Prescription weight loss in the UK: treatments, eligibility and costs

If you are searching for prescription weight loss in the UK, you are probably weighing up a handful of overlapping options: the NHS route with its long waits, private online pharmacies, and the growing list of medicines with names like Mounjaro, Wegovy and, soon, oral tablets. This guide explains what "prescription weight loss" actually means in Britain today, which treatments exist, who qualifies, roughly what it costs, and how to tell a properly regulated service from a risky one.

The short version: the leading treatments are GLP-1 medicines, they are prescription-only, and no legitimate UK service will sell them without an online consultation and a clinical assessment by a prescriber first. Everything below fills in the detail so you can make an informed choice.

What "prescription weight loss" means in the UK

Prescription weight loss refers to licensed medicines used to treat overweight and obesity as a medical condition, prescribed and supervised by a healthcare professional. It is not the same as over-the-counter diet pills, food supplements or anything you can add to a basket without a consultation.

The most talked-about treatments belong to a class called GLP-1 receptor agonists. In simple terms, these medicines mimic gut hormones your body already makes after eating. They slow how quickly your stomach empties and act on appetite centres in the brain, so you feel fuller for longer and think about food less. For many people, obesity is driven by hunger and satiety signalling rather than a shortage of willpower, which is why medicines that adjust those signals can help where diets alone have not.

Two points matter before we go further. First, these are genuine medicines with genuine risks, not a shortcut. They are licensed for use alongside a reduced-calorie diet and increased physical activity, not instead of them. Second, they are prescription-only medicines. In the UK, a GLP-1 weight-loss treatment can only be supplied after an online consultation and a clinical assessment by a prescriber who confirms it is appropriate and safe for you. If a website offers to sell you the medicine with no consultation, that is a red flag to walk away.

Which prescription weight-loss treatments are available?

There are two main injectable GLP-1 treatments licensed for weight management in the UK, plus emerging oral options. Here is how they compare.

A few things to read carefully in that table. The percentages are averages from named clinical trials at the highest maintenance dose, taken alongside diet and activity support. They are not promises. Individual results vary a great deal, and some people lose less, some more.

Mounjaro (tirzepatide)

Mounjaro is currently the only dual-action treatment of the two, acting on both the GLP-1 and GIP receptors. In the SURMOUNT-1 trial, participants without diabetes taking the 15mg dose lost around 22.5% of their body weight on average over 72 weeks, alongside lifestyle changes. That dual mechanism is why many clinicians see it as the more powerful option for total weight loss, though "more powerful" is not automatically "more suitable" for every person, and results vary from person to person.

Mounjaro is started low and increased slowly. The starting dose is 2.5mg once weekly, increased by 2.5mg at intervals of at least four weeks, up to a maximum of 15mg. This deliberate build-up, called titration, gives your digestive system time to adjust and reduces side effects. If you want the full picture, our guides on who qualifies for Mounjaro and the Mounjaro dosage and titration schedule go deeper.

Wegovy (semaglutide)

Wegovy is a single-hormone GLP-1 receptor agonist and one of the most extensively studied weight-loss medicines available. In the STEP-1 trial, adults without diabetes taking the 2.4mg dose lost around 14.9% of their body weight on average over 68 weeks, alongside lifestyle support. Like Mounjaro, it is titrated: everyone starts at 0.25mg once weekly and steps up gradually. That induction dose is a clinical safeguard, not an optional extra.

For a direct head-to-head, our Mounjaro vs Wegovy comparison breaks down the differences in mechanism, results and suitability.

Oral tablets: what's coming

Injections do not suit everyone, and oral GLP-1 options are the fastest-moving part of this field. Oral semaglutide and a non-peptide tablet called orforglipron (which The Weight Clinic lists as Foundayo) are examples of where treatment is heading. Availability and licensing for weight loss are still evolving, so check current status rather than assuming a tablet is available. Our Wegovy Tablet guide and the article on whether an oral weight-loss tablet exists yet cover the specifics as they stand.

You can see the full range of injectable options on our weight-loss injections page, or browse all treatments in one place.

Who qualifies for prescription weight loss in the UK?

Eligibility is a safety boundary, not a formality. These medicines are for people whose weight is putting their health at risk, not for losing a few pounds before an event.

The licensed criteria for GLP-1 weight-loss treatment, set out in each medicine's Summary of Product Characteristics (the regulated product information approved by the Medicines and Healthcare products Regulatory Agency), are broadly:

• A BMI of 30 or above, or
• A BMI of 27 or above if you also have a weight-related health condition, such as type 2 diabetes, high blood pressure, high cholesterol, obstructive sleep apnoea or non-alcoholic fatty liver disease.

It is worth separating two things that often get confused. The licensed criteria above, which come from the product's licence, are what a private prescriber assesses against. The NHS funding criteria are stricter and are set separately by NICE for NHS-commissioned services, which is why NHS access typically requires a higher BMI plus a comorbidity and often a specialist referral. If you have been turned away by the NHS on funding grounds, you may still meet the licensed criteria a private pharmacy prescribes against. Our guide to a safe NHS alternative for weight loss explains that route.

BMI is a starting point, not the whole story. A prescriber also reviews your medical history, current medicines and individual risk, because the number on the scale does not capture everything. You can get an indication with an online eligibility check in a few minutes.

When prescription weight loss is not suitable

A responsible service will decline some applications outright. GLP-1 treatment is generally not appropriate if you:

• Have a personal or family history of medullary thyroid cancer, or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
• Have had severe or recurrent pancreatitis
• Are pregnant, trying to conceive, or breastfeeding
• Have type 1 diabetes
• Are under 18
• Have a BMI in the healthy range with no clinical need

If your application is declined, that is the system working as intended. Safety should always take priority over making a sale.

NHS versus private online clinics

Both routes are legitimate. They suit different situations.

The NHS route is free but access is limited and waits can be long, often via a Tier 3 specialist weight-management service. A regulated private pharmacy offers faster access and more flexibility, but "private" must never mean "unregulated." The danger zone is unregistered sellers, usually based abroad, offering suspiciously cheap medicine with no consultation. That medicine may be counterfeit, incorrectly stored, or unsafe, and there is no clinical accountability if something goes wrong. Our guide to getting weight-loss treatment without a GP covers how to navigate the private route safely.

How to spot a properly regulated service

Before you hand over any details or money, check for these markers:

• A GPhC registration. A UK online pharmacy must be registered with the General Pharmaceutical Council, with a registration number you can verify on the GPhC register. No number, no trust.
• A real clinical consultation. A UK-registered prescriber must review your history and approve treatment. If you can complete a "purchase" without any clinical questions, it is not a medical service.
• Named, registered clinicians. You should be able to see who is responsible for your care.
• Cold-chain delivery. GLP-1 medicines are proteins that degrade if they get too warm. They should arrive in insulated, temperature-controlled packaging, not a padded envelope.
• Transparent pricing and safety information. Balanced information about side effects and contraindications, not just marketing.

At The Weight Clinic, our clinical team includes Superintendent Pharmacist Andrew Lane and Pharmacist Independent Prescriber Fatma Al Sibahi, with content reviewed by Pharmacist Independent Prescriber Ali Al Sibahi. You can read more in our overview of how a remote consultation works.

What does prescription weight loss cost?

Private pricing depends on the medicine and your dose, which increases as you titrate up. At The Weight Clinic:

• Mounjaro starts from £125 per month.
• Wegovy is £115 per month standard, with £35 off your first order using code NEWME, bringing the first month to from £80.
• The eligibility check is free, and there is no subscription to lock into.

Prices cover the medicine, the prescriber's clinical review and cold-chain delivery. Because costs shift as your dose changes, always check the current figures on the treatment pages before you commit.

Managing expectations: results, plateaus and side effects

Clinical weight loss is a marathon, not a sprint, and it rarely moves in a straight line. Expect an initial drop, then periods where the scale stalls as your body recalibrates. A plateau is not failure and usually does not mean the medicine has stopped working; during those weeks, non-scale wins like better energy, sleep and how clothes fit are worth tracking. Staying on treatment at the right dose is what drives long-term results, not rushing to a higher dose.

Side effects and safety

The most common side effects of GLP-1 treatments are gastrointestinal: nausea, indigestion, constipation or diarrhoea, and fatigue, especially in the early weeks and after each dose increase. Most are mild and settle. Eating smaller, lower-fat meals and staying hydrated helps.

More serious but rare side effects include pancreatitis (inflammation of the pancreas) and gallbladder problems such as gallstones. Seek urgent medical advice if you develop severe, persistent abdominal pain, particularly if it spreads to your back or comes with vomiting. Because rapid weight loss can affect muscle as well as fat, adequate protein and some resistance exercise are worth building in.

If you experience a side effect from any medicine, you can report it through the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk. Reporting helps the Medicines and Healthcare products Regulatory Agency monitor the safety of these treatments. For medicine-specific detail, see our guides on Mounjaro side effects and Wegovy side effects. None of this is a substitute for advice from your own prescriber.

How it works at The Weight Clinic

Getting started is straightforward, but every step exists for a clinical reason:

1. Free online eligibility check. You share your height, weight, medical history and current medicines.
2. Clinical assessment by a prescriber. A UK-registered prescriber personally reviews your information; there are no automated approvals.
3. Prescription and cold-chain delivery. If treatment is appropriate, your medicine is dispensed and sent in temperature-controlled packaging.
4. Ongoing support. You start at the lowest dose and titrate up under supervision, with your clinical team available if you have concerns.

Ready to see where you stand? You can check your eligibility in a few minutes, with no obligation and no subscription.

The bottom line

Prescription weight loss in the UK is a regulated medical pathway, not a quick fix. The leading treatments, Mounjaro and Wegovy, have strong trial evidence but real risks, work best alongside diet and activity, and are only ever supplied after a proper consultation and clinical assessment. Choose a GPhC-registered service, understand the eligibility criteria, and treat the medicine as one part of a long-term plan rather than the whole answer.