Mounjaro conversion chart: reading the dose ladder and what it means for you

What does a Mounjaro conversion chart actually show?

The phrase "conversion chart" means different things depending on who is searching. For most people, it refers to a table that lines up each Mounjaro dose with the point in treatment at which it typically appears, and you can see exactly that kind of breakdown on our Mounjaro chart, which maps each pen strength to the week range in which it typically appears. There is no currency-style conversion calculation involved: the dose printed on your KwikPen is the dose delivered, in milligrams, with no adjustment for body weight in the standard licensed schedule.

A smaller group searching the same term are switching from another tirzepatide product, such as a compounded formulation, and want to know how vials or units in a syringe correspond to named Mounjaro pen strengths. That is a meaningfully different question, and the honest answer is that any such translation must be made by a prescriber who can see the concentration of the original product and your clinical history. A chart alone is not safe for that purpose.

The tirzepatide dose chart sits alongside this as a useful reference for understanding how the molecule's schedule compares across branded and compounded contexts, and the tirzepatide dosing conversion guide goes deeper on unit-level calculations for people switching from non-standard formulations.

Why does the titration schedule move in fixed 2.5 mg steps?

The 2.5 mg increment is not arbitrary. Tirzepatide activates both GIP and GLP-1 receptors, which slows gastric emptying and significantly reduces appetite. Those effects are real from the first pen, but gastrointestinal side effects, chiefly nausea, loose stools and occasional vomiting, are most likely to appear when the dose is new to your system. Starting at 2.5 mg means your gut has four weeks to adapt before the next step. It is an adjustment period, not yet the therapeutic range at which most weight loss occurs. The NHS patient information on tirzepatide confirms this titration rationale clearly.

Each subsequent 2.5 mg increase carries the same logic: a higher dose brings more appetite suppression and, potentially, more GI sensitivity in the early days after the change. Spacing increases four weeks apart gives the body time to settle, gives your prescriber time to review how you are tolerating the current dose, and gives you, practically speaking, a natural check-in rhythm. Think of it like adjusting the thermostat by one degree at a time rather than jumping straight to the maximum.

The ceiling is 15 mg. NICE's appraisal of tirzepatide (TA1026) evaluated the evidence up to that dose, and the SURMOUNT-1 trial, which involved 2,539 adults with obesity, reported around 20 to 21 per cent average body-weight reduction at 15 mg over 72 weeks. Not everyone reaches 15 mg, and not everyone needs to: your prescriber will assess the dose at which your results and tolerability balance is best for you.

If someone is converting from a different tirzepatide product, how does that work?

This is the question our prescribers hear regularly, particularly from people who were on a compounded tirzepatide formulation and want to move across to licensed Mounjaro pens. Compounded tirzepatide is typically drawn from a vial in units of a given concentration, for example 5 mg per ml. If you were injecting 0.5 ml of a 10 mg/ml solution, that is 5 mg, which corresponds to the 5 mg Mounjaro KwikPen. Simple arithmetic in that case. But concentrations vary by compounder, and without knowing the exact concentration of the vial you were using, the arithmetic produces the wrong answer.

The retatrutide-to-tirzepatide conversion page covers the related scenario of switching molecule entirely, which involves a different clinical calculation again. For all switch scenarios, a prescriber at a regulated UK service will look at your evidence of what you were taking before, your current weight, and how you have been tolerating treatment, before confirming the right Mounjaro starting point. That review exists to protect you, not to add friction.

If you are also curious about whether an oral alternative might suit you better, the tablet version of Mounjaro page explains what is and is not available in that format in the UK.

Does the chart differ between private treatment and the NHS?

The titration schedule itself is the same: the licensed dose ladder is set by the SmPC, not by who is paying. What differs is the access pathway and the pace of review. On the NHS, tirzepatide is currently being rolled out in phases under strict eligibility criteria, and appointments to review dose increases depend on the specialist service's capacity. Privately, through a regulated online pharmacy like nume, clinical review happens before each repeat order, at a pace that fits your schedule rather than a waiting list. If you order by noon on a working day and your prescriber approves the next step, dispatch goes out the same day.

That review before every repeat is not optional at nume; it is the mechanism that makes dose increases safe. A prescriber checks your weight, your response, and any side effects before confirming the next pen. It is also why our Mounjaro overview page describes this as a clinician-led service rather than a fulfilment operation.

Cost is a reasonable question when planning a multi-month titration. The weight-loss treatment overview puts pricing in context and explains what a single transparent price at a regulated service actually covers. Worth a read before you compare headlines.

Ready to talk through where you would start on the dose ladder? Start your free consultation and a GPhC-registered prescriber will review your details the same day.