What the Mounjaro website and official UK sources tell you

What Eli Lilly's UK-facing information confirms, and what it leaves to your prescriber

Eli Lilly publishes product information for Mounjaro through the standard UK regulatory route: the Summary of Product Characteristics and Patient Information Leaflet are held on the Electronic Medicines Compendium (eMC), the authoritative repository for licensed UK medicines. The manufacturer's own UK-facing pages reinforce the same message the regulator requires: Mounjaro is a prescription medicine for weight management, not an over-the-counter option, not a supplement, and not something a website can simply sell you. A prescriber assesses clinical suitability before any supply is made.

The SmPC sets out the six UK pen strengths (2.5, 5, 7.5, 10, 12.5 and 15 mg) and confirms that 2.5 mg is the starting point specifically to let the body adjust, with titration managed by the prescriber over subsequent months. Storage is refrigerated (2–8°C). If you want to understand exactly where and how to administer the medicine, our guide to mounjaro jab sites covers the abdomen, thigh and upper arm in detail, including how to rotate them each week. None of that is flexible guidance; it is the licensed protocol. One misconception our prescribers hear regularly is that a higher starting dose will produce faster results. The data don't support it, and the titration schedule exists to keep side effects manageable.

The eMC SmPC is worth bookmarking if you want the granular detail (contraindications, excipients, pharmacokinetics) without needing to interpret clinical trial papers. For everyday questions about administration and storage, the Patient Information Leaflet included in the box covers the same ground in plain language.

What NICE's appraisal of tirzepatide established for UK clinical practice

NICE TA1026, published in December 2024 and updated in September 2025, is the document that formally brought Mounjaro into NHS and private prescribing conversations in the UK. The committee reviewed the SURMOUNT clinical programme, which randomised thousands of adults across multiple trials, and concluded tirzepatide was clinically and cost-effective at the recommended thresholds.

The headline trial result from SURMOUNT-1 (72 weeks, published in the New England Journal of Medicine) was an average body-weight reduction of around 20–21% at the 15 mg dose. NICE's review also considered the SURMOUNT-5 head-to-head trial, published in the NEJM in 2025, which found tirzepatide produced greater average weight loss than semaglutide 2.4 mg over 72 weeks in adults with obesity and no diabetes. These are not figures from a single small study; they are the results that underpinned a formal UK regulatory recommendation.

The NICE recommendation applies to adults with a BMI of 35 or above plus at least one qualifying weight-related condition (such as high blood pressure, type 2 diabetes, obstructive sleep apnoea or dyslipidaemia). Lower thresholds apply for people from South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, reflecting UK guidance on ethnic-background BMI adjustments. Tirzepatide is also licensed for type 2 diabetes independently of the weight-management indication.

How private access through a regulated UK pharmacy differs from the NHS route

The NHS England guidance on weight-management injections sets out a phased NHS rollout tied to specific BMI and comorbidity thresholds. From June 2025 the first cohort became eligible: adults with a BMI of 40 or above plus four or more qualifying conditions. The second cohort (BMI 35–39.9 plus four or more conditions) became eligible in June 2026. Each phase opens to a narrower group than the full licensed population, and NHS access requires referral into a service offering wraparound dietary and activity support.

For people who meet the licensed criteria but fall outside the current NHS thresholds (or who prefer not to join a waiting list) a private prescription route through a GPhC-registered pharmacy is the lawful alternative. You can verify any online pharmacy against the GPhC register before you use it; the registration number is publicly searchable and takes seconds to check. If you want to understand how private costs compare across providers, our Mounjaro comparison page walks through what different price points typically include and exclude.

At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber (a real clinician reads your answers) and treatment is dispatched the same working day if clinically approved, arriving free the next working day by tracked DPD. No subscription, no auto-renewal; every repeat order is clinically re-reviewed. Learn more about tirzepatide as a treatment or explore weight-loss treatment options more broadly if you're weighing up the full picture before deciding.

Side effects: what the licensed sources say, and when to get help

The NHS and the Mounjaro SmPC align on the most common side effects: nausea, vomiting, diarrhoea, constipation, indigestion, burping, fatigue and headache. These are typically GI-led, most noticeable after a new dose or a dose increase, and often settle within a week or two as the body adjusts. Injection-site reactions are also reported. None of this should be surprising, slowing gastric emptying is part of how the medicine works, and a slower gut takes some getting used to.

Rarer but serious effects the official sources flag include acute pancreatitis. In January 2026 the MHRA issued a Drug Safety Update for GLP-1 medicines noting pancreatitis as an infrequent but potentially serious risk, seek urgent medical help for severe, persistent stomach pain that radiates toward the back, with or without vomiting. Gallbladder problems and signs of a serious allergic reaction are also listed as reasons to contact a doctor promptly.

The NHS tirzepatide medicines page gives a plain-English breakdown of side effects and the circumstances that need prompt attention, and our guide to the Mounjaro site covers administration detail that is worth reading alongside the leaflet inside the box. If you have questions that arise during treatment, our support team is available seven days a week, and your prescriber can be reached through aftercare. Suspected side effects can be reported directly to the MHRA at yellowcard.mhra.gov.uk.