Ozempic®, a new treatment for type 2 diabetes (part of the GLP-1 agonists), is being prescribed more and more regularly. In fact, its indications have also been extended to the management of obesity and overweight.
GLP-1 is a digestive hormone that increases satiety and helps regulate blood sugar. People suffering from obesity often secrete less of it after meals. Treatments such as Ozempic® mimic this hormone and provide a more stable and long-lasting effect, which explains their weekly administration (one injection per week).
Drawn by promises of rapid weight loss, many patients are unaware that the beginning of treatment with Ozempic® often comes with digestive effects. These are sometimes very pronounced.
This is absolutely normal: these mechanisms are closely linked to the very action of GLP-1 on the stomach and satiety.
If you are about to start or have just started this treatment, and if you have questions about its side effects, you’re in the right place! I’ll review these effects, how long they last, and give you my tips on how to manage them as well as possible.
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Most frequently encountered adverse effects during treatment with Ozempic®
Starting the treatment: a key step
The treatment consists of one injection per week with a pre‑filled pen in the abdomen, the top of the thigh, or the upper arm.
The patient starts with the lowest dose, which is generally increased after the first 4 weeks of treatment, then increased again after another 4 weeks of treatment if your doctor deems it necessary.
The most common effects: digestive effects
The most frequently encountered side effects at the beginning of taking Ozempic® are mainly gastrointestinal and in particular a very frequent occurrence according to the package leaflet of nausea and diarrhea, and a frequent occurrence of vomiting, abdominal pain and bloating, constipation, reflux, and flatulence.
Some people also notice a very significant decrease in appetite with a strong feeling of fullness.
These effects usually appear when starting the treatment, or after an increase in the dose. They should be temporary and gradually diminish in the month following the start of the treatment or the dosage increase.
Non-digestive effects frequently observed
There are also frequently dizziness, headaches, and fatigue. These symptoms appear mainly at the beginning of the treatment, while the body adapts.
They are often linked to a decrease in appetite, insufficient hydration, or variations in blood sugar levels. In most cases, they are temporary and lessen once the dose is stabilized.
Infrequent but closely monitored side effects
Other uncommon to rare side effects may occur: acute pancreatitis, severe allergic reaction, eye disorder, intestinal obstruction.
It is advisable to consult your doctor in case of:
- persistent pain in the stomach or back
- changes in vision
- breathing problems, swelling of the face, lips, tongue and/or throat, with difficulty swallowing and an increased heart rate
- severe constipation associated with other digestive symptoms such as stomach pain, bloating, vomiting
But don’t worry! According to this literature review, most of these new treatments are safe, and those based on semaglutide such as Ozempic® are among the safest.
In any case, I recommend that you consult your doctor if you feel the need to.
My tips for managing the adverse effects of Ozempic® (and other GLP-1 agonists)
Here are my dietitian’s tips to help you better cope with the side effects that may occur when starting treatment or when the dose is increased:
- Carefully follow the medical recommendations and gradually increase the treatment dose
- Split meals: plan smaller quantities, even if it means eating more frequently
- Avoid foods that are too fatty and too sugary that can worsen nausea, and favor meals that are eaten cold, with little odor, if necessary
- Stay well hydrated between meals, especially in case of vomiting or diarrhea
- Chew well to make digestion easier.
- Do not hesitate to use the prescribed anti‑nausea medications if the discomfort caused by the treatment is too great
- Rely on the medical advice of your prescriber, who will be able to reassess your treatment
Sources and scientific studies
Summary of product characteristics and Ozempic instructions for use
McGowan B, Ciudin A, Baker JL, Busetto L, Dicker D, Frühbeck G, Goossens GH, Monami M, Sbraccia P, Martinez-Tellez B, Woodward E, Yumuk V. 2025. A systematic review and meta-analysis of the efficacy and safety of pharmacological treatments for obesity in adults
