Mounjaro Doses Explained: A Conversion Chart and What Each Step Means

What the licensed dose schedule actually says

The Mounjaro Summary of Product Characteristics, published on the electronic Medicines Compendium, sets out the schedule clearly: start at 2.5mg weekly for four weeks, then increase to 5mg weekly for four weeks. After that, the prescriber may continue to raise the dose in 2.5mg steps at minimum four-weekly intervals, based on how you are tolerating treatment and how your body is responding. The ceiling is 15mg weekly.

That produces a simple conversion chart: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg, six steps, each 2.5mg above the last. What the chart cannot show you is when to move. That timing is a clinical decision, not an arithmetic one. Tolerability at the current dose, any side effects, weight trajectory and your medical history all feed into it. Prescribers at nume review this evidence before every repeat, a real clinician reads your notes, not software.

You can find the Mounjaro SmPC on the eMC, which carries the exact wording on dosing, storage and contraindications. For a practical breakdown of how dose volumes translate to pen clicks, the Mounjaro dose-to-clicks guide covers the mechanics of the KwikPen in plain terms.

Trial evidence: what weight loss looks like across the dose range

The clearest picture of how dose relates to outcome comes from SURMOUNT-1, a 72-week randomised trial of tirzepatide in adults with obesity published in the New England Journal of Medicine. Participants on 5mg lost an average of around 16% of body weight; those on 10mg lost roughly 21%; and those on 15mg reached around 22.5% on average. The 2.5mg arm was not included as a maintenance arm in that analysis, reinforcing why the starting dose is understood as an adjustment phase rather than a therapeutic target.

These figures come from a trial population of 2,539 adults. That is the correct scale for SURMOUNT-1 specifically; the broader tirzepatide clinical programme across SURMOUNT and SURPASS studies involved more than 10,000 participants combined. The headline trial results are also what NICE based its recommendation on when it published Technology Appraisal TA1026 in December 2024, recommending tirzepatide for adults meeting specific BMI and comorbidity thresholds.

A clean comparison of the six strengths and their associated trial outcomes is set out in the Mounjaro dosage chart, which draws on the same published evidence. For the evidence on the highest maintenance dose specifically, the golden dose breakdown goes into more detail on what 15mg data show.

Why the chart has six steps and not fewer

Tirzepatide is a dual GIP and GLP-1 receptor agonist, it acts on two gut-hormone pathways simultaneously, which is why its side-effect profile and its weight-loss potential both differ from single-pathway medicines. Gastrointestinal effects (nausea, loose stools, indigestion) are most common early in treatment and after each dose increase, then typically settle over days to a couple of weeks. The gradual titration schedule exists precisely to let your digestive system adapt before the dose rises again.

This is why a provider skipping someone straight to 10mg or 15mg (without evidence of tolerance at the preceding steps) is not following the licensed schedule. The 5mg dose page covers what to expect at that first therapeutic step in more detail, including the side-effect pattern that the prescriber watches for before recommending a move upward.

For context on how the private cost of treatment shifts as the dose increases, the Mounjaro cost guide explains honestly what drives UK pricing, including the significant Lilly list-price change that came into effect in September 2025. One transparent price that covers consultation, prescription and free next-working-day delivery is worth checking before you compare figures from different providers.

What a dose conversion chart cannot tell you

A tirzepatide dose conversion chart tells you the steps. It does not tell you which step you belong on, how fast you should move, or whether you should stay at an intermediate dose rather than pushing to the maximum. Those answers sit in your clinical record, your weight response over time, any side effects you have reported, your other medicines, and your prescriber's judgement.

Under the NICE TA1026 recommendations, continuing Mounjaro beyond six months requires evidence of at least 5% weight loss at the highest tolerated dose. That is a clinical review criterion, and it illustrates why dose management is a continuous conversation rather than a one-off chart lookup. Our prescribers carry out that review before each repeat, ask a question before your Sunday evening injection and you will typically have a response the same day. If you want to understand the full Mounjaro treatment picture before deciding anything, that overview is a sensible starting point.

Tirzepatide is a Prescription-Only Medicine. Whether the dose on the chart is the right one for you is something a prescriber determines after a proper clinical assessment, not something any chart, calculator or webpage can decide for you.