Cheapest 5mg Mounjaro Pen in the UK? Prices Compared (October 2026)

01 · Comparison

How to compare 5mg pen prices like for like

Compare the same dose, the same quantity and the full cost to your door.

If you want a longer look at the starting dose, our Mounjaro 2.5mg injection price guide covers the first pen. For other pages on this dose, see our guides to cheap Mounjaro 5mg and the Mounjaro 5mg pen.

02 · Ordering

How ordering a 5mg pen works

Ordering takes four steps. If you are switching to us from another provider at 5mg, your first order still gets the new-customer discount.

• Free online consultation. A short health questionnaire with no charge and no obligation. Start your free consultation.
• Prescriber review. Your answers are reviewed by a GPhC-registered prescriber, 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 your pen, with same-day dispatch when you order by 3pm.
• Delivery. Free next-day tracked delivery by DPD in temperature-controlled, discreet packaging. Needles, a sharps bin and injection guidance come with every order.

Our supply comes through official LillyDirect, direct from Eli Lilly's UK distribution. The prescribing team also provides monthly reviews and dose-titration support. If you would like to read more before deciding, the guide to buying a Mounjaro 5mg pen walks through the same process.

03 · What a 5mg pen is

What a 5mg Mounjaro pen actually is

Mounjaro is the brand name for tirzepatide, a once-weekly injectable prescription medicine made by Eli Lilly. In the UK it is licensed for weight management in adults and for type 2 diabetes. It comes as a pre-filled multi-dose pen, the KwikPen, in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹ A 5mg pen therefore delivers 5mg of tirzepatide per weekly injection, and each pen holds four weekly doses.¹ That is why a pen is priced as a four-week supply. You can read more in our guide to how many doses are in a 5mg Mounjaro pen.

The 5mg pen is not where anyone starts. Everyone begins on 2.5mg once a week. That starting dose is about letting your body adjust, not about weight loss itself. After at least four weeks the dose increases to 5mg. From there it can step up by 2.5mg at a minimum of four-week intervals (7.5mg, 10mg, 12.5mg) to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹ Many people settle at a maintenance dose of 5mg, 10mg or 15mg. Higher is not automatically better, and your prescriber will guide the right pace.

Because the 5mg pen is the first step up from the starter pen, it is also the dose where people compare prices most. They have finished a first pen, know the process and want to keep the cost sensible. That is a reasonable thing to do, as long as the pen you buy is a genuine, prescribed one.

The way tirzepatide works explains why the dose ladder moves gradually. It 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. In practice most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹ It is the dual action that sets it apart from single-action medicines such as semaglutide.

Our live price for each strength is on the Mounjaro product page.

Finally, a note on what the pen is not. It is not a flexible container you can divide up to make a month last longer. The pen is designed and licensed to deliver exactly four weekly doses, and the dial will not let you set a dose larger than the medicine remaining inside.

04 · Why prices differ

Why 5mg pen prices differ between pharmacies

Prices differ because each pharmacy sets its own margin, discount and delivery terms on the same Lilly-supplied pen. Eli Lilly announced a UK list-price increase for Mounjaro on 14 August 2025, effective 1 September 2025. Pharmacy sell prices vary because of confidential discounts, so the list price is a starting point, not what you will pay.

This is why a single "cheapest" figure goes out of date quickly. Our own index of the UK pharmacies we track found a spread between providers for the same dose of between £20 and £36.03 (checked 25 October 2026). Across all doses and providers, pens run from £143.96 to £319.99. Those figures cover every strength, so they should not be read as a 5mg price. For 5mg, our standard price is £189.99, and you should look up the 5mg price at any other provider directly.

• Introductory prices. Many sellers show a low first-pen price that rises on later orders. We make our own structure plain: a new-customer discount on the first order, then a reorder discount on every future order.
• Bundles. A multi-pen bundle can look cheaper per month but commits you to a dose before your prescriber has agreed it. Dose changes are decided by response and tolerance, not by the bundle.
• Delivery and fees. Add any delivery or consultation charge to the pen price before you compare. Our consultation is free and standard delivery is free next-day tracked.
• Dating. Check the date on the price. Prices in forum posts and social media threads can be out of date within days. Ours are checked and dated, with the date shown as 25 October 2026.

It is also worth separating "cheapest" from "best value". A pen priced a little higher but supplied directly through LillyDirect, with a prescriber who reviews you each month, may suit you better than a cheap pen from a seller you cannot verify.

Our lowest-price 5mg Mounjaro page and the guide to single-pen 5mg Mounjaro pricing show the same checks from other angles, which can be handy if you are comparing several offers side by side.

Payment can change what feels affordable even when the pen price is the same. We accept Visa and Mastercard, Klarna and pay-monthly options, and there are no subscriptions, so you only order when you and your prescriber agree you need the next pen.

05 · A year of costs

What a year on Mounjaro costs if you settle at 5mg

If you settle at 5mg, the first 52 weeks cost £2,399.88 at standard prices, which is 13 pens. If you settle at 15mg, the same year costs up to £3,279.88. Those two figures bracket the range for the first year, and both are before discounts. A new customer's first order is £40 less, and every later order is £25 less.

The first year always includes the climb up the dose ladder. If you step up after 4 weeks on each dose, your first four pens (2.5mg to 10mg) cost £879.96 at standard prices. Your prescriber decides based on how you respond and tolerate each dose.¹

The 12.5mg pen is £289.99 per month.

A few planning points follow from this.

• Budget for the dose you will probably be on, not just the one you start on. The monthly cost changes as the dose climbs.
• Think about what happens when you stop. Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4–5 weeks to clear the system.¹ That is useful for planning a last pen, and nothing needs doing while it clears.
• Use the reorder discount. Every later order is £25 off the standard price, and it applies automatically (code DOSE25).

06 · What 5mg delivers

What results to expect at the 5mg dose

In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg over 72 weeks. That compares with 3.1% with lifestyle changes alone.² At 72 weeks, 85% of participants on 5mg had lost at least 5% of their body weight.² These are trial averages. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

As a worked example, for someone starting at 100 kg, 15% is about 15 kg. That is straight arithmetic on the trial average, not a prediction for you, because trial averages do not predict your own result. The same trial reported 19.5% on 10mg and 20.9% on 15mg, and these were separate dose groups. Many people settle at a maintenance dose of 5mg, 10mg or 15mg, and your prescriber will guide the right pace.

Weight loss on Mounjaro is gradual by design. The first weeks on 2.5mg are an adjustment phase and losses are usually modest. Most measurable progress builds from 5mg onward, month by month. The trial measured results at 72 weeks, so think in months, not days, and judge progress by trend, not individual weigh-ins.¹ Early loss includes water weight, so the trend over weeks matters more than a single weigh-in.

Your prescriber reviews how treatment is going. If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, they will discuss whether continuing or stopping is right for you.¹ That review is the basis for deciding about dose, and price should come second.

Side effects are worth knowing about too. The commonest early effects are mild nausea, altered appetite and tiredness in the first days after each injection, and they usually settle.¹ If you notice anything unexpected, speak to your prescriber, and you can also report it through the Yellow Card scheme.⁷

Our weight loss treatments overview sets Mounjaro alongside the other options if you are still deciding which medicine suits you.

07 · Avoiding fake pens

Avoiding counterfeit pens when you chase a low price

The lowest price is the most dangerous thing to chase if the seller cannot be verified. 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.⁷ 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.¹²

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. Ours comes through official LillyDirect, direct from Eli Lilly's UK distribution, and our GPhC registration number is 9012878.

When your pen arrives, check it against this list.

• It comes from a registered pharmacy and shows a batch number and an expiry date.
• It arrives cold-chain packaged.
• The solution inside is clear and colourless.
• It has not been frozen, and it is not cloudy, discoloured or full of particles.
• It is within its expiry date, and an in-use pen has not been out of the fridge for more than 30 days, or above 30°C.

If supply or packaging ever seems wrong, check the pharmacy on the GPhC register and contact the pharmacy before injecting.¹³

Some red flags apply to any seller. A seller offering to supply without a consultation or prescription is not operating legally. A seller who moves the conversation to a messaging app, or who cannot tell you the pharmacy's registration number, should be avoided.

Each pen is designed and licensed to deliver exactly four weekly doses, so use the pen as designed, then dispose of it.¹

You can also compare our registered-pharmacy listing on cheapest 5mg Mounjaro from a UK registered pharmacy.

08 · NHS and private

NHS or private: the honest picture for a 5mg pen

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.

For NHS prescriptions in England, the standard prescription charge is £9.90 per item. Whether that applies to you, and whether you qualify for NHS-supplied Mounjaro at all, is a matter for your GP or the relevant NHS service. The NHS tirzepatide guide sets out how the medicine is used on the NHS.⁵

The licensed criteria for private prescribing are separate from NHS eligibility. 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. Examples are 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. A prescriber will assess your BMI, medical history and current medicines before deciding whether it is suitable for you.¹

What about people with diabetes? Mounjaro is licensed for type 2 diabetes as well as weight management.¹ Whether a person with diabetes can get it on the NHS depends on local pathways and on the criteria their clinical team applies. The first step is to ask your GP or diabetes team. If you take insulin or a sulfonylurea, tell the prescriber, because those doses may need adjusting because of the risk of low blood sugar.

Treatment length is decided with your prescriber and reviewed over time.

Private treatment is therefore a choice that sits alongside the NHS rather than against it. If you qualify for NHS treatment and can access it, that is a legitimate route. If you do not, or cannot wait, a regulated online pharmacy offers a prescriber-led route with transparent pricing. You can see how we handle this on our 5mg Mounjaro availability page.

09 · Using the pen

Using a 5mg pen: injecting, missed doses and storage

Mounjaro is injected under the skin once a week, on the same day each week, at any time of day, with or without food.¹ The licensed injection 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, because Mounjaro works the same morning or evening, so pick a day and time you will remember. Many people choose a weekend morning so early side effects fall on days off. Our walkthroughs on how to use a 5mg Mounjaro pen and how to inject the Mounjaro 5mg pen go step by step.

The pen is set by turning the dose knob until the dose indicator shows the correct dose in the window. Follow the pen's instructions for the injection itself.

If you miss a dose, take it as soon as you can within four days (96 hours) of the scheduled time, then carry on with your usual day. If more than four days have passed, skip the missed dose entirely and take the next one on your normal day. Never take two doses within three days of each other. You can change your injection day if at least three days (72 hours) have passed since your last dose.

Storage is the part people most often ask about. Keep pens in a fridge at 2–8°C and never freeze them. Once in use, a pen can be kept out of the fridge not above 30°C for up to 30 days, which is useful for short trips, after which it should be discarded. Keep the cap on to protect the pen from light, and never use a pen that has been frozen.

Travelling is straightforward. You can fly with Mounjaro, carrying pens in hand luggage because hold luggage can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription. Most holidays need no special arrangements, and for hot climates an insulated pouch helps. Check destination rules for travelling with prescription injectables before you fly.

Unopened pens should be kept in the fridge and 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 day limit you remember. Figures circulating online often come from other countries' labels. The patient information leaflet and our pharmacy team are the right places to check.¹³

In the first weeks on any dose, mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle. Some people notice a change in appetite in week one, and others feel little until a higher dose. Both are normal. If you are concerned, our support team is available Monday to Friday, 9am to 5pm, on 0333 207 0413 or at support@everydaymeds.co.uk.

10 · Saving without risk

Ways to keep the cost of 5mg down without cutting corners

The safe ways to reduce what you spend are the discounts, the dose your prescriber agrees on and the way you pay. They do not involve altering how you use the pen. The new-customer discount is £40 off your first order at any dose with code FIRST40. That includes people switching to us at 5mg or at a higher dose from another provider. Every later order gets an automatic £25 off (code DOSE25).

Spreading the cost can help. Klarna and pay-monthly options are available, and there are no subscriptions. Repeat orders re-check suitability and nothing ships automatically, so you never pay for a pen you did not choose to reorder.

If you are weighing up whether 5mg is the right place to stay, these are the points to take to your monthly review.

• How your weight trend looks over several weeks, not a single weigh-in.
• Whether side effects are manageable at 5mg.
• Whether your appetite is controlled enough on this dose to continue supporting your diet and activity changes.

You can also lean on tools that cost nothing. GLPTrackr is our free companion app for tracking a GLP-1 journey on iOS and Android, so you can show your prescriber a clear trend. We also include ongoing monthly clinical reviews, dose-titration and follow-up assessments.

Finally, if you are not sure whether Mounjaro is right for you, the consultation is free with no obligation. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. The prescription medicine itself cannot be returned once dispensed, except if it is faulty, damaged or the wrong item. Contact us within three days if that happens, and refunds take 5–10 working days. Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. This page is information, not a substitute for medical advice.

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