Tirzepatide 30 mg: what the evidence says and why this dose isn't licensed in the UK

What the SURMOUNT-1 trial established about tirzepatide's upper dose

The landmark evidence for tirzepatide's licensed dose range comes from SURMOUNT-1, a 72-week phase 3 trial of 2,539 adults with obesity. Published in the New England Journal of Medicine, it tested 5 mg, 10 mg and 15 mg against placebo. At 15 mg, participants lost an average of around 20–21% of their body weight over the course of the study, a result that informed the MHRA's UK licensing decision and NICE's recommendation in technology appraisal TA1026.

Crucially, the trial did not test 20 mg, 25 mg or 30 mg. The dose range studied was chosen because higher doses in earlier phase studies produced diminishing additional benefit against a rising side-effect burden, particularly gastrointestinal symptoms. Regulators license what the evidence supports, not the highest dose a manufacturer could produce. So 15 mg became the ceiling because that is where the benefit-to-risk balance was established, not because a 30 mg tirzepatide pen was evaluated and rejected.

For people considering the treatment, this distinction matters. A preparation marketed at 30 mg has no clinical trial data behind it, no UK regulatory sign-off, and no licensed supply chain. That is a very different thing from a medicine whose upper limit has been thoroughly investigated.

The licensed UK dose schedule: how titration actually works

Under the Mounjaro licence, treatment begins at 2.5 mg once weekly for the first four weeks. That opening period is about letting your system settle, nausea is most common early on, and starting low reduces how disruptive it tends to be. Many people keep their pen in the fridge door and use the same day each week as a routine anchor.

From there, the prescriber guides the pace. Typical steps go 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg, usually in four-week increments, but only when each stage is well tolerated and clinically appropriate. You can read more about how individual dose decisions work on our tirzepatide dosing guide.

Not everyone reaches 15 mg, and reaching it is not a goal in itself. A prescriber may hold a patient at 10 mg indefinitely if that dose is working well and higher doses cause significant side effects. The schedule on the packet is a framework; the prescriber's clinical judgement is what shapes it for an individual. That process cannot happen without a formal assessment, which is exactly what a consultation with a registered prescriber provides.

What searches for '30 mg tirzepatide' usually reflect

When people search for tirzepatide at 30 mg, they are usually doing one of three things: comparing notes from another country (the US clinical programme tested different configurations), researching compounded or unlicensed preparations, or trying to understand whether a higher dose exists that they haven't been offered yet.

On compounding: in the UK, unlicensed compounded tirzepatide preparations have appeared, particularly during previous Mounjaro supply shortages. The MHRA has been clear that these sit outside the standard regulatory framework. They have no licensed dose schedule, no approved safety data at the strengths being produced, and no manufacturer accountability. A 30 mg compounded pen is not the same thing as a 15 mg licensed product; the comparison is not just about the number on the label.

Our Mounjaro overview covers the licensed product in full, including what genuine supply through a GPhC-registered pharmacy looks like. If you've been on treatment elsewhere and want to transfer, our prescribers will review your history and current dose before dispensing anything.

Eligibility for licensed tirzepatide treatment in the UK

The licensed indication covers adults with a BMI of 30 or above, or a BMI of 27 or above alongside at least one weight-related condition such as high blood pressure, type 2 diabetes, high cholesterol or obstructive sleep apnoea. Under UK clinical guidance, lower BMI thresholds apply for some ethnic backgrounds. A BMI figure alone doesn't determine approval; the prescriber weighs the full clinical picture at assessment.

NICE's TA1026 sets a higher NHS threshold (BMI of 35 or above with at least one qualifying comorbidity), and NHS access is being phased in gradually. For many people the private route is the practical one right now. The starting point, either way, is the same: a clinical consultation. Understanding the starter dose and what the initial weeks involve gives a clearer picture of what beginning treatment actually looks like.

If cost is part of your thinking, the Eli Lilly UK price changes in 2025 affected what providers charge at different dose levels, worth reading before comparing quotes, and our page on 1 mg tirzepatide explains how investigational dosing below the licensed schedule differs from the approved treatment pathway. Our clinical team reviews every consultation personally before any prescription is issued.