Does hunger returning mean the medicine has stopped working?
“I took my last 0.5 mg dose of Ozempic on Sunday. I feel hungry again — can I have my next injection already?” This question comes up when reduced appetite becomes the main measure of how well the medicine is working. However, feeling hungry alone does not mean that the dose is no longer working. [199] [200]
Semaglutide, the active ingredient in Ozempic, remains in the body for many days. Its half-life is about a week: this is how long it takes for the amount of medicine in the body to fall by roughly half. This does not mean that it disappears after seven days or that it works “half as well”. With regular dosing, each new dose adds to the medicine remaining from previous doses. [200]
Ozempic is used to treat type 2 diabetes. Assessment includes blood sugar control and how well treatment is tolerated, rather than just whether the patient feels like eating. [198]
What did the appetite studies actually investigate?
A small study from 2017 involved 30 adults with obesity. Over 12 weeks, researchers assessed hunger, food cravings and the amount of food eaten, among other things. People taking Semaglutide showed reduced appetite and improved control over eating. The dose was gradually increased to 1 mg weekly. [199]
This study shows the medicine’s effect on appetite, but does not establish the day on which a 0.5 mg dose “stops working”. It did not test a regimen of “I take an extra injection when I am hungry”. The study findings therefore cannot be turned into such a rule. The study was funded by the manufacturer of Semaglutide; this is worth considering alongside the small number of participants. [199]
What are the risks of taking extra injections?
Shortening the intervals between doses increases the amount of medicine taken. It may worsen nausea, vomiting and diarrhoea. Fluid loss can lead to dehydration and worsening kidney function. The risk of low blood sugar is particularly important when insulin or sulfonylureas are also being used. [198]
Severe, persistent abdominal pain requires urgent medical assessment. Persistent vomiting and an inability to replace lost fluids also require help. These are not signs that weight loss is “going well”. [198]
Why is the aim not to stop eating altogether?
A reduced appetite can make it easier to eat appropriate portions. However, the body still needs protein, energy, vitamins and minerals. Aiming to eat nothing all day is not a sensible treatment goal. [201]
A joint position statement issued by four scientific societies in 2025 highlighted nutritional deficiencies and muscle loss during obesity treatment with medicines that act on GLP-1. It emphasised the importance of adequate nutrition and strengthening exercises. A fall in the number on the scales does not tell the whole story about the quality of treatment. [201]
Can you change the day of your injection?
Ozempic is given once a week. The official information allows the injection day to be changed if the time between injections is more than 72 hours. Weekly injections then continue on the new day. This allows the scheduled day to be changed; it does not authorise ongoing dosing every few days. [198]
Do not take an extra dose because of your appetite. Discuss any dose change or recurring problems with how the medicine is working with the person managing your treatment. [198]
What should you do if your appetite regularly returns?
Before discussing your treatment, it is worth noting when hunger occurs, what your meals are like, whether you have side effects and what your blood sugar readings are, if you take them. This description is more useful than simply concluding that “the medicine no longer works”.
If sudden hunger occurs alongside trembling, sweating, palpitations or weakness, it may indicate low blood sugar. Check your blood sugar if you can, and follow your agreed plan for treating low blood sugar. An extra dose of Ozempic is not a treatment for it. [202]
You can read more about this substance and the medicines that contain it in separate semaglutide profile.
Where does this information come from?
Show sources and how they were checked
- Ozempic: Product information
European Medicines Agency · sections 4.1, 4.2, 4.4, 4.8, 4.9 and 5.2 of the summary of product characteristics consulted. Accessed: 14.11.2026.
- Effects of once-weekly semaglutide on appetite, energy intake, control of eating, food preference and body weight in subjects with obesity
Blundell et al. · Diabetes, Obesity and Metabolism, 2017 · full text consulted · study funded by Novo Nordisk; some authors were company employees · DOI: 10.1111/dom.12932. Accessed: 14.11.2026.
- A Randomized Trial Investigating the Pharmacokinetics, Pharmacodynamics, and Safety of Subcutaneous Semaglutide Once-Weekly in Healthy Male Japanese and Caucasian Subjects
Clinical Pharmacokinetics, 2018 · full text consulted · a study in healthy men, not a study of changing dosing without medical guidance. Accessed: 14.11.2026.
- Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory
American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, The Obesity Society · 2025 · PubMed abstract consulted · a position statement on nutrition, not a dosing study. Accessed: 14.11.2026.
- Low blood sugar (hypoglycaemia)
NHS · patient information page consulted: symptoms and management of low blood sugar. Accessed: 14.11.2026.