Medically reviewed by Dr. Meinolf Dorka, Medical Director, last reviewed September 2026
If you have been comparing weight loss injections, you have probably met strong opinions: rankings, forum threads, a friend’s experience. Wanting someone to name the right one is understandable. The honest answer is more useful, even if it is less tidy.
In short
No single injection suits everyone. Three substances are authorised in Switzerland for weight regulation: semaglutide, tirzepatide and liraglutide. They differ in how they act, how often they are injected, the evidence behind them and their side-effect profiles.
Which one is appropriate depends on your health history, other conditions and medicines, how you tolerate treatment and whether insurance criteria apply. That judgement belongs to a physician, made with you rather than for you.
The options at a glance
Semaglutide acts like the gut hormone GLP-1 and is injected once a week. Its most common side effects are nausea, diarrhoea, vomiting, constipation and stomach pain.
Tirzepatide acts on two gut hormone receptors, GIP and GLP-1, and is also injected once a week. Its most common side effects are nausea, diarrhoea, constipation and vomiting.
Liraglutide acts like GLP-1 and is injected once a day. An upset stomach and vomiting are among its most common side effects.
All three are prescription-only. They share the same rarer but serious risks, including pancreatitis and gallbladder problems, and none is used during pregnancy.
How they work
In plain terms, all three copy the action of hormones your gut releases after a meal. These hormones help signal fullness, slow how quickly food leaves the stomach and help regulate blood sugar. One effect is a reduced appetite.
Semaglutide and liraglutide act on one receptor, the GLP-1 receptor. Tirzepatide acts on two: the GLP-1 receptor and the receptor for a second hormone, GIP. This dual action is the main pharmacological difference between tirzepatide and the other two.
The practical differences are the dosing schedule and how the dose is built up. Semaglutide and tirzepatide are injected once a week, liraglutide once a day. With each, treatment starts at a low dose that is increased in steps, which helps the body adjust to digestive side effects.
What the evidence shows
Each substance has been studied in large randomised trials in adults with obesity, or with overweight and a weight-related condition, alongside advice on diet and activity. Mayo Clinic notes that prescription weight-loss medicines used for more than 12 weeks lead to greater weight loss than placebo, and that medicine combined with lifestyle change leads to more weight loss than lifestyle change alone.
Trials comparing the substances directly have also been published. They are one input a physician weighs, together with your health history, your other medicines and how you tolerate treatment.
Averages describe groups, not individuals. Participants received structured support with diet and activity, and results varied within each group. The WHO made its 2025 recommendation on these therapies conditional partly because data on long-term effectiveness and safety are still limited.
A difference between averages is one factor in a decision, not the decision itself.
How side effects compare
The side-effect profiles are broadly similar, because all three act on the same pathway. The most common effects are digestive: nausea, diarrhoea, vomiting and constipation, which tend to be more frequent while the dose is being increased.
The serious but uncommon risks, such as pancreatitis, gallbladder problems and kidney strain from dehydration, apply across the group. Knowing how a medicine performs on average does not tell you how you will tolerate it. That is learned during treatment, which is why the dose is increased gradually and reviewed.
What differs more than the profile itself is how each person experiences it. Timing, severity and how long effects last vary, and so does how much they interfere with everyday life. Effects that are manageable for one person can be the reason another stops treatment.
Practical steps help: smaller meals, eating more slowly, and telling the prescriber before side effects become difficult rather than after. If side effects are difficult, the prescriber may decide to delay a dose increase.
Other factors that shape the choice
Type 2 diabetes. Each of these substances is also used, in different doses or forms, in diabetes care. Existing diabetes medicines such as insulin or sulfonylureas may need adjusting, because the combination can cause low blood sugar.
Heart and blood vessel disease. Semaglutide is also used to lower the risk of heart attack and stroke in people with excess weight and established heart or blood vessel disease.
Daily or weekly dosing. Some people prefer a weekly injection; others prefer a daily routine. This is a legitimate part of the choice.
Health history. Previous pancreatitis, gallbladder or kidney disease, pregnancy plans, other medicines and any personal or family history of thyroid cancer or MEN 2 may all affect suitability.
Insurance criteria. Whether basic insurance can cover a particular medicine depends on conditions described further down this page.
What starting treatment involves
Whichever substance is chosen, treatment starts at a low dose and is increased gradually according to the dosing schedule for that medicine, until an effective dose is reached that you can tolerate. This helps the body adjust and allows side effects to be reviewed before the next increase.
Alongside the medicine, eating and activity remain part of the plan rather than an optional extra. In Switzerland, a documented reduced-calorie diet with nutritional counselling and documented physical activity are also among the conditions for insurance cover. Reviews look at how you are tolerating the medicine, how your weight and any related conditions are responding, and whether other medicines need adjusting.
Treatment is reviewed rather than simply continued. If a medicine is not tolerated, or the response is not what was hoped for, the dose, the substance or the whole approach can be reconsidered.
Are there alternatives to injections?
Yes. Injections are one option within weight management, not the starting point for everyone. Eating, physical activity, sleep and support with habits remain the foundation, with or without medication, and nutrition guidance can help turn that foundation into everyday meals.
An oral medicine, orlistat, reduces the amount of fat the body absorbs from food; its common side effects include passing gas and loose stools. Newer oral medicines have also become available in some countries, including Wegovy tablets (semaglutide) and Lilly’s Foundayo (orforglipron), although neither is currently available in Switzerland. Bariatric surgery may be considered for people with class III obesity.
What happens if you stop
Weight often returns after these medicines are stopped, and many people regain some of the weight they lost. That is not a reason to avoid treatment, but it is a reason to plan what comes next with the prescriber.
In Switzerland, reimbursement is time-limited and depends on treatment showing a defined response at review points. Whenever treatment ends, the transition should be planned with the prescriber, alongside continued support for eating and activity.
Why the choice is made with a physician
No clinician can responsibly predict, before treatment starts, how a particular medicine will work for you or how you will tolerate it. What a clinician can offer is an assessment of your health history, a clear explanation of which options are appropriate and which are not, and review points once treatment begins.
The decision about whether to start, and with what, remains yours.
Approval and insurance in Switzerland
Swissmedic authorised semaglutide for weight regulation in February 2022 and tirzepatide in July 2024. Liraglutide is also authorised for this use.
Basic insurance can cover these medicines for weight regulation, but only under limitations 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. These thresholds are higher than those in semaglutide’s authorisation, which covers adults with a BMI of 30 or more, or of 27 or more with a weight-related condition.
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 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. Liraglutide is also listed, under its own limitations. The semaglutide and tirzepatide listings are currently temporary, so these conditions may change, and treatment outside them is generally paid privately.
Common questions
So which is the best medication for weight loss?
Is tirzepatide a GLP-1 medicine?
Which injection has the fewest side effects?
Can I switch from one injection to another?
Can I buy these injections without a prescription?
Does basic insurance cover all three?
How long would I stay on treatment?
Are the injections meant to be used on their own?
About ahtida Health
Weight management is one of the areas of care at ahtida Health, a structured digital medical clinic. Consultations are held in German or English, and there is a fuller description of the weight management service.
Where to go from here
You do not need to arrive with a preferred option or even a clear question. If you would like to understand what may suit your situation, you can look into weight management options whenever you are ready.
References
- Cleveland Clinic. GLP-1 Agonists. Last updated 3 July 2023.
- Cleveland Clinic. Semaglutide Injection (weight management). Date not stated on page.
- Cleveland Clinic. Obesity. Last updated 10 September 2024.
- Mayo Clinic. Prescription weight-loss drugs. 21 January 2026.
- Mayo Clinic. Semaglutide (subcutaneous route): side effects and dosage. Portions last updated 1 August 2026.
- Swissmedic. Swissmedic issues warning against falsified and misleading “GLP-1” weight loss products. 26 August 2025.
- World Health Organization. WHO issues global guidelines 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.