Every Weight Loss Medication Available in the UK

Several weight loss medicines are licensed in the UK. At the time of writing, they are orlistat, liraglutide (Saxenda and other products), semaglutide injections (Wegovy), tirzepatide (Mounjaro), and two GLP-1 tablets approved by the MHRA in 2026: oral semaglutide (Wegovy tablets) and orforglipron (Foundayo). Naltrexone-bupropion (Mysimba) is licensed but not recommended by NICE, and setmelanotide is used only for rare genetic conditions. All except low-strength orlistat need a prescription, and each is used alongside diet and activity. This guide explains how they differ, so you can have an informed conversation with a prescriber.

The quick overview

Licences and NICE recommendations change. For the latest position, check the SmPC on medicines.org.uk, the MHRA and the NICE website.

Orlistat

How it works

Orlistat works in the gut rather than the brain. It blocks lipase, an enzyme that breaks down dietary fat, so around a third of the fat in a meal passes through the body undigested rather than being absorbed. It does not reduce appetite.

Strengths

• Xenical (120mg) is prescription-only.
• alli (60mg) is a pharmacy medicine, which means it can be supplied by a pharmacist without a prescription to adults with a BMI of 28 or above, after a consultation.

Evidence and expectations

Orlistat has been used for decades. In trials, it produces modest extra weight loss compared with diet alone, considerably less on average than modern GLP-1 medicines. It has the advantage of a long safety record and works without affecting appetite.

Side effects

Side effects are linked to undigested fat and are more likely with high-fat meals. They include oily stools, urgency, wind with oily discharge and, occasionally, faecal incontinence. A low-fat diet reduces these. Orlistat can reduce absorption of fat-soluble vitamins (A, D, E and K), so a multivitamin taken at a different time of day is often advised. It can also interact with some medicines, including ciclosporin, levothyroxine, some anti-epilepsy drugs and the contraceptive pill if it causes severe diarrhoea.

Our comparison of orlistat and GLP-1 medicines goes into more detail.

Liraglutide (Saxenda and other products)

How it works

Liraglutide was the first GLP-1 receptor agonist licensed for weight management in the UK, marketed as Saxenda. It is the same active ingredient as Victoza, which is licensed for type 2 diabetes, but at a higher dose. Generic versions of liraglutide have become available in the UK. It reduces appetite and increases fullness.

How it is taken

Liraglutide is injected once a day, starting at 0.6mg and increasing weekly to a maintenance dose of 3mg, following the schedule in the SmPC.

Evidence and NICE

In trials, liraglutide 3mg produced greater average weight loss than placebo, but less than the newer weekly medicines. NICE TA664 (2020) recommends it only in specific circumstances: within specialist weight management services, for adults with a BMI of at least 35 who also have non-diabetic hyperglycaemia and high cardiovascular risk, with lower thresholds for some ethnic groups.

Practical points

Daily injections suit some people but not others. Side effects are similar to other GLP-1 medicines. Our guide to Saxenda vs newer GLP-1s compares it with Wegovy and Mounjaro.

Semaglutide injections (Wegovy)

How it works

Wegovy is a once-weekly semaglutide injection. Semaglutide mimics GLP-1, reducing appetite and slowing stomach emptying. Our guide to how Wegovy works explains the science.

How it is taken

Treatment starts at 0.25mg weekly and increases every four weeks through 0.5mg, 1mg and 1.7mg to a standard maintenance dose of 2.4mg. In January 2026, the MHRA approved a higher maximum dose of up to 7.2mg weekly for adults with obesity (BMI 30 or above) only, based on the STEP UP trial. It does not apply to people using Wegovy with a BMI below 30 or for cardiovascular risk reduction. NICE had not appraised the higher dose at the time of writing. Our guide to Wegovy doses explains the schedule.

Evidence

In STEP 1, semaglutide 2.4mg produced average weight loss of around 15% over 68 weeks, compared with around 2% on placebo. The SELECT trial showed a reduction in major cardiovascular events in people with obesity and established cardiovascular disease, without diabetes. See our guide to Wegovy results.

NICE and NHS

NICE TA875 (2023) recommends Wegovy within specialist weight management services, for a maximum of two years, for adults meeting BMI and comorbidity criteria. Access depends on local services. See our guide to Wegovy on the NHS.

Tirzepatide (Mounjaro)

How it works

Mounjaro acts on two hormone receptors, GIP and GLP-1, which is why it is called a dual agonist. It reduces appetite and affects how the body handles glucose and fat. See how Mounjaro works.

How it is taken

Mounjaro is a once-weekly injection using a KwikPen. It starts at 2.5mg and can increase in 2.5mg steps every four weeks to a maximum of 15mg. Our guide to Mounjaro doses explains the steps.

Evidence

In SURMOUNT-1, tirzepatide at the highest dose produced average weight loss of around 20% over 72 weeks. In SURMOUNT-5, a head-to-head trial, tirzepatide produced greater average weight loss than semaglutide 2.4mg. See our guide to SURMOUNT-5.

NICE and NHS

NICE TA1026 (December 2024) recommends tirzepatide for managing overweight and obesity, with a phased rollout in NHS primary care beginning in June 2025 for people with the highest clinical need. Wraparound support on diet and activity is part of the recommendation. See our guide to Mounjaro on the NHS.

Important: tirzepatide may reduce the effectiveness of oral contraceptives. The MHRA advises a non-oral or additional barrier method for four weeks after starting and after each dose increase. See our guide to GLP-1s and contraception.

Oral semaglutide (Wegovy tablets)

Status

The MHRA approved oral semaglutide for weight management on 11 June 2026, making it the first GLP-1 tablet licensed for weight loss in the UK. It is licensed for adults with obesity, or with overweight and at least one weight-related condition, alongside diet and activity.

How it is taken

According to the UK approval announcement, the tablet is taken once daily, starting at 1.5mg and increasing through 4mg and 9mg to 25mg, with at least a month at each step. It must be swallowed whole on an empty stomach with only a sip of water, and food, drink and other oral medicines should be avoided for 30 minutes afterwards. Check the current SmPC and patient leaflet for exact instructions.

Evidence

In the OASIS 4 trial, published in 2025, oral semaglutide 25mg produced average weight loss of around 14% over 64 weeks, compared with around 2% on placebo.

NHS status

At the time of writing, oral semaglutide was not available on the NHS for weight management and NICE had not published guidance. Rybelsus, another oral semaglutide product, is licensed only for type 2 diabetes and is not interchangeable with Wegovy tablets. See our guide to oral semaglutide and our guide to Rybelsus and weight loss.

Orforglipron (Foundayo)

Status

The MHRA approved Foundayo (orforglipron) on 10 August 2026, the first approval of this medicine in Europe. It is licensed for weight management in adults meeting BMI criteria, and for improving blood glucose control in type 2 diabetes.

How it works

Orforglipron is a GLP-1 receptor agonist, but it is a small molecule rather than a peptide. That means it can be absorbed from a tablet without fasting, and it can be taken at any time of day with or without food.

Evidence

In its phase 3 weight management trial, published in the New England Journal of Medicine in September 2025, the highest dose produced average weight loss of around 11% over 72 weeks, compared with around 2% on placebo.

Availability

At the time of writing, Foundayo was not available on the NHS. NICE guidance was in development, and Eli Lilly had not confirmed UK launch details publicly. See our guide to Foundayo.

Naltrexone-bupropion (Mysimba)

Mysimba combines two older medicines: naltrexone, used for alcohol and opioid dependence, and bupropion, used for smoking cessation and depression. Together they act on appetite and reward pathways in the brain. It has a UK licence for weight management in adults meeting BMI criteria.

However, NICE TA494 (2017) did not recommend it for use on the NHS, citing uncertainty about long-term effectiveness and cost-effectiveness. It may be available privately in some circumstances. It has several important cautions, including seizures, raised blood pressure and mental health effects, and interacts with many medicines. Supply and availability may vary; a prescriber can advise.

Setmelanotide (Imcivree)

Setmelanotide is used only for obesity caused by specific rare genetic conditions, such as POMC or LEPR deficiency, which disrupt the brain's appetite signalling. NICE HST21 (2022) recommends it in highly specialised settings for people aged six and over with these conditions. It is not a treatment for common obesity.

Medicines that are not licensed for weight loss

Some medicines are sometimes discussed in relation to weight loss but are not licensed for it in the UK:

• Ozempic (semaglutide) is licensed for type 2 diabetes only. See Ozempic vs Wegovy.
• Rybelsus (oral semaglutide) is licensed for type 2 diabetes only.
• Metformin is a diabetes medicine and may lead to modest weight loss in some people, but it is not licensed for weight management.
• Topiramate and phentermine are used in combination for weight loss in some other countries but are not licensed for weight management in the UK.
• "Fat-dissolving" injections and slimming supplements are not licensed weight loss medicines.

Investigational medicines such as retatrutide, CagriSema and amycretin were not licensed in the UK at the time of writing. Products sold online claiming to contain them are unlicensed, and their content cannot be verified. See our guide to the GLP-1 pipeline.

Comparing the options

Trial comparisons are approximate. Different trials enrolled different people and lasted different lengths of time, so the figures are not directly comparable unless from a head-to-head trial.

Injection or tablet?

Some people prefer a weekly injection, which needs no daily routine. Others prefer to avoid needles. Oral semaglutide requires a strict morning routine; orforglipron is more flexible. Our comparison of oral and injectable GLP-1s looks at the trade-offs, and our guide to weight loss tablets in the UK focuses on the tablet options.

How prescribers choose between options

There is no single right medicine for everyone. When deciding what to offer, a prescriber will typically weigh:

• Your health conditions. For example, someone with type 2 diabetes may benefit from a medicine that also lowers blood glucose, while someone with established heart disease may be offered a medicine with cardiovascular outcome data.
• Your goals. How much weight loss is needed to make a meaningful difference to your health and daily life.
• Your other medicines. Interactions, such as tirzepatide and the contraceptive pill or orlistat and levothyroxine, can influence the choice. See our guide to GLP-1 medication interactions.
• Your preferences and routine. Weekly injections, daily injections, a strict morning tablet routine or a flexible daily tablet each suit different people.
• Side effect history. If you did not tolerate one medicine, another may be considered, sometimes at a slower titration.
• Pregnancy plans. All GLP-1 medicines should be stopped before trying to conceive, with a gap that differs between medicines.
• Access and cost. What is available on the NHS locally, and what is sustainable if treatment is private.

You may also switch between medicines over time. Our guides to switching from Wegovy to Mounjaro and switching from an injection to a tablet explain how switches are usually managed.

Who can be prescribed weight loss medicines?

Licence criteria differ slightly between medicines, but for most GLP-1-based medicines they cover adults with:

• a BMI of 30 or above, or
• a BMI of 27 or above with at least one weight-related condition, such as type 2 diabetes, high blood pressure, abnormal blood fats, sleep apnoea or heart disease

NICE recommends using lower BMI thresholds for people from South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean backgrounds. NHS criteria are often stricter than licence criteria because of capacity. Our guide to who can get weight loss injections and our eligibility checker give general information, but the prescribing decision is always made by a clinician.

Reasons a medicine may not be suitable

These vary by medicine but commonly include pregnancy or planning pregnancy, breastfeeding, a history of pancreatitis, certain thyroid conditions mentioned in the product information, severe gastrointestinal disease, and some eating disorders. See our guide to who should not take GLP-1s.

NHS and private routes

NHS

NHS access depends on the medicine and where you live. Orlistat can be prescribed by GPs. Wegovy and liraglutide are usually accessed through specialist weight management services. Mounjaro is being introduced in primary care in phases. Waiting times and availability vary.

Private

Many people access treatment through regulated private providers, including online pharmacies, online doctor services and clinics. A responsible provider will carry out a full consultation, verify identity and weight, ask about your medical history and other medicines, and may ask for permission to contact your GP. Our guides to private vs NHS weight loss treatment and how to choose an online pharmacy explain what to look for.

Costs vary by medicine, dose and provider and change over time, so we do not list prices in our guides. Our price comparison explains what affects cost, and our provider comparison shows how regulated services differ in consultation, follow-up and support.

Staying safe

The MHRA has warned repeatedly about counterfeit and unlicensed weight loss products, including fake pens and so-called research peptides sold online, through social media and in beauty settings. These may contain the wrong dose, the wrong substance or harmful contaminants. Signs of an unsafe source include no consultation, no request for ID or medical history, sale through social media or messaging apps, and prices that seem far out of line. See our guides to fake weight loss jabs and who regulates online weight loss services.

For related reading, browse our medication guides, or visit our hubs for weight loss injections and oral GLP-1 tablets.

When to speak to a professional

Speak to your GP, a pharmacist or a regulated prescriber if:

• you would like to know whether a weight loss medicine might be suitable for you
• you take other regular medicines, including contraception, insulin, sulfonylureas, warfarin or levothyroxine
• you are pregnant, breastfeeding or planning a pregnancy
• you have a history of pancreatitis, gallbladder disease, an eating disorder or depression
• side effects from a current weight loss medicine are troublesome or not settling

Seek urgent medical help (call NHS 111, or 999 in an emergency) if you are taking a weight loss medicine and have:

• severe, persistent abdominal pain, which may spread to your back, with or without vomiting
• pain in the upper right abdomen with fever or yellowing of the skin or eyes
• signs of severe dehydration, such as very little urine, confusion or fainting
• thoughts of harming yourself
• signs of a severe allergic reaction, such as swelling of the face or throat, or difficulty breathing

Suspected side effects can be reported to the MHRA through the Yellow Card scheme.