90 mg Tirzepatide: Understanding the Real Dose Schedule

Step 1: Where the 90 mg figure most likely comes from

A question our prescribers hear most weeks is some version of: 'I read about a high-dose version, is there something stronger than what I've been prescribed?' The 90 mg number tends to have one of two origins. The most common is simple arithmetic: four weekly doses of the maximum licensed 15 mg pen add up to 60 mg across a four-week supply, and some users seem to have multiplied further or confused weekly and monthly figures. The other source is unregulated sellers abroad, where tirzepatide pens are sometimes relabelled with non-standard concentrations. Neither represents a real UK-licensed product.

The licensed maximum in the UK is a single 15 mg injection once a week, confirmed in the Mounjaro Summary of Product Characteristics published on the eMC. Any product claiming to deliver 90 mg in a single dose sits outside that licence entirely. If a seller is offering doses at that level, it is a strong signal that the product has not been through UK regulatory approval.

Understanding the actual schedule matters practically. You can explore the full tirzepatide dose guide on the nume site, which sets out each step and the clinical logic behind them.

Step 2: The real dose escalation, from start to maintenance

Tirzepatide treatment in the UK begins at 2.5 mg. That starter dose is not intended to drive significant weight loss straight away, its job is to let your digestive system adjust before the therapeutic doses begin. For most people the 2.5 mg starting pen is taken for the first four weeks, after which the prescriber typically moves to the 5 mg strength, which is where the first meaningful therapeutic effect is usually felt.

From there, increments continue in 2.5 mg steps every four weeks: 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg. Not everyone reaches 15 mg. Some people find a lower maintenance dose both effective and more comfortable on the stomach; the prescriber reviews progress and tolerability before any increase. The SURMOUNT-1 clinical trial, which involved 2,539 adults over 72 weeks and is published in the New England Journal of Medicine, reported average body-weight reductions around 20–21% at the 15 mg dose, a figure that has shaped most public discussion of tirzepatide's ceiling.

What no clinical protocol describes, in the UK or elsewhere, is a 90 mg dose. The figure has no licensed foundation.

Step 3: What to do if you've encountered a 90 mg product

If you have seen tirzepatide marketed at 90 mg (on social media, via a messaging-app seller, or through an unfamiliar website) the MHRA asks patients to report it. The Yellow Card scheme at yellowcard.mhra.gov.uk accepts reports of suspect medicines as well as side effects, and the regulator has used those reports to pursue enforcement action, including the seizure of counterfeit tirzepatide pens.

The practical test for any online pharmacy is straightforward. Legitimate UK pharmacies are registered with the GPhC; you can check any provider's registration at the GPhC pharmacy register. A pharmacy offering tirzepatide at doses not listed in the UK licence, or supplying it without a valid prescription following clinical assessment, is operating outside the law. That risk is worth naming plainly: counterfeit pens have in some cases contained insulin rather than tirzepatide, with potentially serious consequences for people without diabetes.

If you are wondering what genuine Mounjaro costs through a private regulated pharmacy, the background on UK tirzepatide pricing explains how the market has moved and what to expect. The right question for any treatment, though, is not which dose is highest, it is which dose a prescriber considers appropriate for you.

Step 4: Discussing dose with a prescriber

Tirzepatide's titration schedule is a clinical decision, not a personal choice. Increasing a dose before the body has adjusted increases the risk of nausea, vomiting and other gastrointestinal side effects without necessarily improving outcomes. People who are curious about the very beginning of the schedule can read more about 1 mg tirzepatide, including the clinical context for sub-therapeutic starting doses, before reviewing the full Mounjaro overview, which covers the mechanism and trial evidence in more depth if you want the wider picture before starting a consultation.

Transfers from another service, or people who have been prescribed a specific strength elsewhere and want to continue, will be asked to provide evidence of their current dose. That evidence check exists because jumping straight to a high dose without the preceding clinical record raises safety concerns, it is one of the reasons genuine clinical oversight matters at every stage, not just at the start.

The NHS provides patient-level information on tirzepatide, including its licensed doses and common side effects, on the NHS tirzepatide medicines page. That is a reliable first reference if you want to cross-check anything you have read elsewhere.

If you have questions about whether tirzepatide is suitable for you, or which dose makes sense given your history, the right step is a clinical conversation. You can start your free consultation with a GPhC-registered prescriber; there are no questionnaires processed by software, a real clinician reads your answers the same day.