The Mounjaro patient information leaflet: what the official document tells you

What MHRA approval of the leaflet actually guarantees

Every patient information leaflet included with Mounjaro has been reviewed and authorised by the MHRA as part of the UK marketing authorisation for tirzepatide. That means the language, the warnings and the instructions are legally required to reflect the best available evidence at the time of approval. The clinical information about Mounjaro you find in the leaflet is the same information your prescriber works from, the Summary of Product Characteristics (SmPC) on which the leaflet is based is published on the Electronic Medicines Compendium. If you ever want to cross-reference the full technical document, the eMC listing for tirzepatide is the right place to look.

The NICE appraisal of tirzepatide (TA1026, published December 2024) drew directly on the data underpinning the SmPC, including the SURMOUNT-1 trial results showing an average body-weight reduction of around 20–21% over 72 weeks at the 15 mg dose, figures quoted in the evidence review and consistent with the contraindication and monitoring guidance the leaflet carries. Understanding that the leaflet is downstream of that evidence base helps you trust its instructions rather than second-guess them.

One thing worth knowing: the leaflet inside your box reflects the version current at the time of manufacture. Eli Lilly occasionally updates the document as new safety data emerge. The most current version is always available on the eMC, and the tirzepatide patient information PDF linked from that resource is the authoritative digital copy.

The sections of the Mounjaro leaflet that patients most often overlook

Most people read section 4 (possible side effects) carefully, which makes sense. The gastrointestinal effects (nausea, loose stools, indigestion, constipation) are the ones most commonly noticed in the early weeks and are described clearly, including the reassurance that they typically settle as the body adjusts. What patients sometimes skip is section 2, which lists the medicines and conditions that require extra care or mean Mounjaro shouldn't be used at all. If you take oral contraceptives, for example, the leaflet explains that tirzepatide slows gastric emptying in a way that can reduce absorption of the pill; adding a non-oral method of contraception for the first four weeks of treatment and for four weeks after each dose increase is the recommended precaution, consistent with NHS guidance.

Section 3 covers how and when to inject, which sites to use (abdomen, thigh or upper arm), and how to rotate them. It also covers storage: refrigerated at 2–8°C, with a limited room-temperature window whose exact length is specified there, not something to guess at from memory. The Mounjaro leaflet guide on this site summarises those practical instructions, but the printed document in your box is always the primary reference.

Section 5 covers what to do with unused medicine and the pen after use. Sharp waste from injection devices should be disposed of in an approved sharps container, your pharmacist or prescriber can advise on local disposal routes.

Side effects listed in the leaflet that need urgent medical attention

The tirzepatide patient information leaflet is unambiguous about which symptoms shouldn't wait for your next scheduled review. Severe and persistent stomach pain that radiates toward the back (with or without vomiting) is the described presentation of acute pancreatitis; the leaflet instructs patients to stop treatment and seek medical help immediately. In January 2026 the MHRA issued a Drug Safety Update reinforcing this message across all GLP-1 medicines, citing pancreatitis as a known but infrequent risk that requires prompt assessment, as documented in the MHRA's Drug Safety Update index.

Other urgent signs in the leaflet include symptoms of a serious allergic reaction (swelling of the face or throat, difficulty breathing), gallbladder problems (pain in the upper right abdomen, fever, jaundice), and signs of severe dehydration if persistent vomiting or diarrhoea prevents adequate fluid intake. The full tirzepatide overview on this site covers these in plain language, but the leaflet itself should be kept somewhere accessible (not at the back of a drawer) so you can check it quickly if a symptom concerns you.

For non-urgent queries, our frequently asked questions page covers the questions our prescribers hear most often week to week. If something feels off and you're unsure whether it's urgent, call 111 or speak to a pharmacist. You can also report suspected side effects directly to the MHRA at yellowcard.mhra.gov.uk.

The patient information leaflet doesn't tell you what dose to take, here's why that matters

This is possibly the most important thing to understand about the document. The leaflet describes the licensed dosing schedule (starting at 2.5 mg for tolerability, progressing through the available strengths) but it does not tell you, specifically, when to move up, whether to stay at your current dose, or what to do if you missed an injection. Those decisions belong to your prescriber, who has your full clinical picture. The leaflet describes the framework; the prescriber applies it to you.

If you are considering starting tirzepatide privately and want to understand how Mounjaro pricing works across providers, that context is worth reading before you begin. The cost of a legitimate private prescription should always include clinical assessment, not just the pen.

If you'd like to explore whether you meet the eligibility criteria for treatment, our clinical team (whose background you can read about on the clinical team page) reviews every consultation personally. The Mounjaro patient leaflet resource on this site is a helpful companion, but formal treatment questions are answered through the consultation process. You can also browse the broader weight-loss treatment options available if you're still at the research stage.

We know that sitting with a new medicine, a new pen device and a leaflet dense with warnings can feel overwhelming, particularly if you've waited a long time to reach this point. Reading the document once, carefully, is time well spent. After that, the questions that remain are the ones a prescriber is there to answer. Check your eligibility with our team whenever you're ready.