What are appetite suppressants and do they really work?

Appetite suppressants are often mentioned alongside weight loss tablets and supplements, but appetite is more complex than simply ‘switching off’ hunger. If you’ve ever wondered whether these products actually work or if they’re something you should try – you’re not alone. To get a clearer picture, we asked Registered Nutritionist Laura Jennings what the evidence really says and what to consider before trying anything that claims to curb cravings. 

“It’s actually a broad, non-medical term,” explains Laura. “Generally, it describes anything that may help reduce feelings of hunger or help you feel fuller for longer.”¹ This could include prescription medicines, over-the-counter supplements or simply certain foods and nutrients that naturally support fullness.^{1,4, 8, 12-13,18} It’s also worth remembering that appetite isn’t something the body gets wrong.

Your appetite is guided by a constant conversation between your brain, gut and hormones.² “Hormones like ghrelin tell you when you’re hungry, while leptin helps signal fullness,” explains Laura. “Your gut also releases hormones after meals that tell the brain you’ve eaten enough.”² Blood sugar levels, digestion and even how stretched your stomach feels after eating all play a role. That’s why what you eat – and how you eat – can make such a difference to how full you feel after a meal.²

Yes – and this is where some of the strongest evidence sits. “Meals that are rich in protein and fibre tend to be more satisfying, reduce the likelihood of overeating and snacking on unhealthy food between meals,” says Laura.^4,8 Larger portions of high-fibre foods, like fruits, vegetables and legumes, also often have a lower energy density. This means they can help you feel fuller on fewer calories and support natural appetite regulation.⁸ “In most cases, everyday eating habits have a greater influence on appetite than any single supplement.”

Laura recommends:^4,8-10

By contrast, highly processed foods that are lower in fibre and protein may not feel as filling, which can make it easier to feel hungry again soon after eating.¹¹

You might see ingredients like glucomannan (a soluble fibre), green tea extract or caffeine marketed as appetite suppressants or weight loss aids.^12-14 “Some research suggests these ingredients may influence fullness or energy intake slightly,” says Laura. “However, the effects are usually modest and can vary widely between people.” Studies also tend to be small or short-term, and results aren’t always consistent.^12-14 That doesn’t mean supplements are unsafe – it simply means that claims about appetite suppression should be approached with some caution.

Yes, they’re quite different. “Prescription medicines are used under medical supervision and closely monitored by healthcare professionals,” explains Laura. “They’re typically recommended for specific health needs and are backed by more robust research than most over-the-counter supplements. If someone is considering prescription options, it’s always best to have that conversation with their healthcare practitioner first,” she adds.

Not necessarily. Some supplements or ingredients may not be suitable if you:

High-fibre ingredients can sometimes cause digestive discomfort like bloating or cramps, while stimulant-based products containing caffeine may lead to increased anxiety, jitteriness or disrupted sleep.^15-17 Prescription medicines can have additional effects and should always be used under medical supervision. “Just because something is labelled ‘natural’ doesn’t always mean it’s right for everyone,” says Laura.

The short answer is: it’s rarely that simple. There isn’t one ingredient that reliably ‘switches off’ hunger for everyone, and even prescription medications work within a complex mix of biology and behaviour. For many people, everyday habits like balanced meals, regular eating, good sleep and managing stress tend to have a bigger impact than any single supplement.^2,4-7

So, what’s the takeaway when it comes to appetite suppressants? They can mean lots of different things, from prescription medicines to simple food choices that help you feel fuller. While some products may play a small role, the effects tend to be modest and the evidence is mixed.^12-14 Building meals around protein and fibre is often more effective than chasing quick fixes.^4,8 “If something promises dramatic appetite suppression, it’s worth being sceptical,” says Laura. “Sustainable habits usually make the biggest difference.” Want to learn more? Take a look at our guide to gut health and weight loss, or explore the benefits of habit stacking.

Disclaimer – This article provides informational advice and is not a substitute for medical care. Working with experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.