Mounjaro KwikPen 2.5mg/0.6ml Solution for Injection, 2.4ml Pre-filled Pens (October 2026)

01 · Cost

What the 2.5mg KwikPen costs and what you get

The standard price of one 2.5mg pen is £169.99, and one pen is one month of treatment at the starting dose. That is four weekly injections from a single pre-filled pen. As a new customer, your first order is £40 less with code FIRST40, so your first 2.5mg pen costs £129.99. After that, every later order is £25 off the standard price (code DOSE25). You can see current doses and prices on the Mounjaro pen product page, and all six doses are in stock.

The consultation is free, and the price shown is the price paid, with no hidden fees. Needles, a sharps bin and injection guidance are included with every order. Delivery is free, next-day and tracked, in temperature-controlled packaging, and same-day dispatch applies when you order by 3pm. Saturday delivery is £14.99. We supply Mounjaro through official LillyDirect supply, direct from Eli Lilly's UK distribution, so the pens are genuine KwikPens.

For a fuller breakdown of this one strength, see our guide to Mounjaro 2.5mg injection pricing.

02 · Planning

Planning beyond the first pen

The 2.5mg pen is only the first step, so it helps to see the cost of the whole journey. These are standard prices before any discount. A new customer's first order is £40 less, and every later order is £25 less.

If you settle somewhere in between, the monthly price is what counts: £279.99 at 7.5mg, £290.99 at 10mg and £319.99 at 12.5mg. Your prescriber guides which dose is right, and a higher dose is not automatically better. Across the UK pharmacies we track, a starting 2.5mg pen runs from £143.96 to £179.99 (index checked 12 October 2026), so it is worth comparing like with like. You can also browse all weight loss treatments if you are still deciding.

03 · NHS or private

NHS or private supply

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. Ask your GP where you sit in the local pathway; if private treatment suits you better, it is the same licensed medicine.

04 · Ordering

How ordering works

Ordering takes three steps and starts with a free, no-obligation consultation.

• 1. Free online consultation. Complete a short health questionnaire through our free weight loss consultation.
• 2. Prescriber review. A GPhC-registered prescriber reviews your answers. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• 3. Dispensing and delivery. Our registered pharmacy dispenses your pen and sends it by free next-day tracked delivery.

Payment is by Visa or Mastercard, Klarna or pay-monthly options, with no subscription lock-in. Repeat orders re-check your suitability, and nothing ships automatically. Ongoing monthly reviews with the prescribing team are included.

05 · Reading the pen label

What the pen name and label tell you

The full product name, Mounjaro KwikPen 2.5mg/0.6ml solution for injection in a 2.4ml pre-filled pen, packs several facts into one line. 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.¹ It comes as a pre-filled multi-dose pen, called a KwikPen, in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹

The 2.5mg figure is the dose delivered in each weekly injection. The 0.6ml figure is the volume the product name gives for that dose, and the 2.4ml figure is the total volume in the pen. Each KwikPen contains four weekly doses, which is why one pen lasts four weeks when you inject once a week.¹³ You do not measure anything yourself.

You may see a similar-looking name for the next strength up, such as tirzepatide 5mg/0.6ml in a 2.4ml pre-filled disposable device. Each strength is its own pen with its own label, so the number on the box tells you which dose you are holding. Always check the strength printed on the carton and on your pharmacy label against what your prescriber told you before you inject. If anything looks different from what you expected, contact the pharmacy before using the pen.

The pen is a disposable device. When the four doses are used it is finished, and used pens and needles go into a sharps container rather than the household bin. You can add a 1 litre sharps container to an order, and a sharps bin is included with every order anyway.

Because the product is a prescription-only medicine, it can be supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary, and this page is information, not a substitute for medical advice. You can check our registration on the GPhC register (9012878), and the pre-filled 2.5mg pen guide covers the same product from a slightly different angle.

One practical point is what the 2.5mg pen is for. Everyone starts Mounjaro on 2.5mg once a week, and this starting dose is about letting your body adjust, not about weight loss itself.¹ Think of the first pen as an introduction to the medicine, the routine and the pen itself, before the dose rises.

06 · How tirzepatide works

How Mounjaro works and how it differs from semaglutide

Tirzepatide activates two natural gut-hormone receptors at once, GIP and GLP-1, and it is the first treatment of its kind to do so. 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. The medicine is a support for diet and activity changes, not a replacement for them.

That dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide, sold as Wegovy and Ozempic.¹ People often ask which is better. Both are licensed, effective treatments, and the honest answer is that it depends on the person. One trial, SURMOUNT-5, compared tirzepatide with semaglutide directly in adults with obesity.¹⁵ Trial averages do not predict your own result, and tolerability, medical history and preference all matter.

The practical differences are easy to state. Mounjaro is a once-weekly injection with six strengths from 2.5mg to 15mg. Wegovy is also once weekly, with a ladder of 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg, stepping up after at least four weeks and reaching the 2.4mg maintenance dose from week 17. Liraglutide products such as Saxenda are a daily injection, which is a different routine altogether. If you want to see the other options in one place, our weight loss treatments overview sets them side by side.

How long the medicine stays in the body matters for planning. 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.¹ There is no way to speed this up, and nothing needs doing while it clears.

The slowing of stomach emptying has one specific practical consequence. Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed.⁷ 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 Tell the prescriber about every medicine you take, including insulin or sulfonylureas, because doses of those may need adjusting to avoid low blood sugar.

None of this makes the 2.5mg pen a strong-acting dose. Its job is to introduce the medicine gently while your body adjusts. The mechanism builds from there as the dose is stepped up under prescriber guidance.

07 · Injecting the KwikPen

How to inject the tirzepatide KwikPen

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.¹ 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.¹

The step-by-step handling is set out in the patient information leaflet that comes in every box, and you should follow the pen's instructions exactly. In outline: wash your hands, check the pen label and strength, attach a new needle, set the dose, choose and clean your site, inject, then dispose of the needle safely in a sharps container. Needles and injection guidance are included with every order.

Setting the dose

You set the dose by turning the dose knob until the dose indicator shows the correct dose in the window.

What if I forgot to prime?

Priming steps differ between pen designs. If you think you missed part of the preparation, do not guess or inject a second dose to compensate. Read the patient information leaflet and contact the pharmacy or your prescriber, who can tell you whether the pen is still safe to use. Our support team is available Monday to Friday, 9am to 5pm, on 0333 207 0413 or at support@everydaymeds.co.uk.

Best time of day

There is no best time of day. Mounjaro works the same morning or evening, with or without food. What matters is the same day each week. Pick a day and time you will remember. Many people choose a weekend morning so early side effects fall on days off.¹

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.¹

For more on this exact strength, see our 2.5mg/0.6ml guide.

08 · Storage and travel

Storing the pen and travelling with it

Keep Mounjaro pens in a fridge at 2 to 8°C and never freeze them.¹ Once a pen is in use, it 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.¹ Keep the cap on to protect the pen from light, and never use a pen that has been frozen.

For a 2.5mg pen that holds four weekly doses, the in-use window of up to 30 days not above 30°C covers the four weeks of treatment. The sensible habit is simple: return the pen to the fridge after each injection unless you are away, and keep unused pens in the fridge until you need them. Unopened pens should be kept in the fridge and keep until the expiry date printed on the box.¹

What if an unopened pen was left out?

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 the UK product information is what applies to your pen. Describe how long it was out and roughly how warm it was, and the pharmacy can advise. Pens that have frozen should not be used.

Flying and holidays

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.¹ 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.

Pack needles and a small travel sharps solution as well as the pens. If you are away for longer than a single in-use pen lasts, discuss timing with the pharmacy before you go, so that your next pen can be organised in advance.

When your parcel arrives

Orders travel by free next-day tracked delivery in temperature-controlled packaging, designed to be discreet. Open the parcel promptly and put the pens into the fridge. If anything looks damaged or wrong, contact us within 3 days, because dispensed prescription medicines can be returned only if faulty, damaged or the wrong item. Refunds in those cases take 5 to 10 working days.

Anyone sharing a household should know where pens are kept, and pens should be kept out of children's sight and reach. Disposal is simple: needles and finished pens go in a sharps container, never loose in a bin. See also our guide to the 2.4ml pen format.

09 · After the 2.5mg pen

What comes after the 2.5mg pen

After at least 4 weeks on 2.5mg the dose increases to 5mg, and can then step up by 2.5mg at a minimum of 4-week intervals, to 7.5mg, 10mg and 12.5mg, up 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 guides the right pace.

This is why the first pen matters less for its strength than for its role. A starter pen gives four weeks of gentle exposure so that nausea, tiredness and appetite changes can be judged before moving on.

Can I stay on 2.5mg for longer?

That is a clinical decision made with you, not something to do on your own. Ongoing monthly reviews, dose-titration and follow-up assessments by our prescribing team are part of the service.

Ordering the next pen

Repeat orders re-check your suitability, and nothing is shipped automatically. Every later order is £25 off the standard price. For the next strength, the standard monthly prices are £218.99 at 5mg and £279.99 at 7.5mg, and the Mounjaro pen page shows every dose. If you are switching from another provider at a higher dose, your first order with us is still £40 less with code FIRST40; at 15mg that first order is £289.99.

If you are building a plan for more than one pen at a time, our page on ordering two pens explains the practicalities. Whatever you choose, the prescriber decides the dose you receive, not the order form.

Treatment response is also reviewed. 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

10 · Results and early weeks

What to expect from the first weeks and beyond

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.¹ Experiences differ widely: some people notice appetite change and early loss in week one, others feel little until a higher dose, and both are normal. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in.

People ask how long Mounjaro takes to kick in. Appetite changes can appear after the first injection for some, while for others they come with later doses. Trials measured results at 72 weeks, so think in months, not days, and judge progress by trend rather than individual weigh-ins.

Common early effects

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹ Choosing a weekend morning for your injection means these fall on days off. Report anything that worries you to your prescriber, and you can report suspected side effects through the MHRA Yellow Card scheme.¹⁹

Trial results, with context

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, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² These are trial averages and individual results vary. Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them. For someone starting at 100 kg, 20.9% is about 21 kg.

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 None of those figures relate to the 2.5mg starting dose, which is not the dose those results describe. Treat the starter pen as the doorway rather than the destination.

If you want a closer look at the first stage specifically, see our article on weight loss on the 2.5mg KwikPen. Trial averages do not predict your own result, so use them as context rather than a promise.

The GLPTrackr companion app is a free way to track your journey, including injection days, doses and weight trend, on iOS and Android.

11 · Who can use it

Who can and cannot take Mounjaro

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 must be used alongside a reduced-calorie diet and increased physical activity. A prescriber assesses your BMI, medical history and current medicines before deciding whether it is suitable for you.

People often ask who should not take Mounjaro. 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.¹³ Always share your full medical history and medicine list during consultation. Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. If you become pregnant during treatment, stop the medicine and tell your prescriber promptly. If the prescriber decides it is not suitable, an unsuitable order is refunded automatically and in full.

Medicines and contraception

Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed. Switch to a non-oral method, or add a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase. This applies to the pill only.⁷ If you use insulin or sulfonylureas, doses may need adjusting because of the risk of low blood sugar. That is a conversation for your prescriber, not a reason you cannot be treated.

Food and alcohol

No food is banned on Mounjaro, including bananas. Prioritise protein at each meal, vegetables and fibre, and regular fluids. Many people feel worse after very fatty, fried or very sugary food, and large portions sit heavily because the stomach empties more slowly, so smaller, slower meals work better. There is no direct interaction between Mounjaro and alcohol, but drinking on a reduced appetite and emptier stomach can hit harder than usual. If you also take insulin or a sulfonylurea, alcohol increases the risk of low blood sugar. Treatment is used alongside a reduced-calorie diet and increased physical activity, so a balanced approach to eating is part of the plan.

New symptoms

If a new symptom appears that you are unsure about, speak to your prescriber, and report suspected side effects through the Yellow Card scheme.¹⁹ Do not rely on forums or marketplace sellers for advice on this prescription medicine.

Avoiding counterfeits

Counterfeit weight-loss injections have been the subject of MHRA alerts.⁷ Be wary of anyone offering to supply without a consultation or prescription, or selling pens through social media or marketplaces. A genuine supplier is a registered pharmacy that you can check on the GPhC register. Ours is registration 9012878, and our Mounjaro comes through official LillyDirect supply from Eli Lilly's UK distribution. Related reading: the KwikPen 2.5mg product guide.

Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. Individual results vary. This page is information, not a substitute for medical advice.

12 · 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