does not guarantee an outcome for every patient, but it shows why an assessment after just the first few injections may be premature. [205]
Appetite returning and no nausea
A returning appetite is worth assessing alongside how much we actually eat. It is possible to feel hungry again while still finishing meals sooner, choosing smaller portions and snacking less often. Semaglutide studies assess these different aspects: hunger, fullness, control of eating and energy intake. A single feeling does not describe the full effect of treatment. [206]
Similarly, not feeling nauseous does not mean the medicine is not working. Analyses of the STEP trials found that weight loss with semaglutide also occurred in people without gastrointestinal side effects. Nausea and vomiting are side effects, not a measure of whether the dose is right. [207]
What does it mean when weight loss stops?
A pause in weight loss does not necessarily mean the medicine has stopped working either. Weight often stabilises after a period of weight loss. This was also observed in tirzepatide trials. Maintaining a lower body weight can be an important treatment outcome. A different assessment is needed if body weight is steadily increasing or diabetes control is worsening. [208]
What should you prepare for a discussion about treatment?
Before an appointment, it is worth noting a few specific details:
- your current dose and the number of weeks you have been taking it;
- missed doses or longer breaks;
- weight measurements taken under similar conditions over successive weeks;
- changes in portion sizes, snacking and drinks that contain calories;
- side effects and any other medicines you take;
- if you have diabetes — glucose readings and your latest HbA1c result.
HbA1c reflects your average glucose level over roughly three months. A single glucose reading and your current appetite therefore cannot replace an assessment of the treatment as a whole. [209]
If the expected results are not appearing, treatment needs reviewing — not extra injections. A doctor can check your injection technique, how regularly you take the medicine, the dose, other possible reasons for difficulties, and whether a change in treatment is appropriate. You do not need to wait until your next scheduled review if glucose levels are clearly rising or concerning symptoms appear.
Returning hunger is not a reason to take an extra dose. Bringing injections forward or increasing the dose yourself can worsen nausea, vomiting and dehydration. Severe, persistent abdominal pain, especially if it spreads to the back, requires urgent assessment; if pancreatitis is suspected, do not take another dose until the situation has been clarified. [210]
Also read the separate profiles of semaglutide and tirzepatide.
Where does this information come from?
Show sources and how they were checked
- Ozempic 0.5 mg solution for injection in pre-filled pen — Summary of Product Characteristics
Novo Nordisk · product information on emc · indications, dosage, onset of the effect on blood glucose, and pharmacokinetics. Accessed: 14.11.2026.
- Wegovy: Product information
European Medicines Agency · sections 4.1 and 4.2 reviewed · adult dosage, including the conditions for an increase to 7.2 mg. Accessed: 14.11.2026.
- Mounjaro: Product information
European Medicines Agency · sections 4.1, 4.2 and 5.2 reviewed · indications, adult doses and pharmacokinetics. Accessed: 14.11.2026.
- Tirzepatide on ingestive behavior in adults with overweight or obesity: a randomized 6-week phase 1 trial
Nature Medicine, 2025 · phase I trial · description of the appetite assessment in the third week reviewed; it does not establish when an individual will first notice an effect · DOI: 10.1038/s41591-025-03774-9. Accessed: 14.11.2026.
- Weight reduction over time in tirzepatide-treated participants by early weight loss response: Post hoc analysis in SURMOUNT-1
Diabetes, Obesity and Metabolism, 2025 · abstract and group selection criteria in the publisher's article reviewed · analysis performed after the trial, in people without type 2 diabetes · DOI: 10.1111/dom.16554. Accessed: 14.11.2026.
- The effect of semaglutide 2.4 mg once weekly on energy intake, appetite, control of eating, and gastric emptying in adults with obesity
Diabetes, Obesity and Metabolism, 2021 · description of appetite measurements and results reviewed; taking an extra dose when hunger returns was not studied · DOI: 10.1111/dom.14280. Accessed: 14.11.2026.
- Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss
Diabetes, Obesity and Metabolism, 2022 · abstract reviewed · analysis of the relationship between gastrointestinal side effects and weight change in the STEP trials · DOI: 10.1111/dom.14551. Accessed: 14.11.2026.
- Time to weight plateau with tirzepatide treatment in the SURMOUNT-1 and SURMOUNT-4 clinical trials
Clinical Obesity, 2025 · abstract reviewed · analysis of weight stabilisation in people with overweight or obesity without type 2 diabetes · DOI: 10.1111/cob.12734. Accessed: 14.11.2026.
- The A1C Test & Diabetes
National Institute of Diabetes and Digestive and Kidney Diseases · information on the period reflected by an HbA1c test. Accessed: 14.11.2026.
- Ozempic 0.5 mg solution for injection in pre-filled pen — Patient Information Leaflet
Novo Nordisk · patient leaflet on emc · dosage and symptoms requiring urgent assessment. Accessed: 14.11.2026.