Medically reviewed by Dr. Meinolf Dorka, Medical Director, last reviewed September 2026
Perhaps you have been reading about weight loss injections for some time. Some accounts describe them as a turning point, others lead with side effects, and somewhere between the two sits the question that matters to you: are they safe for someone like me?
Wanting a clear answer before taking a step is not hesitation. It is a reasonable way to approach a medicine that is used over months, and often longer.
The short answer
Weight loss injections authorised in Switzerland have a well-described safety profile when they are prescribed for the right person and monitored by a physician. The most common side effects affect digestion, such as nausea, diarrhoea or constipation, and they tend to appear when treatment starts or the dose is increased.
Serious side effects are uncommon but real, and some people should not use these medicines at all. Products bought without a prescription from unknown sources carry separate risks, because their contents cannot be verified.
When to seek urgent medical help
Call 144, or go to an emergency department, if you are using one of these medicines and you notice:
-severe stomach pain that does not go away, which may spread to your back, with or without vomiting;
-signs of a severe allergic reaction, such as swelling of the face, lips, tongue or throat, or difficulty breathing or swallowing;
-signs of severe low blood sugar, such as confusion, shaking, sweating or fainting, particularly if you also take insulin or a sulfonylurea.
ahtida Health is not an emergency service.
What are weight loss injections?
In plain terms, they are medicines injected under the skin that act like a hormone your gut releases after a meal. That hormone, GLP-1, helps signal fullness, slows how quickly the stomach empties and helps regulate blood sugar. Medicines that copy its action are called GLP-1 receptor agonists.
Their effect on fullness reduces appetite and food intake, which is why they are used in weight management as well as in type 2 diabetes. They are meant to be one part of a plan that also includes healthy eating, activity and changes in behaviour.
Three substances are authorised by Swissmedic for weight regulation in adults: semaglutide and tirzepatide, each injected once a week, and liraglutide, injected once a day. Tirzepatide acts on the receptor for a second gut hormone, GIP, as well as on the GLP-1 receptor. All three are prescription-only, and all are intended to be used alongside a reduced-calorie diet and more physical activity.
They are authorised for adults with obesity, or with overweight and weight-related health problems, rather than for cosmetic weight loss. They are not authorised for weight management outside those criteria.
What side effects are common?
The side effects people notice most often involve the digestive system: nausea, vomiting, diarrhoea, constipation, bloating, indigestion and a reduced appetite. They are more likely when treatment starts or when the dose goes up.
This is one reason the dose is started low and increased in steps, typically every four weeks, rather than begun at full strength.
Other effects can include headache, dizziness, tiredness, and redness or itching where the injection was given. Hair loss has also been reported, though less often. It is worth mentioning to the prescriber, and if shedding continues, it can be worth having hair loss assessed separately.
Milder side effects may ease as the body adjusts, but this varies. If they persist, or make it hard to eat and drink, the prescriber needs to know, because ongoing vomiting or diarrhoea can lead to dehydration. A medicine should not be changed or stopped without discussing it with the prescriber first.
What are the rarer but serious risks?
Serious side effects are uncommon, which is different from saying they do not happen. These are the ones to know about.
Inflammation of the pancreas (pancreatitis). The typical warning sign is severe stomach pain, sometimes spreading to the back, with or without vomiting. It is uncommon, but it needs urgent attention.
Gallbladder problems, including gallstones. Losing weight quickly can itself raise this risk. Warning signs include severe pain in the upper abdomen, fever, or yellowing of the skin or eyes.
Dehydration and kidney strain, usually as a consequence of prolonged vomiting or diarrhoea.
Low blood sugar, mainly in people who also take certain diabetes medicines, such as insulin or sulfonylureas.
Serious allergic reactions, which are rare but need immediate attention.
Changes in vision in people with diabetes-related eye disease. Any sudden loss or rapid worsening of vision should be assessed promptly.
Some GLP-1 medicines carry warnings relating to thyroid C-cell tumours. Tell the prescriber about any personal or family history of thyroid cancer or MEN 2 so they can assess whether treatment is appropriate. A new lump in the neck, lasting hoarseness or trouble swallowing should be reported promptly.
If any of these warning signs appear, the box near the top of this page explains when to seek urgent help.
Who should not use them, or needs extra caution?
These medicines are not suitable for everyone. They are not used during pregnancy or while breastfeeding, and Mayo Clinic advises stopping semaglutide at least two months before a planned pregnancy. Reliable contraception during treatment is advised for anyone who could become pregnant, and the WHO guideline on GLP-1 therapies excludes pregnancy from its recommendations.
Extra caution, or a different approach, may be needed if you have had pancreatitis, gallbladder disease, kidney disease or diabetes-related eye disease; if you have type 1 diabetes; or if you have severe gastroparesis, a condition in which the stomach empties very slowly. It also matters if you take other medicines, including diabetes treatments.
Tell the anaesthetist before any operation, because these medicines slow stomach emptying and raise the risk of food or fluid entering the lungs under anaesthesia or deep sedation. It is also worth telling the prescriber about your mental health history.
None of this is a checklist to apply to yourself. It is the kind of history a physician reviews before judging whether a medicine is appropriate, and it is part of why these injections are prescription-only.
Why supervision and authorised supply matter
Some of the risk around these medicines has nothing to do with the medicines themselves. In August 2025, Swissmedic, the Swiss Agency for Therapeutic Products, warned about a growing number of falsified, misleading or unauthorised products that refer to GLP-1.
Its warning describes capsules and drops sold as supplements with invented quality seals and misused regulatory logos, supposedly natural products found to contain semaglutide, and pens whose labels had been swapped so that insulin was sold as a slimming product. Healthy people injecting insulin in this way can develop life-threatening low blood sugar, and medical emergencies of this kind have been reported in Switzerland.
Swissmedic cautions that injectable products offered in cosmetic studios or beauty salons are in many cases illegal, and it advises against buying medicines from unknown sources online or on social media. The WHO makes a similar point: quality depends on regulated distribution and prescription by a qualified professional.
What happens if treatment stops?
Weight often returns after these medicines are stopped, and many people regain some of the weight they lost.
The WHO describes obesity as a chronic, relapsing disease, and its 2025 guideline on GLP-1 therapies notes that data on long-term safety, maintenance and stopping are still limited. This is information, not a reason for alarm. It is one reason these medicines are prescribed alongside changes to eating and activity, and why stopping is a decision to plan with the prescriber. The everyday foundations (eating, activity, sleep) matter with or without medication.
How is safety monitored during treatment?
In practice, safety depends as much on how a medicine is used as on the medicine itself. The dose is started low and increased in steps, which gives the body time to adjust. Regular reviews check how the medicine is tolerated, with blood and urine tests where needed and a look at any other medicines you take.
Eating remains part of treatment. Eating habits, behaviour change and physical activity remain part of treatment, and structured nutrition support can help with planning meals while appetite is reduced.
No clinician can tell you in advance exactly how your body will respond, or which side effects you will notice. What can be offered is a careful assessment beforehand, a gradual plan, and agreed points at which to review how things are going.
How is weight management care organised in Switzerland?
A family doctor is the usual first point of contact. In family-doctor, HMO and Telmed insurance models, your first contact is expected to go through the doctor or service your model specifies. Specialists in endocrinology and diabetology, and specialised obesity centres, treat more complex situations.
Basic insurance can cover weight-regulation injections, but only under conditions set by the Federal Office of Public Health (BAG). For semaglutide and tirzepatide, these include a BMI of 35 or more, or of 28 or more with conditions such as prediabetes, type 2 diabetes, high blood pressure or raised blood fats, which is higher than the threshold in the authorisation itself. Liraglutide is listed under its own limitations.
The other conditions are a documented reduced-calorie diet with accompanying nutritional counselling, documented physical activity and prior approval from the insurer. Prescription and follow-up checks must take place in person with a specialist in endocrinology and diabetology or at a qualifying obesity centre.
Treatment must show a defined response at set review points to remain covered, and reimbursement is limited to three years in total. Both listings are currently temporary, so these conditions may change. Where cover applies, your deductible and co-payment apply in the usual way; outside these conditions, treatment is generally paid privately.
Frequently asked questions
Are weight loss injections authorised in Switzerland?
Does basic insurance pay for weight loss injections?
Are injections bought online without a prescription safe?
Do the side effects go away?
Can I stop the injections if I want to?
Weight management at ahtida Health
ahtida Health is a structured digital medical clinic, and weight management is one of its areas of care. Consultations are available in German and English, and you can learn more about its approach to weight management.
If you want to take this further
There is no need to decide anything today. When you feel ready, you can explore your options for weight management and learn what an assessment may involve.
References
- Cleveland Clinic. GLP-1 Agonists. Last updated 3 July 2023.
- Cleveland Clinic. Semaglutide Injection (weight management). Date not stated on page.
- Mayo Clinic. Prescription weight-loss drugs. 21 January 2026.
- Mayo Clinic. Semaglutide (subcutaneous route): side effects and dosage. Portions last updated 1 August 2026.
- Mayo Clinic Health System. Gallstones. Date not stated on page.
- Swissmedic. Swissmedic issues warning against falsified and misleading “GLP-1” weight loss products. 26 August 2025.
- World Health Organization. WHO issues global guideline on the use of GLP-1 medicines in treating obesity. 1 December 2025.
- Federal Office of Public Health (BAG). Decision admitting semaglutide 2.4 mg for weight regulation to the list of pharmaceutical specialities (Spezialitätenliste), effective 1 March 2024.
- Federal Office of Public Health (BAG). Decision extending the reimbursement limitation of tirzepatide to weight regulation, effective 1 January 2026.
- Federal Office of Public Health (BAG). Letter to health insurers on the reimbursement of GLP-1 receptor agonists for weight regulation. 15 May 2025.
- ch.ch (Swiss federal portal). Emergencies and danger. Date not stated on page.
- ch.ch (Swiss federal portal). Taking out, changing and cancelling health insurance. Date not stated on page.
- ch.ch (Swiss federal portal). Health insurance costs and premium reductions. Date not stated on page.