Appetite suppressants: what actually works against hunger?

What suppresses appetite? The three mechanisms explained

Appetite suppressants work through three routes: they fill your stomach, they slow your digestion, or they change the hunger signal in your brain. Each mechanism has a different strength and a different level of evidence.

1. Volume in the stomach: fibres that swell

Soluble fibres absorb water and form a gel in your stomach. That gel takes up space, stretches the stomach wall and sends a mechanical signal to your brain that something has arrived. Glucomannan, psyllium and guar gum work this way.

The effect is real, but modest and short-lived. Your stomach is empty again after a few hours and the signal disappears. It also only works if you drink enough water with it. Without water the fibre doesn't swell, and in the worst case it gets stuck in your oesophagus.

2. Slower digestion: holding on to fullness for longer

Some products slow down the speed at which your stomach empties into your intestines. The longer food stays in your stomach, the longer you feel full and the less quickly you get hungry again.

Fibres do this to a small degree. Protein-rich food does it considerably better, and without a pill. Medicines from the GLP-1 group do it most strongly of all: they markedly slow gastric emptying, which is the main reason users say they are already full halfway through their plate.

3. The hunger signal in your brain

The third route is the most powerful: acting directly on the satiety centre in your brain. After a meal, your gut produces the hormone GLP-1. That hormone tells your brain that food has come in and that you can stop eating. Normally the effect lasts only a short time.

Appetite-suppressing medication mimics this hormone, but with a duration of action of days instead of minutes. The result is that the background noise of hunger largely falls silent. Your willpower doesn't get stronger; the signal gets weaker.

A second group of prescription medicines acts on other brain chemicals linked to appetite and reward. These are also only available on prescription and belong within a medical treatment.

Why "just eating less" works for some people and not for others

Your hunger system has a built-in fallback setting. When you lose weight, your body responds with more hunger hormone and less satiety hormone, and at the same time with lower energy use at rest. That is not a lack of discipline but a survival mechanism that kicks in for everyone.

The difference lies in the height of that threshold. In someone with a healthy weight, the effect is small and temporary. In people with long-standing, significant excess weight, the system is set more strongly and the effect lasts longer, sometimes for years after the weight has come off. That explains why the third and fourth diet get harder rather than easier.

An appetite suppressant that only fills your stomach does nothing about this mechanism. Something that influences the hormonal signal itself does. That is the whole difference between the two categories you'll come across in the rest of this article.

Natural appetite suppressants: what is actually proven?

For almost no over-the-counter slimming product has the effect been convincingly demonstrated. The Voedingscentrum (the Netherlands Nutrition Centre) is brief about it: the effect of no single slimming product has been demonstrated, because the underlying research is usually small, short and of moderate quality.

That is an uncomfortable message in a market that runs on hope. We think it is more important that you know this before you invest money and time again in something that didn't work last time either.

The exception: glucomannan

Glucomannan is the only product in this category with an officially approved European claim. Regulation (EU) No 432/2012 contains the claim that glucomannan, in the context of an energy-restricted diet, contributes to weight loss, under one strict condition: at least 3 grams per day, divided into three doses of 1 gram, each taken with one to two glasses of water before a meal.

Read that condition again. The effect only applies within a reduced-calorie diet, and only at that dosage and intake rhythm. So glucomannan is not an appetite suppressant that does the work for you, but support for a diet you keep up yourself. The average additional weight loss in studies is limited to a few kilos, and the effects are not found in every study.

What else you'll find on the shelves

Psyllium and guar gum. Like glucomannan, soluble fibres that bind water and fill the stomach. They demonstrably improve your bowel movements and lower your cholesterol, but for weight loss the evidence is weaker than for glucomannan. As an aid to fullness with a meal they are useful; as a slimming product they are not.

Caffeine, green tea and yerba mate. These slightly raise your metabolism and temporarily suppress your appetite. The long-term effect on your weight is negligible and you get used to them quickly. At high doses they cause palpitations, restlessness and sleep problems. Don't combine them with blood pressure medication without first talking to your pharmacist.

Saffron, fenugreek, garcinia cambogia and chromium. Popular in "best appetite suppressant" lists, but the research behind them consists mainly of small studies, often funded by the manufacturer. None of these substances has an authorised European claim for weight loss. For garcinia cambogia, reports of liver problems are also known.

Protein and fibre from ordinary food. This is the most boring and at the same time the best-supported "natural appetite suppressant" there is. A breakfast with 30 grams of protein demonstrably does more for your fullness until lunch than any capsule.

Meal replacements and shakes. These don't work as an appetite suppressant but as calorie restriction in a fixed form. As long as you keep them up, you lose weight. The problem comes the moment you stop, because your hunger system hasn't changed in the meantime.

The newest category is the so-called GLP-1 supplements: herbal preparations that claim to do the same as prescription medication. They contain no active substance that can deliver on that. By law, a supplement is also not allowed to have a medicinal effect, so the claim and the product contradict each other by definition.

What the past can teach us

For years, sibutramine was the best-known prescription appetite suppressant in the Netherlands. It worked, but it was withdrawn from the market in 2010 because of an increased risk of cardiovascular problems. The same goes for ephedra and yohimbe, which are now banned in supplements.

That history explains why the current generation of appetite-suppressing medication is so tightly regulated, and why "strong appetite suppressants" you can order online without a prescription are suspect by definition.

Which appetite suppressant actually works? Ranked by strength of evidence

Ranked by the strength of the evidence, the field looks like this, from strong to weak.

1. Prescription appetite-suppressing medication (GLP-1 group). The strongest evidence, from large randomised trials with thousands of participants. Only available through a doctor, and only worthwhile within a supervised programme.

2. Other prescription medication for obesity. Products that act on other brain chemicals or on fat absorption. Proven effective, but on average with a smaller effect than the GLP-1 group and with their own side effect profile.

3. Glucomannan. The only over-the-counter product with an authorised European claim, provided you take 3 grams per day within an energy-restricted diet. Modest effect.

4. Protein- and fibre-rich food. Not a pill, but the most reliable everyday tool against hunger that you control yourself.

5. Other herbal and caffeine preparations. Weak to no evidence. The money you spend on them mainly buys hope.

6. "Strong appetite suppressants" without a prescription from foreign websites. Not advisable. You don't know what's in them, and in the Netherlands it is not legal to sell prescription-only medicines without a prescription.

Don't read this ranking as an order in which to work through everything. It says something about strength of evidence, not about what suits you. Someone who wants to lose five kilos and can eat in a structured way gains nothing from position 1 and a lot from position 4. Someone with a BMI above 30 who has been making a serious effort for three years is wasting time on positions 3 and 5.

So the key question is not "which appetite suppressant is best", but "how serious is my problem and which tool fits it". Using a fibre capsule against a dysregulated hunger system is like putting a plaster on a fracture. Conversely, for someone who is only slightly overweight, medication is heavier than the complaint.

What you can do yourself about hunger

Four lifestyle factors demonstrably influence your hunger, and none of them costs a pill. They don't work as strongly as medication, but they always work and they are the foundation of every programme.

Eat enough protein, spread across the day. Protein is the macronutrient with the strongest satiety effect. Around 25 to 30 grams at breakfast makes the difference between grazing around eleven o'clock or not. Think of quark, eggs, chicken breast, pulses or a protein-rich version of your usual breakfast.

Sleep seven to nine hours. Lack of sleep raises your hunger hormone ghrelin and lowers your satiety hormone leptin. Two short nights in a row are enough to measurably increase your cravings for sugar and fat. This is probably the most underestimated appetite suppressant there is.

Recognise stress eating and thirst eating. A good part of what feels like hunger is tension or thirst. The simplest test is a glass of water and ten minutes of waiting. If the hunger stays, it's hunger. If it goes away, it was something else.

Build volume into your meals. Vegetables, pulses and soup provide a lot of volume for few calories. Your stomach responds to volume, not calories. A plate that looks full and fills you up does the same in practice as a fibre capsule, only without the capsule.

What these four factors can not do: reverse the hormonal hunger system that becomes dysregulated with long-standing, significant excess weight. They make the difference between hard and slightly less hard. For people who have been doing their utmost on this front for years and still get stuck, the solution lies elsewhere.

Prescription appetite suppressants: how does appetite-suppressing medication work?

Prescription appetite-suppressing medication works by mimicking the satiety hormone GLP-1, which makes your stomach empty more slowly and gives your brain the "full" signal sooner. For weight treatment, the College ter Beoordeling van Geneesmiddelen (CBG, the Dutch Medicines Evaluation Board) lists liraglutide (Saxenda), semaglutide (Wegovy) and tirzepatide (Mounjaro), among others, alongside products with a completely different mechanism of action such as orlistat and the combination of bupropion with naltrexone (Mysimba).

The medicines differ from one another. You inject liraglutide daily, semaglutide and tirzepatide weekly. Tirzepatide acts on two hormone receptors at once instead of one. Semaglutide also exists in tablet form (Rybelsus), although in the Netherlands that form is registered for diabetes and not for weight treatment. Which medicine suits you, and whether a medicine suits you at all, is a medical judgement a doctor makes. More about Saxenda vs Mysimba.

What the research shows

In the SURMOUNT-1 trial, published in the New England Journal of Medicine, 2,539 adults with obesity received weekly tirzepatide or a placebo for 72 weeks. Average weight loss reached 15.0% at the lowest dose and 20.9% at the highest, compared with 3.1% in the placebo group.

These are study averages under trial conditions, not a promise. What the figures do show: the gap between this category and everything available over the counter is large. No supplement comes close to results like these.

An important detail from the same field of research: if you stop the medication, the hunger comes back, and with the hunger often some of the kilos too. Appetite-suppressing medication is therefore not a course of a few weeks but a treatment that you build up, evaluate and at some point taper off together with your doctor.

What you can realistically expect

Weight loss with appetite-suppressing medication is gradual, not a sprint. The dose is increased in steps, usually over several months, to limit stomach and bowel complaints. The first thing people notice is not the scales but the calm: the constant negotiating with yourself about food falls away.

Study averages also say little about any one person. The same studies show a wide spread, from people who lose well over a quarter of their weight to people for whom the effect is disappointing. If a medicine doesn't work well enough for you, that is a medical signal and not a personal failure. Your doctor can then adjust the dose, consider another medicine or conclude that this route is not the one for you.

What medication doesn't do: protect your muscle mass, improve your fitness or rebuild your eating pattern for you. With significant weight loss you also lose muscle. Strength training and enough protein are therefore not a side issue in such a programme but a condition for coming out of it stronger rather than weaker.

Why your GP often doesn't prescribe it

GPs (huisartsen, the family doctors who are your first point of contact in Dutch healthcare) are cautious about weight loss medication, and there are good reasons for that. The guideline sets strict conditions, the medicines are not reimbursed in most situations, there have been periods of supply shortages in which people with diabetes were given priority, and it requires frequent monitoring that doesn't fit into every surgery hour.

That doesn't mean you have no options. It means the assessment and supervision have to come from elsewhere, from a doctor who does have the time and structure for it. Always discuss a programme outside your GP with your own GP, especially if you take other medicines.

Why the supervision makes the difference

The medication takes away the hunger. The supervision makes sure you use that space to build something that lasts. That's why medical weight loss with injections always includes a doctor who builds up your dose, monitors your symptoms and adjusts in good time.

With us, the same BIG-registered doctor (the BIG register is the Dutch register of healthcare professionals) carries out your intake and your follow-up consultations, every four weeks, one to one. No rotating team and no chatbot. If you notice side effects, you discuss them with your doctor in between appointments, and you can always pause or stop. The medication is delivered to your home by a pharmacy.

Most people notice the first effect after about four weeks. Not as a jolt, but as something that falls away: the constant calculating about food stops.

Do you recognise that your hunger is stronger than your willpower? At Qlinic, your own BIG-registered doctor personally assesses whether medical weight loss suits your situation, with follow-up consultations every four weeks. See if it's right for you →

Side effects and safe use of appetite suppressants

Every appetite suppressant that does something can also cause side effects. That applies to the fibre capsule from the chemist, and certainly to prescription medication.

Over-the-counter products. Fibre preparations mainly cause bloating, wind, stomach cramps or, conversely, constipation. Always take them with plenty of water and not just before going to sleep. Slimming products containing caffeine can cause palpitations, restlessness, headaches and raised blood pressure. If you already take medicines, check with your pharmacist: a supplement can also affect how your medication works.

Prescription medication. The most common complaints in the GLP-1 group are nausea, vomiting, diarrhoea, constipation and abdominal pain, usually in the first weeks and around a dose increase. A small proportion of users experience more serious problems, such as gallstones or inflammation of the pancreas. A full picture is given in the patient information leaflet of the specific medicine and in the overview of GLP-1 side effects.

That sounds heavier than it often turns out in practice, but it is exactly the reason a doctor increases the dose slowly and keeps monitoring you along the way. Most stomach complaints can be well limited with a slower build-up and adjustments in what and how you eat.

What helps against the nausea

Five adjustments noticeably reduce stomach complaints with appetite-suppressing medication, and they help most in the first weeks and around each dose increase.

1. Eat smaller portions and stop as soon as you're full, even if your plate isn't empty. Your stomach has less room than you're used to.
2. Limit fat and fried food. Fat slows gastric emptying even further, which is exactly what the medication already does.
3. Drink throughout the day and not in large amounts during meals.
4. Eat slowly and chew well. Eating fast is the most common cause of feeling sick afterwards.
5. Keep your fibre intake up and move every day, to prevent constipation.

If the complaints persist after a few weeks, if you can't keep enough down or if you're losing weight too fast, tell your doctor rather than pushing on. Often a longer pause on the same dose is enough. You can always pause or stop, and that is not a failure but part of good care.

When to get in touch straight away

Contact your doctor if you have persistent vomiting, severe abdominal pain radiating to your back, signs of dehydration or intense pain in the upper right of your abdomen. These are the symptoms where a quick look matters. With us, your own doctor then looks into it, precisely because the vast majority of reports turn out to be harmless and the rest need to be picked up quickly.

Buying without a prescription: don't do it

Buying prescription-only appetite suppressants without a prescription is illegal in the Netherlands, and potentially life-threatening. The CBG warns plainly that with online offers without a prescription, you don't know what you're buying. Counterfeit injection pens have been found in the European supply chain: pens with no active substance, with the wrong dose or with substances that don't belong in them at all.

There is only one legal route: a doctor assesses whether the medicine suits you, prescribes it, and a registered pharmacy supplies it. That is neither complicated nor slow. It is simply the only route in which someone with a BIG registration keeps an eye on things if something goes wrong.

Who is medical weight loss with appetite-suppressing medication suitable for?

Appetite-suppressing medication is intended for adults whose excess weight is a medical problem and for whom lifestyle change alone doesn't achieve enough. Thuisarts.nl (the Dutch GP association's patient website) describes exactly when medicines for obesity come into the picture and stresses that healthy eating and enough exercise remain the foundation. Medication is an addition, never a replacement.

That doesn't mean you may only consider it once you've "tried hard enough". If you've been making a serious effort for years, reality overtook that argument long ago.

The people we see usually recognise themselves in this picture: you've done several diets that worked at first, you started exercising, and by now you know exactly what you should be eating. And yet the weight is still there, or back.

Hunger during menopause

Women going through menopause run into this even more. Falling oestrogen levels change where your body stores fat, from hips to belly, and at the same time affect your satiety signals and your sleep. Worse sleep means more ghrelin, and more ghrelin means more appetite.

The result is a combination that many women experience as unfair, and it is: the same eating pattern that worked ten years ago now leads to weight gain. That's not a matter of trying less hard. It is a changed system that you keep pushing against with the same tools.

An appetite suppressant from the chemist doesn't change that. What does help is an approach that takes the hormonal picture seriously: strength training to preserve muscle, enough protein, attention to sleep, and with significant excess weight a medical assessment of whether appetite-suppressing medication is appropriate.

A first orientation starts with your weight and height. Calculate your BMI to see where you stand. Whether medical weight loss actually suits you depends on more than that one number: your medical history, the medication you use and what you've tried before. That judgement is made by the doctor during the intake, not by a calculator.

What a programme with us looks like

It works in three steps. First a consultation and intake in which the doctor goes through your situation and assesses whether treatment is appropriate. Then, if it is, the prescription and delivery of the medication to your home. After that, the programme itself, with a follow-up consultation every four weeks with the same doctor.

We are deliberately small-scale. So far about fifty people have been supported by us, and on Google we have a 5.0 rating from more than twenty reviews. You can start fully online, wherever you live in the Netherlands, with home delivery of the medication.

What we are not: the cheapest. We work with one fixed doctor per client, and that takes time. If you're looking on price, there are other providers. If you want someone who knows your file, we're a good fit.

And then? What happens when the programme ends

Stopping appetite-suppressing medication means your hunger comes back. That is not a side effect but the logical consequence of the fact that the medication suppressed a signal for as long as you used it. If you know that, you can prepare for it. If you don't, it comes as a shock.

That's why the question "what do we do afterwards" is part of the conversation from the start, not something for the last consultation. Some people taper off as soon as their weight is stable and their eating pattern is in place. Others continue for longer on a lower dose. Others again stop because the effect is disappointing or the side effects don't go away.

The period in which the medication dampens your hunger is the period in which you can build something that lasts: strength training, an eating pattern with enough protein, better sleep and a realistic picture of what your body needs. That is the real work. The medication only makes room for it.

Have you been stuck for years with hunger that won't go away? One personal intake with your own BIG-registered doctor gives you clarity about what is medically possible in your situation. See if it's right for you →

Frequently asked questions about appetite suppressants

Which appetite suppressant actually works?

Prescription appetite-suppressing medication from the GLP-1 group has by far the strongest evidence. In large randomised trials, this category leads to considerably greater weight loss than placebo. Of the over-the-counter products, glucomannan is the only one with an authorised European health claim, with a modest effect and only within an energy-restricted diet. For the other supplements, convincing evidence is lacking.

What is the best way to suppress appetite?

That depends on where you're starting from. If you want to support your diet, protein-rich meals and enough fibre are the most reliable and the cheapest. If losing weight doesn't work despite years of effort and you have significant excess weight, prescription appetite-suppressing medication is the only category with a large and demonstrable effect. A doctor assesses whether that suits you.

What suppresses appetite?

Three things demonstrably suppress your appetite: volume in your stomach, slower gastric emptying and satiety signals in your brain. Fibres such as glucomannan work through the first mechanism, protein-rich food through the second, and prescription medication from the GLP-1 group through all three at once. Enough sleep and limiting stress also help, because lack of sleep disrupts your hunger hormones.

What is the best natural appetite suppressant?

Glucomannan, by a distance. It is the only natural product for which the European Union has authorised a health claim for weight loss, at 3 grams per day divided into three doses with water before meals, within an energy-restricted diet. Don't expect miracles: the effect is a few extra kilos over a diet period. In practice, protein-rich food often does more for your fullness.

Can you buy strong appetite suppressants without a prescription?

No, and offers that suggest otherwise are illegal or counterfeit. In the Netherlands, prescription-only appetite suppressants may only be supplied after assessment by a doctor. Counterfeit injection pens have been in circulation with the wrong dose or no active substance. Never buy these medicines through a website that doesn't ask for a prescription, even if the packaging looks genuine.

Can you buy appetite suppressants at Holland & Barrett or Etos?

Yes, but only supplements, not medicines. What you'll find at the chemist and the health food shop are fibre preparations and herbal extracts with glucomannan, green tea or similar ingredients. For most of those products the effect has not been demonstrated. You can only get appetite-suppressing medication on prescription, through a doctor and a registered pharmacy.

What are people's experiences with appetite suppressants?

With supplements, experiences vary widely and the effect usually disappears after a few weeks. With appetite-suppressing medication, users mainly describe that the constant thinking about food falls silent and that they feel full sooner during a meal. The first weeks often come with nausea or bowel complaints. Experiences are personal and say nothing about what will happen for you.

What does a programme with appetite-suppressing medication cost?

With us you pay a one-off supervision fee of €400, plus a monthly amount that depends on the programme and ranges from €250 to €850 per month. Consultations, prescription, home delivery and the follow-up checks every four weeks are included. Different amounts apply to the three-month programmes. The current overview of medical weight loss costs is on our pricing page.

How quickly do you notice anything from an appetite suppressant?

With fibre preparations you notice something straight away during the meal, but the effect on your weight is small. With appetite-suppressing medication, most people notice after about four weeks that their hunger decreases. That's because the dose is increased step by step to limit side effects. If you notice too little effect after a few months, you discuss with your doctor whether adjusting or stopping is wiser.