Appetite Suppressants in the UK: Licensed Medicines, Supplements and What to Avoid

In the UK, the medicines licensed for weight management that work by reducing appetite are prescription medicines: GLP-1 medicines such as Wegovy, Mounjaro and Saxenda, the Foundayo tablet, and Mysimba. Pills, teas and supplements sold as appetite suppressants are not licensed medicines. This guide explains the difference, using the UK product information, the MHRA and NICE.

What Counts as an Appetite Suppressant?

Licensed prescription medicines, food supplements, and unlicensed or illegal products.

An appetite suppressant is anything claimed to make you feel less hungry or fuller sooner. In the UK there are three very different groups:

• Licensed medicines that reduce appetite as part of weight management. They have been assessed by the Medicines and Healthcare products Regulatory Agency (MHRA) and are prescribed after a check that they are suitable.

• Food supplements, which can only make health claims authorised on the Great Britain register, and cannot claim to treat obesity.

• Unlicensed or illegal products sold online, which may not contain what they say.

Licensed Medicines That Reduce Appetite

Wegovy, Mounjaro, Saxenda, Foundayo and Mysimba, licensed for weight management.

These medicines are licensed for weight management alongside a reduced-calorie diet and more physical activity, in adults with a body mass index (BMI) of 30 kg/m² or more, or 27 kg/m² or more with a weight-related condition:

• Wegovy (semaglutide), a weekly injection or daily tablet. Its SmPC says it acts on brain areas that regulate appetite. See what is Wegovy.

• Mounjaro (tirzepatide), a weekly injection acting on GIP and GLP-1 receptors. Its SmPC says it increases fullness and decreases hunger and cravings. See how Mounjaro works.

• Saxenda (liraglutide), a daily injection. Its SmPC describes increased fullness and decreased hunger signals in animal studies.

• Foundayo (orforglipron), a daily tablet licensed for weight management and type 2 diabetes.

• Mysimba (naltrexone/bupropion), a twice-daily tablet acting on the brain's hunger and reward areas. NICE does not recommend it on the NHS. See Mysimba.

The MHRA says these GLP-1 medicines should only be taken as prescribed by a healthcare professional. Ozempic and Rybelsus contain semaglutide too, but are licensed for type 2 diabetes, not weight management.

What About Orlistat?

A licensed weight-loss medicine, but it blocks fat absorption rather than reducing appetite.

Orlistat (Xenical on prescription, alli from pharmacies) is a licensed weight-loss medicine, but it is not an appetite suppressant. It works in the gut by blocking some of the fat you eat from being absorbed. See orlistat.

Appetite Suppressant Supplements, Teas and Pills

Not medicines; they can only make authorised health claims, and regulators doubt unlicensed slimming products work.

Supplements sold for appetite control are foods, not medicines. In Great Britain, a food supplement can only make a health claim that is authorised on the GB nutrition and health claims register. For example, glucomannan, a type of fibre, has an authorised claim that "in the context of an energy restricted diet" it "contributes to weight loss".

The advertising regulators' guidance says that neither CAP nor the ASA has seen convincing evidence that unlicensed slimming pills, herbal remedies and patches can result in weight loss. The ASA has also ruled against supplements claiming to boost GLP-1 naturally or to work like weight-loss injections. See GLP-1 patches, drops and oral solutions.

Why to Avoid Diet Pills Sold Online

Illegal products may be fake or contaminated; the MHRA says walk away from GLP-1s offered without a prescription.

The MHRA warns that weight-loss products sold illegally "may be fake, contaminated, incorrectly dosed, or contain powerful ingredients not listed on the packaging". Its advice:

• If you are offered a GLP-1 medicine without the need for a prescription, walk away.

• Avoid weight-loss products promoted on social media with "quick fixes", "miracle results" or unusually low prices.

• Check that a pharmacy is registered with the General Pharmaceutical Council (GPhC) in Great Britain, or the Pharmaceutical Society of Northern Ireland (PSNI).

• Retatrutide has not been authorised for use in the UK, so anyone selling it is doing so illegally.

Report suspicious products and any side effects to the MHRA Yellow Card scheme.

Who Can Get a Prescription Appetite Suppressant?

Adults with a BMI of 30+, or 27+ with a weight-related condition, after a prescriber's check.

The licensed medicines above are for adults with a BMI of 30 or more, or 27 or more with a weight-related condition such as high blood pressure, prediabetes or type 2 diabetes. The MHRA notes that GLP-1 medicines authorised in the UK have only been shown to be safe and effective for people with a BMI of 27 or more.

A prescriber checks your health, other medicines and whether a medicine is suitable. On the NHS, NICE guidance sets narrower criteria, and access depends on local services.

Side Effects of Prescription Appetite Suppressants

Mostly stomach-related for GLP-1 medicines; Mysimba has warnings on mood and seizures.

Side effects depend on the medicine. For the GLP-1 medicines the most common are stomach-related, such as nausea, diarrhoea, vomiting and constipation, mostly while the dose is increasing; Mysimba has its own warnings, including on mood and seizures. Seek immediate medical attention for persistent, severe stomach pain on a GLP-1 medicine, which can be a sign of pancreatitis.

The MHRA advises not to take GLP-1 medicines if you are pregnant, trying to get pregnant or breastfeeding. See Wegovy side effects and Mounjaro side effects.

Frequently Asked Questions