All about GLP-1

What is GLP-1?

GLP-1 (glucagon-like peptide-1) is a hormone that your small intestine produces as soon as food passes through. It signals your pancreas to release insulin, suppresses the hormone glucagon, slows down the emptying of your stomach and tells your brain that you are full. GLP-1 medicines mimic this hormone.

GLP-1 belongs to the incretin hormones: substances your gut releases after a meal to keep your blood sugar in balance. So your body makes it itself, every time you eat. Natural GLP-1 is broken down again within a few minutes, which means its effect is short and tied to each meal.

That short action explains why the hormone itself is not a medicine. The medicines based on it work for hours up to a week. They form the basis of virtually all modern weight loss medication and of a large share of diabetes medicines.

What does GLP-1 do in your body?

GLP-1 acts in four places at once: in your brain, in your stomach, in your pancreas and, through that, on your blood sugar. Together these four effects mean that you eat less and that your blood sugar rises less sharply after a meal.

• Appetite: GLP-1 activates receptors in the part of your brain that regulates hunger. The hunger signal becomes weaker. This is why GLP-1 medication is experienced as an appetite suppressant.
• Satiety: you feel full sooner and for longer. Smaller portions therefore feel like enough.
• Gastric emptying: your stomach passes food on to your intestines more slowly. A meal stays with you longer and you get hungry again less quickly. This effect also causes the nausea that many users notice at the start.
• Blood sugar: after eating, your pancreas releases more insulin and less glucagon. Your blood sugar peaks less. In type 2 diabetes this natural effect is weakened, which explains why these medicines were first developed as diabetes medicines.

So the hormone is not a "fat burner". It changes how much you eat and how your body handles sugar. Weight loss is the result of that lower intake, not of a direct effect on fat.

What are GLP-1 agonists and how do they differ from the hormone?

GLP-1 agonists are medicines that activate the same receptor as the natural hormone, but keep working for days up to a week. You will also see the names GLP-1 receptor agonist and GLP-1 analogue; these are three terms for the same group of medicines.

The difference lies in the structure of the molecule. Manufacturers modify the hormone so that the body does not break it down within minutes. Semaglutide stays active for about a week, liraglutide for about a day. As a result, the "you are full" signal is no longer a short peak after each meal, but a constant level. According to the group text of the Farmacotherapeutisch Kompas (the Dutch reference work on medicines) of Zorginstituut Nederland (the Dutch National Health Care Institute), this leads to more insulin, less glucagon, slower gastric emptying and a stronger feeling of satiety.

A newer variant acts on two gut hormones at once. Tirzepatide, the active ingredient of Mounjaro, activates the receptor of GIP as well as the GLP-1 receptor. Officially it is therefore a GLP-1/GIP receptor agonist, but in practice it is counted as GLP-1 medication.

Because these substances are proteins that your stomach breaks down, they are usually injected. There are also tablets, with an added ingredient that allows absorption through the stomach. All GLP-1 agonists are prescription medicines: a doctor first assesses whether they are right for you.

Which GLP-1 medicines are there?

In the Netherlands, seven brands are relevant, based on four active ingredients, for weight management or type 2 diabetes. The registration states what the manufacturer has had the medicine approved for; the table shows the situation as of September 2026.

Three points in the table need explaining. First, Ozempic, Wegovy and Rybelsus contain the same substance, but only Wegovy is registered for weight management. Second, Mounjaro is the only medicine that acts on two hormones; the European Medicines Agency (EMA) has authorised it since 15 September 2022, for type 2 diabetes and later also for weight management. Third, since the patent on liraglutide expired, a range of generic brands has become available alongside Saxenda.

The question about "GLP-1 pills" deserves its own answer. There are two registered tablets: Rybelsus, registered for type 2 diabetes (read more about Ozempic pills), and the Wegovy tablet, which was registered in the EU for weight management in 2026 but in September 2026 was not yet routinely stocked in Dutch pharmacies (the current situation is in our article on Wegovy tablets). Medicines still in development, such as orforglipron, are discussed in the article on the new weight loss pill. Capsules or drops from a webshop do not belong to this group; more on that further down.

Is GLP-1 the same as Ozempic?

No. GLP-1 is the hormone, semaglutide is the active ingredient that mimics that hormone and Ozempic is the brand name under which Novo Nordisk sells semaglutide as a diabetes medicine. So Ozempic is one of the GLP-1 medicines, not the same thing as GLP-1.

That distinction in three layers (hormone, substance, brand) helps with every comparison. Wegovy contains the same substance as Ozempic at a different dose and with a different registration; you can read about the difference in Wegovy vs Ozempic. Mounjaro contains a different substance, tirzepatide, which acts on two hormones; the comparison is in Mounjaro vs Ozempic.

"Buying GLP-1" therefore does not exist as a product. If you want GLP-1 medication, you get a prescription for one of the registered medicines through a doctor.

Who is GLP-1 medication for?

The registered threshold for weight management is a BMI of 30 or higher, or a BMI from 27 in combination with a weight-related condition such as high blood pressure, type 2 diabetes, sleep apnoea or raised cholesterol. That threshold applies to Wegovy, Mounjaro and Saxenda. You can work out your BMI with our BMI calculator.

Your BMI is a starting point, not an outcome. The doctor assesses whether medical weight loss is right for you, based on your health, the medicines you use and your previous attempts to lose weight. GLP-1 medication is not suitable during pregnancy, if you are trying to conceive or while breastfeeding, after previous pancreatitis (inflammation of the pancreas), with severe kidney or liver problems or with an eating disorder. At Qlinic, a minimum age of 18 also applies.

For type 2 diabetes the route is different: there, the GP or internist prescribes GLP-1 medication as part of the diabetes treatment, in line with the guideline.

Want to know whether medical weight loss suits your situation? The eligibility check takes you through the most important medical points in a few minutes and the doctor assesses the outcome. eligibility check →

What can you expect from GLP-1 medication?

Research shows that GLP-1 medication, combined with support with diet and exercise, leads to considerable weight loss. In the STEP 1 trial (New England Journal of Medicine, 2021), 1,961 adults with overweight or obesity lost an average of 14.9% of their body weight in 68 weeks with 2.4 mg of semaglutide per week, compared with 2.4% on placebo. In the SURMOUNT-1 trial (NEJM, 2022), 2,539 participants lost an average of 15% to 20.9% in 72 weeks with tirzepatide, depending on the dose, compared with 3.1% on placebo.

Those figures are averages from trials, not a promise. How much weight you lose varies from person to person and depends on the dose, your starting weight, your diet and exercise and how your body responds to the medicine. Some users barely respond. What users report in practice is covered in GLP-1 reviews.

The course is similar for all medicines. You usually notice the appetite suppression in the first weeks. Your weight then drops gradually, because the dose is built up in steps of at least 4 weeks. How that goes for each medicine is covered in how fast Ozempic works and how fast Mounjaro works. After stopping, many people regain weight; that is why tapering off with a plan is important, as described in the Ozempic tapering schedule.

GLP-1 side effects in brief

The most common side effects of GLP-1 medication are nausea, diarrhoea, constipation, vomiting and abdominal pain. According to apotheek.nl (the Dutch pharmacists' patient information website), these complaints occur in 10% to 30% of users, mainly in the first weeks and after a dose increase, and usually decrease within 4 weeks. That is why all medicines start with a low dose that goes up step by step.

Other side effects that occur regularly are fatigue, headache, a bloated feeling, heartburn and reactions at the injection site. Rare but serious are inflammation of the pancreas and gallstones. Low blood sugar occurs almost exclusively in combination with insulin or certain diabetes tablets. Muscle loss and hair loss are not direct side effects of the medicine, but consequences of losing weight quickly with too little protein.

Is GLP-1 dangerous? With a registered medicine, the correct dose and supervision by a doctor, the side effects are usually mild and temporary. Serious complaints, such as severe persistent abdominal pain, are a reason to contact your doctor immediately. The full overview, per substance and with what you can do about it yourself, is in GLP-1 side effects; the points specific to tirzepatide are in Mounjaro side effects.

Costs and reimbursement in brief

If you use GLP-1 medication to lose weight, in 2026 you usually pay for it yourself. For obesity, basic health insurance (basisverzekering) only covers liraglutide (Saxenda) and Mysimba, under strict conditions: at least one year of a recognised combined lifestyle intervention (GLI, a Dutch lifestyle programme), a BMI from 35 with a condition caused by overweight or from 40, and no type 2 diabetes. For type 2 diabetes, Ozempic, Rybelsus, Mounjaro, Victoza and Trulicity are covered under conditions.

An assessment is under way for Wegovy and Mounjaro for obesity. Zorginstituut Nederland is assessing both medicines in a phased approach, first for people with a BMI from 30 with a weight-related condition or a BMI from 35, after a lifestyle programme. Until that decision has been made, there is no reimbursement for weight loss. The current conditions per medicine are in weight loss medication covered by insurance.

At Qlinic you pay for one programme, medical weight loss with injections, with a monthly price that depends on the medication: €250 with semaglutide (Ozempic), €350 with tirzepatide (Mounjaro) or €850 with liraglutide (Saxenda), plus a one-off €400 supervision fee. A full explanation of all GLP-1 costs, with pharmacy prices per medicine, is in our cost article; the current rates are on the page medical weight loss prices.

Through your GP or through a clinic?

In the Netherlands you can get GLP-1 medication in two legal ways: through your GP (huisarts) or through a clinic with a BIG-registered doctor (the BIG register is the Dutch register of healthcare professionals). In both cases a doctor assesses whether the medicine is right for you, writes a prescription and a registered Dutch pharmacy supplies the medicine.

Your GP is allowed to prescribe GLP-1 medication, but is often cautious for overweight without diabetes. The Dutch GP guideline focuses on a lifestyle programme first, and the medication is not covered for weight loss. What you can expect from your GP is covered in weight loss medication from your GP. An online clinic follows the same legal route, with a consultation beforehand, a prescription and delivery through the pharmacy; how that works per medicine is in buying Ozempic and buying Mounjaro.

Offers without a prescription are illegal and risky. That applies to "GLP-1 ampoules", peptide webshops, foreign websites, Marktplaats (the Dutch classifieds site) and social media. Nobody checks the contents, the dose or the sterility there, and counterfeits do occur. You can recognise a registered GLP-1 medicine by the manufacturer's packaging, the patient information leaflet and the label of a Dutch pharmacy.

GLP-1 and lifestyle

GLP-1 medication works alongside diet and exercise, not instead of them. In all major trials, participants received the medicine in combination with support with eating and exercise; the results therefore apply to that combination. Because you eat less, the quality of what you do eat counts for more.

Two points deserve the most attention in practice. Enough protein and strength training limit the loss of muscle mass, which otherwise increases when you lose weight quickly. Small, fibre-rich meals and eating slowly reduce nausea and the full feeling. What is possible in terms of exercise during use is covered in Ozempic and exercise; all treatment options side by side are in obesity treatment.

Supplements with "GLP-1" in their name, such as capsules, drops or "GLP-1 boosters", contain no GLP-1 and no GLP-1 agonist. They are food supplements, not medicines, and there is no evidence that they noticeably raise the hormone. What they contain and what the research says is covered in our article on the GLP-1 supplement.

How medical weight loss with GLP-1 medication works at Qlinic

At Qlinic, medical weight loss with GLP-1 medication takes place in one programme, medical weight loss with injections, supervised by your own BIG-registered doctor. The programme starts with the eligibility check and a consultation, in which the doctor goes through your health, the medicines you use and your goal, and assesses whether medical weight loss is right for you.

If it is right for you, the doctor chooses the medicine and the dose together with you. The prescription goes to a registered Dutch pharmacy, which delivers the medication discreetly to your home. After that you see or speak to the same doctor every 4 weeks: for the dose build-up, for questions about side effects and to adjust the course where needed. You can always pause or stop, in consultation with your doctor. Who the doctors are and how they work is on the page about Qlinic.

Ready to find out what is possible in your situation? Your own doctor assesses your health, chooses the medicine with you and supports you every 4 weeks. medical weight loss with injections →

Frequently asked questions about GLP-1

Is GLP-1 dangerous for humans?

No, your body makes the hormone itself every day. GLP-1 medication is a registered medicine with known side effects, mainly gastrointestinal complaints in the first weeks. Serious side effects such as pancreatitis are rare. The medication is not suitable during pregnancy, after previous pancreatitis or with severe kidney or liver problems.

Can I lose weight with GLP-1?

Yes, with prescription GLP-1 medication, combined with changes to your diet and exercise. The medicine suppresses your appetite and slows your gastric emptying, so you eat less. The hormone alone or a supplement will not achieve that; the doctor assesses whether medical weight loss is right for you.

How much weight do you lose with GLP-1?

In the STEP 1 trial, participants lost an average of 14.9% of their weight in 68 weeks with semaglutide; in SURMOUNT-1 it was 15% to 20.9% with tirzepatide in 72 weeks. These are averages from research. How much weight you lose varies from person to person and is never a guarantee.

Which medication counts as GLP-1?

GLP-1 medication includes semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Saxenda, Victoza and generic brands), dulaglutide (Trulicity) and tirzepatide (Mounjaro), which acts on the hormone GIP as well as GLP-1. Only Wegovy, Mounjaro and Saxenda are registered for weight management.

Can I get GLP-1 medication through my GP?

Yes, a GP is allowed to prescribe GLP-1 medication. For type 2 diabetes this happens regularly. For overweight without diabetes, GPs are cautious and usually refer you to a lifestyle programme first. A clinic with a BIG-registered doctor follows the same route: consultation, prescription and delivery through a registered pharmacy.

What are the conditions for getting GLP-1 agonists reimbursed?

For weight loss, in 2026 only liraglutide (Saxenda) is covered, after at least one year of a recognised lifestyle programme and with a BMI from 35 with a weight-related condition or from 40, without type 2 diabetes. Different conditions apply for type 2 diabetes. Wegovy and Mounjaro for obesity are still being assessed by the Zorginstituut.

Where is GLP-1 found naturally?

GLP-1 is not found in food; your gut makes it itself in response to a meal. Protein, fibre and healthy fats stimulate that release slightly more than fast-acting sugars. The effect of food is much smaller than that of medication and is not a replacement for it.

Are there GLP-1 pills?

Yes, two registered tablets: Rybelsus (semaglutide, for type 2 diabetes) and the Wegovy tablet (semaglutide, for weight management, registered in the EU in 2026). Both are available on prescription only. Capsules and drops sold as a "GLP-1 pill" are supplements without an active ingredient from this group.