What strength of Mounjaro is used for weight loss?

You've heard '15 mg' and wondered if you'll ever get there

That's an understandable place to be. A lot of people researching Mounjaro strengths have seen the headline trial figures attached to the highest dose and are quietly hoping that's where they'll land. The reality is kinder than you might expect, though the route there is deliberate and unhurried, by design.

Treatment begins at 2.5 mg. That first pen's job is not weight loss; it's settling your system into the medicine. Nausea and other gastrointestinal effects are most likely to surface when tirzepatide is introduced or when the dose rises, and starting low gives those effects the best chance of staying mild. After four weeks, a prescriber reviews how things are going and, if all is well, moves the dose to 5 mg. The pattern continues in roughly 4-week steps: 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg. There is no skipping rungs. You can read more about how the dose schedule relates to weight loss outcomes if you want the fuller picture.

Not everyone reaches 15 mg, and that's fine. Some people achieve meaningful weight loss and good tolerability at a lower strength and stay there. Others push toward the maximum and find it suits them well. The strength that becomes your maintenance dose is the highest one your body tolerates well while continuing to produce a benefit, a clinical judgement, not a personal milestone.

What the six strengths look like in practice

Each strength of Mounjaro comes in its own pre-filled KwikPen. One pen contains four doses (one per week) so you're ordering monthly. If you want to understand how each step fits into the overall titration journey, our guide to Mounjaro strength covers the six UK-licensed options, 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg, in detail, and if you want a detailed breakdown of how each one fits into the schedule, our guide to Mounjaro strengths covers each step in turn.

It is worth being clear about what 'the 15 mg dose' means in evidence terms. The SURMOUNT-1 trial (2,539 adults over 72 weeks) reported an average body-weight reduction of roughly 20–21% at 15 mg. That's a population average from a rigorous clinical setting, and individual results varied around it. At lower maintenance doses, the average reductions were smaller but still clinically meaningful: around 15% at 10 mg and around 12% at 5 mg, again as trial averages. The point is that every strength in the licensed range has evidence behind it; the aim is the right strength for you, not the highest number on the box.

Storage is the same across all six: refrigerated at 2–8°C until you're ready to use the pen. Room-temperature windows exist, but the exact durations differ slightly, so for that detail the Patient Information Leaflet that comes with your specific pen is the only reliable source.

Why a prescriber, not a search result, answers this question

Choosing a Mounjaro strength is genuinely a clinical task. A prescriber looks at your starting weight, any conditions you're managing, what other medicines you take, and how you responded to the previous dose. Eligibility under the UK licence covers adults with a BMI of 30 or above, or 27 and above when a weight-related condition (such as hypertension, type 2 diabetes or obstructive sleep apnoea) is present. Lower BMI thresholds can apply for some ethnic backgrounds under UK guidance. But meeting the BMI number is only the starting point; the whole picture matters.

If you're wondering whether Mounjaro is appropriate for your situation at all, the question of which strength you might need is really the same as asking whether the medicine is right for you, and that needs an honest conversation with a clinician. Our clinical team reviews every consultation personally. If you're also curious about what strength tirzepatide comes in, that page gives a clear overview of the available options across the range. For context on the broader cost of private treatment, the Mounjaro price page sets out what to expect without hiding figures in small print.

At nume, a GPhC-registered Independent Prescriber (a real person) reads every consultation the same day. If you're ready to find out whether tirzepatide is clinically suitable for you, and at what starting point, the next step is a free assessment.

Speak to our prescribers by starting your free consultation.