Mounjaro Package Insert (UK): Where to Find It and What It Says

01 · The core answer

What is the UK package insert for Mounjaro?

The UK package insert is the Patient Information Leaflet, a folded sheet inside the carton written in plain language for the person using the pen.¹³ The Summary of Product Characteristics (SmPC) is the technical document written for healthcare professionals, and it underpins everything in the leaflet.¹

Tirzepatide is the active ingredient and Mounjaro is the brand name, so one set of UK documents covers both.

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 (KwikPen) in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹

02 · Your next step

Do you need the leaflet, or advice for your own situation?

If you already have a pen, read the leaflet that came with it and keep it to hand. It is the document your pharmacist and prescriber expect you to have read.

If you are still deciding whether the medicine is right for you, a leaflet cannot assess your health. A consultation reviewed by a GPhC-registered prescriber can. Our weight loss clinic explains how that works, and you can see current options on the Mounjaro pen page.

If you want practical help with the injection itself, our guides to where to inject Mounjaro and the pen needle question go further than a leaflet can.

Related guide: Where to insert mounjaro shot.

03 · UK versus US documents

Why the UK leaflet differs from the US label

The UK documents differ from the American "prescribing information" in licensing, wording and practical instructions. The American document was written for a different regulator and a different market.

Storage windows, brand names and some sections of advice are not interchangeable between the two. If a US document gives a storage period or a licensed use that differs from your leaflet, follow the UK document and ask your pharmacist.

The UK documents are the ones that apply to a pen supplied by a UK pharmacy, so use them rather than a figure you saw in an American PDF.

04 · How to find the PDFs

How to find the Mounjaro package insert PDF

The simplest route is the electronic medicines compendium (emc), which hosts the current UK SmPC and Patient Information Leaflet for Mounjaro KwikPen.¹¹³ Both are free, and you can read them on screen or save them as a PDF.

• Choose the Patient Information Leaflet if you are a patient, and the SmPC if you want the full professional detail.
• Check the revision information on the document so you know it is current.
• Keep the carton leaflet too, because it matches the pen you were actually supplied.

The leaflet is updated from time to time, so a PDF you saved a while ago may be out of date. Download a fresh copy when you start a new treatment course or when your prescriber mentions a change.

05 · What the leaflet covers

What the Mounjaro leaflet covers, section by section

The leaflet follows a standard layout used across UK medicines, so once you know it you can read any of them.

What it is and what it is used for. This explains the licensed uses. Mounjaro works by activating 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

Before you use it. This lists who should not use the medicine, warnings and precautions, and interactions with other medicines. 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. It also covers pregnancy, breastfeeding and driving. 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. Read it carefully, and tell your prescriber about every medicine you take, including those bought without a prescription.

How to use it. This gives the dosing schedule, how the dose steps up, and what to do about a missed dose. Your prescriber sets your personal plan, and the leaflet is the reference point if you are unsure.

Possible side effects. This lists side effects grouped by how common they are, along with the symptoms that need urgent medical attention. It also explains how to report problems through the Yellow Card scheme.¹⁹

How to store it. This covers fridge storage, how long a pen in use can stay out, and disposal of used pens. The final part gives the ingredients and the marketing authorisation holder.

A separate set of instructions for use, with diagrams of the pen, usually sits alongside the leaflet. It shows each part of the KwikPen and the order of steps for an injection.

06 · Storage and in-use pens

Storage instructions in the UK documents

Store unopened pens in the fridge until first use, and they keep until the printed expiry date.¹³ Fridge storage means a temperature of 2–8°C.¹

Once you start using a KwikPen, UK documents allow it to be kept out of the fridge for up to 30 days (not above 30°C).¹ Do not use a different figure from a non-UK source. Do not use a pen that has been above 30°C or has been frozen. Check the leaflet and ask the pharmacy that supplied it.

For an unopened pen that has been out of the fridge, check with your pharmacy and the leaflet before using it. Treat any pen you are unsure about as unusable until you have checked, because sterility and potency are no longer assured outside the tested window.

07 · Using the leaflet safely

How to use the leaflet alongside your prescriber

The leaflet is written for everyone who might take the medicine, so it cannot tell you what is right for you personally. Use it to understand the medicine, then use your prescriber to apply it to your health, your other medicines and your goals.

Tirzepatide 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. Individual results vary.

Read the leaflet's list of warnings before your first dose, not after. If something in it applies to you, such as another medicine you take or a health condition, raise it with your prescriber first. Contraception is one example: Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed. 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 notice a new symptom, speak to your prescriber. You can also report a suspected side effect directly through the Yellow Card scheme, which the leaflet explains how to do.¹⁹

08 · What the leaflet does not say

What a package insert does not tell you

A leaflet describes the medicine, not your outcome. It will not predict how much weight you lose, and it is not a prescribing guide for your personal dose plan.

Trial results come from published studies rather than the leaflet. 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. These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

Nor does a leaflet explain how to get the medicine on the NHS. 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, and the NHS primary-care rollout began in June 2025 with the highest-need groups first (initially BMI 40+ with four or more qualifying conditions). Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.⁴⁵

09 · The injection and your pen

Injection guidance beyond the leaflet

The leaflet and the instructions for use describe the injection steps, and you should follow them exactly as written for your pen. Always follow the pen's instructions for how to deliver the dose, rather than relying on advice from forums or videos.

Many people also want practical detail on where on the body to inject and which needles to use. Our guides to the best place for Mounjaro injections and the Mounjaro package contents cover those questions in plain language. Needles, a sharps bin and injection guidance are included with every order we dispatch.

Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4–5 weeks to clear the system — there is no way to speed this up, and nothing needs doing while it clears.¹ If you are thinking about stopping, speak to your prescriber first. Stopping should always be planned with your prescriber, with diet and activity habits ready to carry the load. In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued treatment lost a further 5.5% on average.

10 · 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