What counts as a full dose of Mounjaro — and how the licensed schedule works

Where the dosing schedule comes from

The Mounjaro dosing schedule is set out in the medicine's Summary of Product Characteristics, authorised by the MHRA. It was shaped by the SURMOUNT programme of clinical trials, which studied thousands of adults over 72-week periods to establish both the safety profile at each strength and the level of weight reduction achievable. The NHS medicines page for tirzepatide summarises the licensed schedule clearly for patients.

Treatment starts at 2.5mg for the first four weeks. That starter pen's job is adjustment, many people experience nausea, indigestion or loose stools when GLP-1 medicines begin, and the 2.5mg strength keeps those effects manageable while your digestive system adapts. From there, the prescriber typically steps the dose up by 2.5mg every four weeks, moving through 5mg, 7.5mg, 10mg and 12.5mg before reaching the ceiling of 15mg.

Each of those strengths is a full, complete dose at that stage. There is no sense in which 5mg is a "half dose" of 10mg, it is the prescribed dose for weeks five to eight of the standard schedule. The pen is designed so that one injection delivers the entire contents; a full dose, in practical terms, is simply the complete injection from your current pen.

For a closer look at how the very first strength fits into this picture, our guide to the Mounjaro starting dose covers what to expect in those opening weeks.

What the trial data shows about higher doses

The SURMOUNT-1 trial, published in the New England Journal of Medicine, followed 2,539 adults over 72 weeks. At the 15mg maintenance dose, participants achieved an average body-weight reduction of around 20–21%. Lower maintenance doses produced meaningful results too, the trial tested 5mg, 10mg and 15mg as maintenance targets, and all three arms outperformed placebo significantly. This matters because not everyone reaches 15mg, and those who stay at a lower strength because of tolerability still have clinical evidence behind their treatment.

The concept of a "golden dose" (a particular strength at which results plateau and side effects settle) is something people search for understandably. Our page on whether the golden dose is a full dose unpacks that idea in detail. The short answer is that the right dose is an individual clinical question, not a universal sweet spot that applies to everyone.

NICE, in its appraisal of tirzepatide (TA1026), noted that patients who have not lost at least 5% of their body weight after six months at the highest tolerated dose should have their treatment reviewed. That framing is instructive: "highest tolerated dose" acknowledges that some people's ceiling is 10mg or 12.5mg, and that is still a legitimate, full treatment course.

How to tell whether you received the complete injection

This is one of the questions our prescribers hear regularly. Each Mounjaro KwikPen contains four weekly doses at the labelled strength. When you inject, the pen delivers one pre-set amount, you do not control how much comes out. After the injection, the plunger should have advanced and the dose counter should confirm the injection is complete.

If you are unsure whether the full contents were delivered (perhaps the pen felt different, or the injection site bled more than usual) our guide to what to do if you think you missed your full dose covers the practical steps. And if you want to understand the mechanical side more precisely, this page on how many clicks a full dose involves explains what to listen and feel for during the injection.

One thing worth knowing: the pen is not a syringe you partly depress. It is designed to release a fixed, complete dose in a single use. If the injection felt smooth and complete, it almost certainly was.

Missed doses and what to do when life gets in the way

Weekly injections fit most routines well, but life intervenes, a bank holiday moves your usual day, or you notice on a Friday afternoon that you forgot Monday's pen. A consistent injection day each week is the aim. If you miss one, our missed-dose guide gives the specific guidance on timing and when simply to wait for your next scheduled injection instead.

The Patient Information Leaflet inside your pen box is the authoritative source for missed-dose instructions, and your prescriber is always the right person to call for anything outside that standard scenario, a holiday stretching the gap, or a period of illness affecting your injections.

If you are weighing up whether to explore Mounjaro or want to understand more about how treatment is structured before committing, checking your eligibility through a free consultation is the natural next step. Our prescribers review every consultation the same day, a real clinician reads your answers, not an automated system. For broader context on how Mounjaro fits into the UK weight-loss treatment landscape, our main Mounjaro page covers the full picture, and our treatment overview sets out all the options available through nume.