15mg Mounjaro Pen Price UK (October 2026)

01

What a 15mg Mounjaro pen costs in the UK

A 15mg Mounjaro pen costs £299.99 per month, meaning one KwikPen that contains four weekly doses. That is £75.00 per week. This is the standard price, and it is what a repeat order costs before the reorder discount. Every later order after your first is £25 off the standard price (code DOSE25), applied automatically.

If you are switching to us from another provider and already inject 15mg, your first order is £259.99 with code FIRST40. That figure is a first-order price, so the new-customer discount is already inside it. The new-customer discount applies to a first order at any dose, not only the starting pen. The consultation is free, and the price shown is the price paid, with no hidden fees. All six doses, 2.5mg to 15mg, are in stock.

Prices checked 24 October 2026.

02

What the price includes

The pen price covers the medicine itself, supplied through official LillyDirect supply, which means Mounjaro sourced directly from Eli Lilly's UK distribution. The consultation is free, and a GPhC-registered prescriber reviews every order. Needles, a sharps bin and injection guidance come with every order. Delivery is free, next-day, tracked and temperature-controlled, and we dispatch the same day when you order by 3pm. Saturday delivery is £14.99.

Ongoing monthly reviews, dose-titration and side-effect support are part of the service, so you are not left alone at a higher dose. Repeat orders re-check suitability, and there is no auto-shipping and no subscription. You can pay by Visa or Mastercard, or use Klarna and pay-monthly options.

03

Year-cost planning if you reach 15mg

Everyone starts on 2.5mg, so a first year includes lower-dose pens before any 15mg pens. The table uses standard prices before discounts. A new customer's first order is £40 less, and every later order is £25 less.

If you settle between those two, for example at 10mg or 12.5mg, work from that dose's monthly price: £274.99 or £289.99. Many people settle on 5mg, 10mg or 15mg, so you may never need the top dose. Your prescriber will guide the right pace.¹

04

How ordering works

Ordering takes three steps. First, complete the free online consultation, a short health questionnaire with no charge and no obligation. Second, a GPhC-registered prescriber reviews your consultation; payment is taken when you place the order, and if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. Third, our registered pharmacy dispenses and ships your pen, with free next-day tracked delivery.

You can also see the full range on our weight loss treatments page. Mounjaro is a prescription-only medicine supplied only after an online consultation reviewed by a GPhC-registered prescriber. Individual results vary.

Related guides: Mounjaro cliques 15mg and How many doses in mounjaro 15mg pen.

Related guide: Cheapest 15mg mounjaro.

05 · What a 15mg pen contains

What is in a 15mg Mounjaro KwikPen

A 15mg Mounjaro KwikPen is a pre-filled, multi-dose pen that holds four once-weekly doses of tirzepatide, so one pen lasts four weeks. Mounjaro is the brand name for tirzepatide, made by Eli Lilly. In the UK it is licensed for weight management in adults and for type 2 diabetes. It comes in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹

The strength is the weekly dose. Each injection is 15mg, and a pen supplies four of them.

The pen is set by turning the dose knob until the dose indicator shows the correct dose in the window. Our guide to Mounjaro clicks at 15mg explains how the dial works in practice.

How many doses you get matters when comparing prices. Each Mounjaro KwikPen contains four weekly doses. Our page on how many doses are in a 15mg pen covers this in more detail.

Supply matters too. Mounjaro is manufactured by Eli Lilly, and genuine UK stock reaches licensed pharmacies through Lilly's official distribution. Every pen carries a batch number and expiry date that can be checked. We supply through official LillyDirect supply, and all six doses are in stock.

06 · Reaching 15mg safely

How people reach 15mg: the dose ladder

Nobody starts Mounjaro on 15mg; everyone starts on 2.5mg once a week and steps up. The starting dose is about letting your body adjust, not about weight loss itself. After at least 4 weeks the dose increases to 5mg. It can then step up by 2.5mg at minimum 4-week intervals (7.5mg, 10mg, 12.5mg) to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹¹¹

The 15mg pen comes after the 2.5mg, 5mg, 7.5mg, 10mg and 12.5mg pens, with at least 4 weeks on each dose. Reaching 15mg also involves the 12.5mg pen at £289.99 before the 15mg pen at £299.99. Your prescriber sets the pace, and nothing obliges you to move up at the earliest point.

Many people settle at a maintenance dose of 5mg, 10mg or 15mg. Higher is not automatically better. If you tolerate 10mg well and your progress is steady, staying there is a legitimate clinical decision for your prescriber to make with you.

Can you take 15mg of Mounjaro?

Yes. 15mg once a week is the maximum licensed weekly dose of Mounjaro, reached only by stepping up from 2.5mg. Taking it straight away without titration is not how the medicine is licensed. A prescriber will assess your BMI, medical history and current medicines before deciding whether it is suitable for you.

Is 12.5mg strong?

12.5mg is the second-highest dose, just one step below the maximum. In SURMOUNT-1, a 72-week trial of 2,539 adults, average weight loss was 15% on 5mg, 19.5% on 10mg and 20.9% on 15mg, so results rise with dose on average, though individual results vary.² That does not mean everyone needs the top dose. The right dose is the one you tolerate and respond to.

Switching to us at 15mg

If you already take 15mg with another provider, you can move to us. Your first order is £259.99 with code FIRST40, then every later order is £25 off the standard price. Our prescribers still complete a consultation first, because repeat and switching orders re-check suitability. See our 15mg dose guide for more on this dose.

07 · What 15mg achieved in trials

What the 15mg dose achieved in the SURMOUNT-1 trial

In SURMOUNT-1, adults taking 15mg of tirzepatide alongside diet and exercise lost on average 20.9% of their body weight over 72 weeks. Adults on lifestyle changes alone lost 3.1%. The trial involved 2,539 adults. On 5mg the average was 15%, and on 10mg it was 19.5%.²

These are trial averages, and individual results vary. Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them. 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

To make the percentage concrete, here is a worked example. For someone starting at 100 kg, 20.9% is about 21 kg, and 15% is about 15 kg.

The realistic 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. Trials measured results at 72 weeks, so think in months, not days, and judge progress by trend, not individual weigh-ins.¹

Some people notice appetite change and early loss in week one, while others feel little until a higher dose. Both are normal. Early loss includes water weight, which is why the trend over weeks matters more than any single weigh-in.

When your prescriber reviews progress

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. A pen that is cheap but unreviewed does not tell you whether the treatment is working for you. Our ongoing monthly reviews are included, so a decision to move up to 15mg, hold at a lower dose or stop is made with a clinician rather than in isolation.

08 · How Mounjaro works

How Mounjaro works and early side effects

Mounjaro works by activating two natural gut-hormone receptors at once: GIP and GLP-1. Tirzepatide is the first treatment of its kind to do this. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹

In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet. This dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide (Wegovy and Ozempic). The medicine does not replace diet and activity; it makes a reduced-calorie diet easier to follow.

Half-life and what it means at 15mg

Tirzepatide has a half-life of about five days. After a final dose it takes roughly 4 to 5 weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears. This matters at 15mg because the effects, including side effects, do not stop the day after an injection or even the week after.

Common early effects

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects, and they usually settle. Many people choose a weekend morning to inject so early side effects fall on days off. There is no 'best' time of day, since Mounjaro works the same morning or evening, with or without food. What matters is the same day each week.

The UK Mounjaro patient leaflet lists the side effects. Very common effects (may affect more than 1 in 10 people) include feeling sick, diarrhoea, being sick, stomach pain, constipation, feeling tired and reduced appetite. Common effects (up to 1 in 10) include dizziness, indigestion, bloating, burping, reflux, hair loss, injection-site reactions, gallstones and gallbladder inflammation.¹³

New symptoms and reporting

A symptom that is not on the leaflet list is not a listed side effect; tell your prescriber about any new or lasting symptom. Not every symptom someone experiences while on a medicine is caused by it, and a clinician can help separate the two. You can also report suspected side effects through the MHRA Yellow Card scheme.¹⁹ Our team provides side-effect support as part of ongoing monthly reviews.

Medicines and contraception

Because Mounjaro slows stomach emptying, it can reduce absorption of oral contraceptives. The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ If you take insulin or sulfonylureas, doses may need adjusting because of the risk of low blood sugar; this is something to plan with your clinician, not a reason to avoid the conversation. Tell your prescriber about every medicine you take, including those bought over the counter, so the consultation can check the combination is suitable.

09 · Managing cost over a year

Managing the cost of 15mg safely

• Use the discounts. New customers save £40 on their first order with code FIRST40, and an automatic £25 reorder discount applies to every future order (code DOSE25).
• Spread the payment. We accept Visa and Mastercard, Klarna and pay-monthly options, with no subscription lock-in.
• Compare on the same dose and date. Across the UK pharmacies we track, the gap for the same dose runs from £20 to £36.03.

Stopping at 15mg

You can stop Mounjaro at 15mg, but do so with your clinical team rather than on your own. After the final dose the medicine takes roughly 4 to 5 weeks to clear.

Ready to compare the pen price at other doses? See the Mounjaro pen price guide or the starting-dose price page.

10 · NHS and eligibility

NHS access versus private prescribing

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 think you may qualify on the NHS, ask your GP. Private treatment is a separate route, with its own consultation and its own cost.

Wegovy sits on a different footing: NHS access to Wegovy runs through specialist weight-management services, so ask your GP.

Licensed eligibility for private prescribing

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 include 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.¹¹¹

A prescriber will assess your BMI, medical history and current medicines before deciding whether it is suitable for you. Mounjaro is not suitable for everyone. You should not take it if you are allergic to tirzepatide or any of its ingredients, and it should not be used during pregnancy or while trying to conceive. Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems. Always share your full medical history and medicine list during consultation. Stop the medicine and tell your prescriber promptly if you become pregnant, and stop it at least one month before trying to conceive. Orders found unsuitable are refunded automatically in full.

Can people with diabetes get it on the NHS?

Mounjaro is also licensed for type 2 diabetes. Whether you can have it on the NHS for diabetes depends on your clinical situation and local prescribing decisions, so speak to your GP or diabetes team. Private weight-management prescribing requires its own consultation. If you already take diabetes medicines such as insulin or sulfonylureas, tell the prescriber, because doses may need adjusting.

Choosing a route

The honest picture is that the two routes can sit side by side. Some people join an NHS pathway when it opens to them and use private treatment meanwhile. Our weight loss treatments overview sets out the alternatives so you can choose with a clinician.

11 · Buying safely

Buying a 15mg pen safely: counterfeits and genuine checks

Buy a 15mg Mounjaro pen only from a pharmacy you can verify on the GPhC register. 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

Never buy from social media, beauty salons or unverified websites. Genuine treatment always involves a prescription and a clinical consultation, so a seller offering to supply without a consultation or prescription is a warning sign in itself. You can check our registration (GPhC 9012878) on the GPhC register.¹²

What a genuine pen looks like

A genuine UK Mounjaro pen comes from a registered pharmacy with a batch number and expiry date, arrives cold-chain packaged, and the solution inside is clear and colourless. Genuine UK stock is supplied through Eli Lilly's official distribution to licensed pharmacies, and our pens come through official LillyDirect supply.

Do not use a pen that has been frozen, looks cloudy or discoloured, has particles in it, is past its expiry, or has been above 30°C or out of the fridge for more than 30 days in use. If supply or packaging ever seems wrong, check the pharmacy on the GPhC register and contact the pharmacy before injecting.¹

Delivery and cold chain

Because the pen must be kept cold until first use, delivery matters. Our delivery is free, next-day and tracked, using DPD with discreet, temperature-controlled packaging. Orders placed by 3pm are dispatched the same day. When a parcel arrives, put the pen in the fridge at once, unless you are injecting that day, and keep it there until first use.

Warning signs when comparing prices

• A seller who does not ask health questions or does not mention a prescriber.
• No GPhC registration number, or one that does not match the pharmacy name on the register.
• Pens described as 'repackaged', 'split' or sold by the dose rather than the pen.
• Offers promising specific results, or dramatic weight-loss claims.

None of these apply to regulated pharmacies, which is why a price comparison should always start with who is dispensing, and only then with how much it costs. Our 15 mg pricing page lists the live figures by provider.

Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity, and individual results vary.

12 · Using your pen

Using a 15mg pen: injecting, missed doses and storage

Mounjaro is injected under the skin (subcutaneously) once a week, on the same day each week, at any time of day, with or without food. 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. Each KwikPen contains four weekly doses.¹¹³

Every order comes with needles, a sharps bin and injection guidance, and the patient information leaflet shows each step.

Missed doses and changing your day

If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day. If more than 4 days have passed, skip the missed dose entirely and take the next one on your normal day. Never take two doses within 3 days of each other.¹

You can change your weekly injection day if needed, as long as at least 3 days (72 hours) have passed since your last dose. This is useful if your routine changes or you are travelling. Our free GLPTrackr companion app (iOS and Android) can help you track injection days and your progress.

Storage

Keep Mounjaro pens in a fridge at 2 to 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 pen cap on to protect it from light, and never use a pen that has been frozen.¹

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 remembered day limit; figures circulating online often come from other countries' labels. The patient information leaflet and the pharmacy are the right places to ask.

Travelling with a 15mg pen

You can fly with Mounjaro. Carry 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. 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.¹

No food is banned on Mounjaro, including bananas. Many people feel worse after very fatty, fried or very sugary food, and smaller, slower meals work better. If a particular food or drink makes your nausea worse, mention it at your monthly review so your prescriber can advise.

13 · 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 A fast heartbeat can also be a sign of a severe allergic reaction; get medical help straight away.