Cost Comparison of Weight Loss Drugs in the UK (October 2026)

01 · The short answer

Weight loss drug costs side by side

The cost of a weight loss drug in the UK depends on the medicine, the dose and the provider.

02 · Mounjaro

What Mounjaro costs, dose by dose

Mounjaro is a once-weekly injectable made by Eli Lilly, licensed in the UK for weight management in adults and sold as a pre-filled KwikPen in six strengths.¹

Our standard prices are £169.99 at 2.5mg, £218.99 at 5mg, £279.99 at 7.5mg, £290.99 at 10mg, £319.99 at 12.5mg and £329.99 at 15mg. Per week, that is £42.50 at the starting dose and £82.50 at the top dose. All six doses are in stock.

New customers save £40 on their first order at any dose with code FIRST40, including people switching to us at a higher dose. Your first 2.5mg pen therefore costs £129.99 (standard price £169.99), and switching at 15mg means a first order of £289.99. After that, an automatic £25 reorder discount applies to every future order (code DOSE25). The current values are shown live; see our Mounjaro discount code page for the detail.

Across the UK pharmacies we track, the cheapest and dearest 2.5mg starting pens are £143.96 and £179.99. For the same dose, the gap between providers ranges from £27 to £41. Boots' Mounjaro doses range from £179.00 to £339.00. Those figures come from our own index, checked 11 October 2026, and they move, so check the date. Our Mounjaro price comparison shows provider-by-provider detail.

03 · Wegovy

Which is cheaper, Wegovy or Mounjaro?

At the starting dose, a first Wegovy pen is £99.99 as a first-order price, against £129.99 for a first Mounjaro 2.5mg pen. The difference that matters comes later, because the two ladders are built differently.

Wegovy comes as 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg pens. You step up after 4 weeks on each of 0.25mg, 0.5mg, 1mg and 1.7mg, so the 2.4mg maintenance dose starts from week 17.¹⁸ Mounjaro also starts at 2.5mg and steps up in 2.5mg increments after at least 4 weeks on each dose, depending on how you respond, and many people settle at 5mg, 10mg or 15mg.

Price is only half the picture. In SURMOUNT-5, the first large head-to-head trial, adults on tirzepatide lost on average 20.2% of body weight over 72 weeks versus 13.7% on semaglutide 2.4mg (Wegovy). Both are effective licensed treatments, and the better fit depends on your health profile, tolerance and prescriber advice.¹⁵ Trial averages do not predict your own result.

04 · Planning

What a year of Mounjaro costs

A first year of Mounjaro costs £2,711.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,599.88 if you step up through every dose to 15mg, at standard prices. That covers 52 weeks, or 13 pens. A new customer's first order is £40 less, and every later order is £25 less.

Payment can be spread: we accept Visa and Mastercard, Klarna and pay-monthly options, with no subscriptions. The consultation is free and the price shown is the price paid, with no hidden fees. Delivery is free next-day tracked, and same-day dispatch applies when you order by 3pm.

If you want to see whether you are suitable, start your free consultation. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

05 · Cost per result

Cost per month versus cost per result

A lower monthly price is not automatically better value, because the trials show different average results.

In SURMOUNT-1, 2,539 adults on tirzepatide alongside diet and exercise lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, against 3.1% with lifestyle changes alone. For someone starting at 100 kg, 20.9% is about 21 kg. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

In STEP 1, adults on semaglutide 2.4mg (Wegovy) lost on average 14.9% of body weight over 68 weeks, against 2.4% on placebo.⁹ That trial tested a different medicine, so it is not a head-to-head with SURMOUNT-1.

SURMOUNT-5 gives the direct comparison. Over 72 weeks, 81.6% of people on tirzepatide lost at least 10% of body weight versus 60.5% on semaglutide, and 48.4% lost at least 20% versus 27.3%. Average loss was 22.8 kg versus 15.0 kg.¹⁵ Use these figures to judge what you are paying for, then discuss them with your prescriber.

06 · Tablets and alternatives

Tablets, Saxenda, orlistat and "cheaper" alternatives

There is no tablet form of Mounjaro, because tirzepatide is injection-only in the UK. Two GLP-1 weight loss tablets are now licensed: Wegovy tablets (oral semaglutide, Novo Nordisk), approved by the MHRA in June 2026, and Foundayo (orforglipron, Eli Lilly), approved in August 2026. They are different medicines with their own dosing, eligibility checks and trial results, and both are prescription-only.²⁰²¹

Check current Wegovy tablet prices on the product page, and our cost comparison of GLP-1 drugs for how the classes sit together.

Other licensed options work differently. Orlistat is a tablet that blocks some dietary fat absorption and produces smaller average losses. Saxenda (liraglutide) is a daily injection supplied at 6mg per millilitre, unlike once-weekly Mounjaro and Wegovy.

Ozempic is semaglutide licensed for type 2 diabetes. It is not a UK weight loss medicine, and prescribing it privately for weight loss is off-label. The licensed weight-management options are Mounjaro and Wegovy, so "Mounjaro vs Ozempic" is really Mounjaro vs Wegovy, and a regulated UK pharmacy will not supply Ozempic for weight loss.¹⁸

07 · Poor man's Ozempic

Is there a "poor man's Ozempic"?

The phrase is usually attached to "natural GLP-1" supplements such as berberine, and it is marketing rather than medicine. These products are low-cost supplements with no clinical oversight. They are not medicines, are not regulated for this use and have no comparable trial evidence.

Dosing is not standardised, and dramatic weight-loss claims on supplement or seller pages should be treated with caution. Low price is a reason to ask questions, not a reason to switch. Weight-loss pens sold by unverified sellers carry a separate risk.⁷

08 · Safe ways to save

Saving money without taking risks

The safe ways to lower cost are comparing dose-for-dose prices and using the new-customer and reorder discounts. Shortcuts are where cost-cutting becomes dangerous.

Counterfeits are the other cost trap. The MHRA has seized thousands of fake weight-loss pens in the UK and has issued alerts after falsified Mounjaro pens were identified. Fake pens have caused hospitalisations, and some contained insulin rather than tirzepatide. Only buy from a pharmacy you can verify on the GPhC register, never from social media, beauty salons or unverified websites. Genuine treatment always involves a prescription and a clinical consultation.⁷¹²

A genuine pen comes from a registered pharmacy with a batch number and expiry date, arrives cold-chain packaged, and the solution is clear and colourless. Do not use a pen that has been frozen, looks cloudy or discoloured, has particles, is past its expiry, or has been out of the fridge for more than 30 days in use, or has been above 30°C.¹³ Our Mounjaro comes through official LillyDirect supply, direct from Eli Lilly's UK distribution. For other supplier comparisons see online pharmacy price comparisons.

09 · NHS versus private

NHS or private: what you pay

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition. The NHS primary-care rollout began in June 2025 with the highest-need groups first, initially BMI 40+ with four or more qualifying conditions.⁴⁶

Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting. If you are prescribed on the NHS in England, the standard prescription charge of £9.90 per item applies unless you are exempt. NHS access to Wegovy runs through specialist weight-management services; ask your GP.

Licensed private use means a BMI of 30 or above, or between 27 and 30 with at least one weight-related condition such as high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes, alongside a reduced-calorie diet and more activity.¹ A prescriber assesses your BMI, medical history and current medicines first.

10 · Stopping, switching, safety

Why people stop, and switching on cost

People stop Wegovy for many reasons, and cost is only one. In STEP 1, gastrointestinal side effects were reported by 74.2% of people on semaglutide 2.4mg against 47.9% on placebo, and 7.0% stopped treatment because of side effects versus 3.1% on placebo.⁹ Tolerance matters as much as price.

If you are considering a switch from Wegovy or Ozempic to Mounjaro, there is no licensed direct conversion. Switching is done under prescriber supervision: typically the previous medicine is stopped, a washout interval is observed, and Mounjaro is started at a dose your prescriber judges appropriate, often the 2.5mg starting dose. Never run two GLP-1 medicines together.

Mounjaro must also not be combined with other GLP-1 medicines, unlicensed "research" peptides such as retatrutide (which has no UK licence) or compounded copies. These have no safety data and no regulated supply chain. If something promises faster results outside a licensed pathway, treat that as the warning sign.

Tell your prescriber about everything you take. If you use insulin or sulfonylureas, doses may need adjusting because of the risk of low blood sugar. Report any new symptom through the Yellow Card scheme.

11 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹

12 · Ordering with us

How ordering works

Ordering takes four steps, and the consultation costs nothing.

• Free online consultation: a short health questionnaire with no charge and no obligation.
• Prescriber review: a GPhC-registered prescriber reviews it, not a scoring script. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• Dispensing and dispatch: our registered pharmacy dispenses, with same-day dispatch when you order by 3pm.
• Delivery: free next-day tracked delivery in discreet, temperature-controlled packaging. Saturday delivery is £14.99.

Ongoing monthly reviews, dose titration and side-effect support are part of the service, and repeat orders re-check suitability with no auto-shipping. Needles, a sharps bin and injection guidance come with every order, and our free GLPTrackr app helps you track your journey. Browse all weight loss treatments, or compare against weight loss medication prices and injection price comparisons. Prescription-only medicines are supplied after consultation; individual results vary, and this page is information, not a substitute for medical advice.