Weight loss medications in the UK: a 2026 overview

Prescription weight loss medicines have moved from a niche tool into one of the most discussed treatments in UK community pharmacy. If you've spent any time on the news or social media, you've probably heard about Mounjaro and Wegovy — but you've also probably heard a lot of conflicting information about who they're for, how they work, and how to get them safely.

This article is a plain-English overview from a pharmacist's perspective. We won't tell you which medicine is right for you — that's a conversation for a real consultation, not a blog post — but we'll give you a clear, honest picture of what's available in the UK in 2026 and how the assessment process works.

The five medicines currently licensed in the UK

As of 2026, five prescription weight loss medicines are licensed for use in the UK:

• Mounjaro (tirzepatide) — a once-weekly injection
• Wegovy (semaglutide) — a once-weekly injection
• Saxenda (liraglutide) — a once-daily injection
• Mysimba (naltrexone/bupropion) — daily oral tablets
• Orlistat (also sold as Xenical or Alli) — oral capsules with meals

They are not equivalent. They work through different mechanisms, suit different patients, and carry different side-effect profiles. The most-talked-about three — Mounjaro, Wegovy and Saxenda — all belong to a family called GLP-1 receptor agonists, which act on hunger and appetite signalling in the gut and brain. Mounjaro additionally acts on a second receptor (GIP), which is part of what distinguishes it.

How the GLP-1 medicines work — visualised

The result of this longer-lasting signal: most people feel full sooner during a meal and stay fuller for longer between meals. Combined with lifestyle changes, that often translates into reduced calorie intake over time. Mysimba works on a completely different pathway (combining naltrexone, used in addiction medicine, with bupropion, used in depression and smoking cessation), and Orlistat works at the gut level by blocking some of the fat in food from being absorbed.

Who is eligible — in general terms

Eligibility is the most important and most misunderstood part of these medicines. UK clinical criteria (broadly aligned with NICE guidance) typically require:

• A BMI of 30 or above, or
• A BMI of 27 or above with at least one weight-related health condition — for example type 2 diabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease
• Aged 18 or over
• Able to attend an in-person or video consultation for height and weight verification
• Willing to commit to ongoing follow-up

Specific eligibility criteria vary by medicine. The exact thresholds and exclusions are set out in each medicine's Patient Group Direction (PGD) and Summary of Product Characteristics (SPC), and the pharmacist will work through them with you at consultation.

How they compare at a glance

This table is just a starting point. It doesn't say which is "best." Some patients can't take a GLP-1 medicine because of personal or family medical history — in which case Mysimba or Orlistat might be the better option. Others find injections impractical and prefer an oral approach. The right answer for any individual depends on their clinical picture, lifestyle, and budget.

Side effects to be aware of

Most side effects across this class of medicines are mild and gastrointestinal — nausea, diarrhoea or constipation, reduced appetite, occasional reflux. These tend to settle as the body adjusts and as the dose is gradually increased.

Less common but more serious side effects can occur and require urgent medical attention:

• Severe abdominal pain (possible pancreatitis)
• Signs of allergic reaction (swelling, breathing difficulty)
• Vision changes in patients with pre-existing diabetes
• Gallbladder problems

Every patient who starts on one of these medicines should be given the full patient information leaflet and clear guidance on when to seek help. We always run through this at the initial consultation and again at follow-up.

The consultation process at Hyde Park Pharmacy

The process for any of these medicines at our pharmacy follows the same structure:

1. Get in touch — message us on WhatsApp, call, or pop in.
2. Initial consultation — in person or by video. We verify your identity, measure or confirm your height and weight, and review your medical history.
3. Clinical decision — the pharmacist decides if treatment is clinically appropriate. If it is, we explain the cost and dispense the medicine. If it isn't, we explain why and discuss alternatives.
4. Ongoing support — monthly follow-up consultations to monitor progress, side effects, and dose adjustments.

We don't take payment before the pharmacist has agreed treatment is right for you. That's a deliberate choice — paying first creates pressure on both patient and pharmacist that we want to avoid.

One thing to be wary of online

The MHRA has issued repeated warnings about counterfeit GLP-1 injections being sold online — particularly via social media or marketplace listings offering "Mounjaro" or "Ozempic" at unusually low prices. These are dangerous. Always check that any UK pharmacy you order from is registered with the General Pharmaceutical Council and that they require a real clinical consultation. You can verify any UK pharmacy on the GPhC public register.

Hyde Park Pharmacy is GPhC-registered, premises number 9011727. All medicines we supply are sourced through licensed UK wholesalers.

This article is general information and does not replace personal medical advice. Always consult a qualified healthcare professional before starting any new treatment. If you experience side effects from a medicine, report them via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk. Last clinically reviewed: 30 May 2026.