Cheapest Weight Loss Pen UK: Real Costs Compared (October 2026)

01 · Costs

What a weight loss pen costs in the UK right now

The honest answer is that it depends on which pen and which dose. Across the UK pharmacies we track (checked 26 October 2026), the cheapest and dearest Mounjaro pens at any dose run from £143.96 to £319.99 per month. The smallest gap between providers for the same dose is £20, and the largest is £36.03. That spread is why it pays to compare the same strength rather than headline 'from' prices.

The Mounjaro pen at EverydayMeds costs £169.99 for the 2.5mg starter, £189.99 at 5mg, £244.99 at 7.5mg, £274.99 at 10mg, £289.99 at 12.5mg and £299.99 at 15mg. Each is the standard price for one four-week pen. Your first 2.5mg pen costs £129.99 with code FIRST40. Switching to us at 15mg? Your first order is £259.99. After that, every later order is £25 off the standard price (code DOSE25). All six doses are in stock. The consultation is free and the price shown is the price paid.

If you want to compare providers in more depth, our guides to the lowest-price weight loss injections and the monthly cost of injections set the figures side by side. For Mounjaro specifically, see our low-cost Mounjaro pen page.

02 · Compare

Weight loss pens compared: what you are actually choosing between

Three kinds of prescription weight loss injection are sold in the UK, and they are not interchangeable.

Dosing frequency affects real cost and convenience. Liraglutide is a daily injection, while Mounjaro and Wegovy are once weekly.¹ A low per-pen price on a daily product does not automatically mean a lower yearly bill, so compare on what you will actually use over a month.

03 · Ordering

How ordering works, and what the price includes

There are four steps, and none of them costs extra. First, complete a free online consultation. It is a short health questionnaire with no charge and no obligation. Second, 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. Third, our registered pharmacy dispenses it, with same-day dispatch when you order by 3pm. Fourth, you receive free next-day tracked delivery in discreet, temperature-controlled packaging. Saturday delivery is £14.99.

Needles, a sharps bin and injection guidance come with every order. Ongoing monthly reviews, dose-titration and follow-up are part of the service, and repeat orders re-check suitability, so nothing auto-ships. You can pay by Visa, Mastercard or Klarna, with pay-monthly options and no subscription. Start your free consultation to see whether a pen is suitable for you. To see how this compares with other routes, read our guide to buying weight loss pens online.

04 · Why the starting pen costs least

Why the starting pen costs least, and why that is not the whole story

The lowest-priced pen is nearly always the starting-strength one. Everyone starts Mounjaro on 2.5mg once a week.¹ That starting dose is about letting your body adjust, not about weight loss itself. So a low 'from' price tells you what the first four weeks cost, not what your treatment will cost.

The dose then steps up. After at least four weeks it rises to 5mg, and it can then climb by 2.5mg at minimum four-week intervals, through 7.5mg, 10mg and 12.5mg, to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹¹¹ At EverydayMeds the standard pen goes from £169.99 at 2.5mg to £299.99 at 15mg.

Higher is not automatically better. Many people settle at a maintenance dose of 5mg, 10mg or 15mg, and your prescriber guides the pace.¹ That matters for cost, because the dose you settle on is the main driver of your monthly bill. Someone who does well at 5mg pays £189.99 a month at standard prices. Someone who needs 15mg pays £299.99.

When comparing providers, ask these questions of any 'from' price:

• Is the price for the 2.5mg pen, or an average across doses?
• Does it assume a one-off first-order discount that disappears afterwards?
• What will the pen cost at the dose you are likely to settle on?
• Is the consultation, delivery and follow-up included, or charged separately?

Our own pricing is shown live and dated. For the discount mechanics see our Mounjaro discount code guide.

05 · Year cost planning

What a year on Mounjaro actually costs

A first year costs £2,399.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,279.88 if you step up through every dose to 15mg, at standard prices before discounts. That is 52 weeks, or 13 pens. A new customer's first order is £40 less, and every later order is £25 less. These totals are far more useful than a single pen price when you are deciding what you can afford.

If you step up after 4 weeks on each of 2.5mg, 5mg, 7.5mg and 10mg, your first four pens cost £879.96 at standard prices. Not everyone goes all the way up: your prescriber decides the pace based on how you respond and tolerate the medicine.¹

If you settle somewhere between, the monthly figure is simply that dose's price. A 7.5mg pen is £244.99, 10mg is £274.99 and 12.5mg is £289.99 at standard prices. Treat them as monthly costs to plan around.

A few planning points follow from this:

• Budget for the dose you settle on, not the one you start on. The starter pen is the smallest bill you will see.
• Plan for repeat orders. Every later order is £25 off the standard price, so ongoing cost is each dose's price less that discount.
• Spread the cost if that helps. Klarna and pay-monthly options are available, with no subscription lock-in.

Treatment is reviewed rather than open-ended. If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your prescriber will discuss whether continuing or stopping is right for you.¹ That review protects you from paying for treatment that is not working for you. For more on bundled and multi-pen costs, see our guide to weight loss injection bundles.

06 · Cost versus results

Cost versus results: what the trial data says about paying for a pen

The cheapest pen is only good value if the treatment does what you need, so it is worth looking at what the main Mounjaro trial found. In SURMOUNT-1, which enrolled 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks. People on lifestyle changes alone lost 3.1%.² These are trial averages, and individual results vary.

As a worked example, for someone starting at 100 kg, 20.9% is about 21 kg and 15% is about 15 kg.

The trial also reported how many people reached particular thresholds. At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20% of their body weight.² Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

What does this mean for price? A few honest points:

• Time horizon matters. The trial measured results at 72 weeks. Weight loss on Mounjaro is gradual by design, so think in months, not days.¹
• The starting weeks are an adjustment phase. Losses on 2.5mg are usually modest, and most measurable progress builds from 5mg onward.
• Higher is not automatically better. Many people settle at a maintenance dose of 5mg, 10mg or 15mg, and your prescriber will guide the right pace.
• Judge by trend. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in.

If you are deciding between a weekly and a daily pen, your prescriber can talk you through the options that suit your health and budget. Our weight loss pen overview covers the options in more detail.

The takeaway for anyone hunting the lowest price: a pen that is cheap per month but does not suit you, or that you stop early, costs more per result than one you can sustain. Price per month is a starting point for the decision, not the whole decision.

07 · NHS versus private

NHS versus private: the honest picture on getting a pen

Mounjaro is available on the NHS, but access is being phased in over several years.⁴⁶ 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 people with a BMI of 40 or above and four or more qualifying conditions.⁵⁶ Full rollout is expected to take years.

But the phased approach means many people who meet the licensed criteria choose regulated private treatment rather than waiting.

Private treatment suits people who:

• do not yet meet the NHS rollout stage for their area or group,
• meet the licensed criteria but would rather start now,
• want a consultation and follow-up they can access online.

The licensed criteria for private prescribing are a BMI of 30 or above, or a BMI 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. It must be used alongside a reduced-calorie diet and increased physical activity.¹ A prescriber will assess your BMI, medical history and current medicines before deciding whether it is suitable for you.

For Wegovy, NHS access runs through specialist weight-management services; ask your GP.

A sensible approach is to ask your GP what is available locally, and compare that with the private cost over a year if you decide not to wait.

One caution: do not let cost push you towards a source that is not regulated. The NHS route is slower for many people, and a regulated pharmacy is the regulated private alternative. A very cheap pen from an unverified seller is neither.

08 · Cheap and counterfeit

When 'cheap' becomes dangerous: counterfeit pens

A price that looks too good to be true on a prescription pen should make you stop and check. The MHRA has seized thousands of fake weight-loss pens in the UK and has issued alerts after falsified Mounjaro pens were identified.⁷ 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.

Genuine UK stock is supplied through Lilly's official distribution to licensed pharmacies, and every pen carries a batch number and expiry date that can be checked.⁷ Our Mounjaro comes direct from Eli Lilly's UK distribution through official LillyDirect supply, as genuine KwikPens.

• It comes from a registered pharmacy with a batch number and expiry date.
• It arrives cold-chain packaged.
• The solution inside is clear and colourless.

Do not use a pen that has been frozen, looks cloudy or discoloured, has particles in it, is past its expiry, has been above 30°C, or has been out of the fridge for more than 30 days in use.¹³ If supply or packaging ever seems wrong, check the pharmacy on the GPhC register and contact the pharmacy before injecting.

Warning signs of an unsafe seller include:

• offering to supply without a consultation or prescription,
• selling through social media, a salon or a messaging app,
• no GPhC registration number you can look up,
• pens with no batch number, a missing or altered expiry date, or odd packaging,
• dramatic weight-loss claims that promise specific results.

Saving a modest amount on a pen is not worth the risk of injecting something that may contain the wrong medicine. Compare prices only between regulated sources. Our guide to the lowest-cost weight loss drug suppliers covers how to tell a legitimate supplier from a risky one, and our guide to weight loss pen reviews explains what to look for in provider feedback.

Remember that EverydayMeds is a GPhC-registered UK online pharmacy (registration 9012878), and you can check that for yourself. A free consultation, reviewed by a GPhC-registered prescriber, comes before any prescription is issued.

09 · Saving safely

How to lower the cost safely, and what not to do

There are legitimate ways to reduce what you pay. New customers save £40 on their first order at any dose with code FIRST40, including people switching to us from another provider at a higher dose. After that, an automatic £25 reorder discount applies to every future order (code DOSE25). Klarna and pay-monthly options can also spread the cost without a subscription.

Practical habits also stop money being wasted. Keep unused pens in the fridge and follow the leaflet. Once in use, a pen can be kept out of the fridge not above 30°C for up to 30 days, after which it should be discarded.¹ Never use a pen that has been frozen. If a pen has been out of the fridge unopened, check with the pharmacy before using it.

Following the pen's instructions is both the safest and the most economical way to use it.

10 · Eligibility and dosing

Who can use a pen, and how it is dosed

Mounjaro is licensed for weight management in adults with a BMI of 30 or above, or a BMI 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.¹ It is used alongside a reduced-calorie diet and increased physical activity. A GPhC-registered prescriber reviews your BMI, medical history and current medicines before deciding. If the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

How it works helps explain what you are paying for. Tirzepatide activates two natural gut-hormone receptors at once, GIP and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties and improve the way the body responds to insulin.¹ Most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet. Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4 to 5 weeks to clear the system.

The practical side of the weekly routine:

• Inject under the skin once a week, on the same day each week, at any time of day, with or without food.¹³
• Licensed sites are the stomach area (at least 5cm from the belly button), the front of the thigh, or the back of the upper arm if someone else gives the injection. Rotate the site with each dose.
• There is no 'best' time of day. Many people choose a weekend morning so early side effects fall on days off.
• You can change your injection day if at least 3 days (72 hours) have passed since your last dose.

If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time. If more than 4 days have passed, skip it and take the next one on your normal day. Never take two doses within 3 days of each other.¹³

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹ 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 or 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), as your prescriber may need to adjust those medicines. Experiences in the first weeks differ widely. Some people notice a change in appetite in week one, others little until a higher dose, and both are normal. Report any new symptom to your prescriber, and you can report a suspected side effect through the Yellow Card scheme.

Knowing this up front means you budget for a sensible, supervised course rather than chasing the lowest per-pen price and discovering the pen is wrong for you.

11 · Storage, travel and waste

Storage, travel and avoiding wasted pens

A pen that is stored badly is money wasted, so handling is part of keeping costs down. Keep Mounjaro pens in a fridge at 2 to 8°C and never freeze them.¹ Once in use, a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days, which is useful for short trips, and must then be thrown away. Do not use a pen that has been above 30°C. Keep the cap on to protect the pen from light, and never use a pen that has been frozen.

Unopened pens belong in the fridge until first use, and they keep until the expiry date printed on the box. If an unopened pen has been out of the fridge, check with the pharmacy before using it rather than relying on a remembered day limit. Figures circulating online often come from other countries' labels, and UK product information is what applies to you. The patient information leaflet in the box is the reference to follow.

Travelling is straightforward with planning. You can fly with Mounjaro:

• Carry pens in hand luggage, because hold luggage can fall below freezing.
• Ideally use a cool bag, with the prescription label or a copy of your prescription.
• In-use pens tolerate up to 30 days not above 30°C, so most holidays need no special arrangements. For hot climates use an insulated pouch.
• Check destination rules for travelling with prescription injectables before you fly.

Good handling also protects against supply problems. A pen that has been frozen, looks cloudy or discoloured, or has particles in it should not be used, and the pharmacy should be contacted before injecting.¹³ Our temperature-controlled, discreet packaging and free next-day tracked delivery are designed to get pens to you in the right condition. Same-day dispatch applies when you order by 3pm.

If something arrives faulty, damaged or wrong, contact us within 3 days. Dispensed prescription medicines cannot otherwise be returned, and refunds take 5 to 10 working days. Declined consultations are refunded automatically in full.

Finally, we support you after you order. Our team is available Monday to Friday, 9am to 5pm, by email at support@everydaymeds.co.uk, by chat in your account portal or by phone on 0333 207 0413. Our free GLPTrackr app helps you track your doses and progress. Ongoing monthly reviews and dose-titration follow-ups are included, and repeat orders re-check suitability. Good support reduces avoidable waste, and avoidable waste is the cheapest saving there is.