Tirzepatide doses: the full schedule from 2.5mg to 15mg

You've just been told you're starting on 2.5mg, here's why that's exactly right

Almost everyone feels a flicker of impatience when they hear that the first dose is 2.5mg. If the full-strength dose can cut body weight by a fifth, why spend weeks at a fraction of that? It's a fair question, and the answer matters.

The 2.5mg strength is a settling-in dose. Tirzepatide slows how quickly food moves through your stomach and acts on appetite-regulating signals in the gut and brain. That's powerful, and for most people it takes a few weeks for the body to adjust without significant nausea or digestive disruption. Starting low isn't timid prescribing; it's the reason most people tolerate the medicine well enough to reach the doses where the clinical results really accumulate.

Each pen contains four pre-set weekly injections at a single strength, so one pen covers roughly a month. After that month your prescriber reviews how you're getting on before moving you to the next rung. You can read more about how individual dose decisions are made and what factors influence the pace of titration.

One thing our prescribers hear regularly: people wondering whether they're on the "wrong" dose if they don't feel dramatic change in week one. The first pen's job is adjustment. Effects build.

The six doses of tirzepatide (what the numbers actually mean

The six UK strengths) 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg, map onto a structured titration pathway, typically moving from one strength to the next every four weeks. The figures refer to the amount of tirzepatide in each injection, not the volume of liquid in the pen. For readers wondering about tirzepatide doses in units or millilitres, the pre-filled KwikPen delivers a fixed volume per injection; the dose in mg is set by the pen's formulation, so you don't measure or adjust anything yourself.

The 5mg dose is often where people begin to notice a more meaningful shift in appetite, and our tirzepatide 5mg page covers what to expect during that phase in detail. The 15mg dose is the maximum licensed strength and the one associated with the strongest clinical results; in SURMOUNT-1, a 72-week randomised trial published in the New England Journal of Medicine, participants on 15mg achieved an average body-weight reduction of around 20–21%. Not everyone needs or reaches 15mg, the right maintenance dose is whichever strength works well for you with acceptable tolerability, as judged by your prescriber.

If you're comparing overall treatment options, the Mounjaro overview sets the full picture alongside eligibility and what's involved in getting started.

Who the licensed dose schedule applies to, and when a prescriber might pause

The UK licence covers adults with a BMI of 30 or above, or a BMI from 27 upward alongside at least one weight-related condition such as high blood pressure, type 2 diabetes, high cholesterol, or obstructive sleep apnoea. Lower BMI thresholds can apply for some ethnic backgrounds under UK clinical guidance. BMI alone never determines the outcome of a consultation, your prescriber looks at the whole picture, including other medicines you take and your medical history.

Dose increases aren't automatic. If side effects are significant at a given strength, the prescriber may hold at that dose for longer rather than stepping up on a fixed calendar. That flexibility is built into the licensed schedule deliberately. The NHS guidance on weight-management injections explains the clinical principles that underpin this titration approach.

A note on situations that require particular care: tirzepatide is not recommended during pregnancy, while breastfeeding, or for anyone trying to conceive, and it is not licensed for under-18s. A history of medullary thyroid carcinoma or certain gastrointestinal conditions means the prescriber will need more information before any dose is considered.

Understanding what the private cost of treatment looks like across doses is something many people factor into planning. The Mounjaro price page covers how UK private pricing works, including what a legitimate prescription-inclusive price should contain.

Staying safe as your dose increases

The most common side effects with tirzepatide are gastrointestinal: nausea, loose stools, constipation, indigestion, and burping. These are most noticeable at the start of treatment or after a dose step-up, and they typically ease within a couple of weeks as the body adjusts. Eating smaller portions, staying well hydrated, and avoiding very high-fat meals all help.

There are symptoms that need prompt medical attention rather than watchful waiting. Severe stomach pain that radiates toward the back, with or without vomiting, can be a sign of pancreatitis, the MHRA issued a dedicated safety update on this in January 2026 and anyone who experiences it should seek urgent care. Signs of a serious allergic reaction, significant dehydration, or sudden changes in vision also warrant immediate contact with a healthcare professional.

If you want to explore treatment alongside support from our clinical team, checking your eligibility is the place to start, consultations are free, and a prescriber reviews every application personally.