How many mg of tirzepatide do you take per week?

What is the starting dose of tirzepatide, and why isn't it higher?

The 2.5 mg weekly dose exists for one reason: to let your digestive system settle. Tirzepatide works partly by slowing how quickly food leaves the stomach, and jumping straight to a higher dose makes nausea and vomiting considerably more likely. The 2.5 mg pen is the first four weeks of treatment, it does a job, but that job is adjustment, not weight loss. Most people don't notice dramatic appetite changes at this level, which can feel frustrating if you were hoping for quick results. That frustration is understandable, and it's one of the most common things our prescribers hear.

After four weeks, the prescriber typically moves the dose to 5 mg weekly, provided it's been well tolerated. The 5 mg tirzepatide pen is where most people start to notice a meaningful reduction in appetite. From there, the schedule continues in 2.5 mg increments: 7.5 mg, 10 mg, 12.5 mg, and 15 mg, each held for at least four weeks. The NHS tirzepatide medicines page confirms this titration schedule for patients starting treatment.

Not everyone reaches 15 mg. If a lower dose produces good results with manageable side effects, the prescriber may keep things there. The ceiling is a maximum, not a target.

What dose of tirzepatide is used for weight management in clinical trials?

The SURMOUNT-1 trial (which ran for 72 weeks and involved 2,539 adults with obesity) tested the 5 mg, 10 mg, and 15 mg maintenance doses. Average body-weight reductions at the highest dose reached around 20 to 21%, a figure cited by NICE's technology appraisal of tirzepatide (TA1026) as part of its evidence review. The 15 mg cohort consistently showed the largest average loss, though the 10 mg group also produced substantial results. Individual responses varied considerably across all dose groups.

It's worth being clear about what those percentages mean in practice: they're averages from a controlled trial, alongside a structured lifestyle programme, over a year and a half. Results in routine clinical use differ from person to person. For a fuller look at how tirzepatide is used in the UK, the Mounjaro treatment overview covers the evidence alongside eligibility and access routes.

The trial did not include a 2.5 mg maintenance arm, that dose is established in the licensed schedule purely as an introduction. By the time trial participants reached their maintenance dose, they had already titrated through the lower steps.

Does the amount of tirzepatide per week ever need to come down?

Yes. If side effects at a given dose are difficult to manage, the prescriber can hold the current dose for longer before increasing, or step back to the previous level. This isn't treatment failure, it's the schedule working as intended. The prescriber's job is to find the highest dose you tolerate well, not to push the number as high as possible.

If you're curious about what the volume inside each pen looks like at different doses, the detail varies: the volume in the 5 mg pen and the volume in the 10 mg pen differ from the starter strength, and each pen delivers all four weekly doses from a single device. For storage, handling and exactly how long a pen remains usable outside the fridge, the Patient Information Leaflet is the definitive source, those details sit with the prescriber and the leaflet, not with general content.

Missing a dose, timing of injections, and what to do if a dose is skipped should all be discussed with your prescriber. The Patient Information Leaflet also covers this in detail. The right person to ask about your specific dose is the clinical team, not a search result. You can reach ours through the aftercare contact page any day of the week.

How does the weekly mg of tirzepatide compare to what's in each pen?

Each Mounjaro KwikPen contains four weekly doses. So a 5 mg pen delivers 5 mg per weekly injection, four times over, before it's finished. The same applies at every strength: the number on the pen label is the weekly dose, not the total content. At 15 mg weekly, the pen holds 60 mg in total across those four uses.

A quick note on the volume question that often follows: how many millilitres corresponds to a given dose depends on the concentration of each pen, and it differs by strength. The 15 mg volume guide breaks that down for the highest dose; the 2.5 mg equivalent is a useful starting reference for people just beginning treatment. These figures are based on information in the published prescribing data.

Cost context is worth considering here too. The price of tirzepatide changes as you move up the dose ladder, because the pens are priced differently by strength. The Mounjaro pricing guide covers what to expect at each level through a private prescription. For those eligible, NHS access is phased, most people currently accessing tirzepatide in the UK do so privately through a regulated online pharmacy. The right first step is a free consultation: check your eligibility with our prescribers.