Mounjaro dosage guide: understanding how the schedule is set

The decision your prescriber is actually making

When a prescriber sets your Mounjaro dose, they're balancing two competing pressures: moving quickly enough to get clinical benefit, and slowly enough that your body adjusts without unnecessary discomfort. The six UK strengths (2.5, 5, 7.5, 10, 12.5 and 15 mg) are not arbitrary. Each step was tested across the SURMOUNT clinical programme, involving thousands of adults, to establish how much benefit each level adds and what the tolerance profile looks like.

The 2.5 mg pen you receive first isn't a treatment dose in any meaningful sense. It exists to reduce the nausea and digestive disruption that tends to peak when you introduce a GLP-1 or dual-agonist medicine. Once four weeks have passed and your prescriber is satisfied you're tolerating it, the conversation about moving to 5 mg begins. From there, the same logic applies at every rung. There is no universal pace, some people spend longer at a given strength because they're tolerating it well and their prescriber is satisfied there's no reason to hurry.

The ceiling is 15 mg. In the SURMOUNT-1 trial, average body-weight reduction at that dose was around 20–21% over 72 weeks, as reported in the New England Journal of Medicine. Whether you reach that ceiling depends entirely on clinical review, and on your response at each stage.

What shapes the pace of your titration

Three things tend to influence how quickly a prescriber is comfortable moving you up. First, tolerability: persistent nausea, vomiting or diarrhoea at the current dose are a strong signal to hold rather than escalate. Second, evidence of progress: a prescriber reviewing a repeat order will typically look at how your weight, and your response to treatment, are tracking. Third, your overall health picture, other medicines you take, any relevant conditions, and whether you're getting the lifestyle support alongside the prescription.

Timing can play a practical role too. If your supply runs late because you ordered just after the 12pm cut-off on a bank holiday Friday, there may be a short gap, that's worth planning around, especially near Christmas or Easter. It's a mundane detail, but an unplanned break in treatment is something your prescriber would want to know about.

The Mounjaro dosage page looks in more detail at what the full schedule looks like for most people, including what happens if a dose is missed. Our clinical team follows the SmPC exactly when making these calls.

Where the maximum dose fits into the picture

Not everyone reaches 15 mg. The licensed indication allows for treatment to continue below the maximum if you're tolerating a lower strength well and achieving meaningful results. NICE's guidance on tirzepatide, published in TA1026, notes that if less than 5% weight loss has occurred after six months at the highest tolerated dose, continuing the medicine should be reviewed. That's not a punishment, it's a sensible clinical checkpoint, and the same principle appears in prescribing practice globally.

For a detailed look at what 15 mg specifically involves, the maximum Mounjaro dose page covers what the evidence says and how prescribers approach that decision. Meanwhile, people starting out often ask specifically about the 5 mg step, you can read about that on the Mounjaro 5 mg page.

What no guide can replace is a clinical conversation. The dose schedule is a framework; your prescriber applies it to you specifically. If you haven't yet spoken to a prescriber about whether tirzepatide is appropriate for you, or you're weighing it against other weight-loss treatment options, that's the right starting point.

Getting your dosage reviewed safely

Every repeat order at nume is reviewed by a GPhC-registered Independent Prescriber before it's approved. That means a clinician reads your case again, your current dose, your progress, any concerns you've flagged. No automation makes that call. If you're transferring from another service and requesting a dose increase, you'll be asked for evidence that you've been on your current dose for the appropriate period, which is standard clinical practice rather than bureaucracy for its own sake.

The KwikPen delivers four weekly doses per pen, which makes keeping track straightforward. Storage matters: Mounjaro pens are kept refrigerated between 2 and 8°C, and the Patient Information Leaflet sets out the exact room-temperature window if you need to take it out of the fridge, always check that rather than relying on a figure you've seen online. For a full breakdown of how each strength fits into the escalation schedule, our dosage guide for tirzepatide walks through what to expect at each stage. For questions about what the pen itself looks like and how doses are measured, the Mounjaro pens and dosage page is a practical reference.

If you'd like to understand the cost of treatment across the dose range, the Mounjaro prices page sets out what private treatment typically involves in the UK, without the small print. When you're ready to speak to a prescriber, check your eligibility and start your free consultation.