How the tirzepatide weekly dosage chart works — and why each step matters

What the licensed schedule looks like, and what the trial data behind it shows

The SURMOUNT-1 trial, published in the New England Journal of Medicine, tested tirzepatide at 5 mg, 10 mg and 15 mg against placebo over 72 weeks in adults with obesity but without type 2 diabetes. Average body-weight reductions were substantial at every active dose, with the 15 mg group achieving around 20–21% in the primary analysis. Those results shaped the licensed dose range the MHRA approved for Mounjaro in the UK. You can read the detailed mechanism and indication summary on the NHS tirzepatide medicines page, which is a good first reference before a consultation.

The practical weekly schedule looks like this: four weeks at 2.5 mg, then four weeks at 5 mg, then onward in 2.5 mg steps at roughly the same four-week intervals (7.5 mg, 10 mg, 12.5 mg, 15 mg) with the prescriber deciding whether each increase is appropriate. If a particular step causes persistent or difficult side effects, the prescriber may hold the dose at the current level rather than advancing on schedule. More detail on how individual doses differ in practice is covered on our tirzepatide dose chart page.

One thing worth being clear about: the 2.5 mg pen is not where most people see significant weight loss. Its job is to prepare the body for what follows, reducing the nausea and GI discomfort that can accompany GLP-1 and GIP receptor activation when introduced abruptly at higher doses. The clinical programme built that ramp in deliberately.

How prescribers actually use the tirzepatide weekly dose in practice

NICE's appraisal of tirzepatide (TA1026, published December 2024) recommends using the lowest dose that produces adequate weight loss response, rather than automatically targeting the maximum. Prescribers follow the same logic: the goal is meaningful, sustainable benefit with the fewest side effects, not the highest number on the pen. A tirzepatide dosage chart is a useful orientation tool, but the titration itself is not something you manage by reading a chart, it requires clinical oversight at each step.

There are situations where a prescriber will hold a dose rather than advance it on the standard timetable: persistent nausea or vomiting that hasn't settled, significant fatigue, or any sign of a more serious reaction. Side effects are most common in the first few days after each dose increase and often ease within two weeks as the body adapts. Common GI effects (nausea, loose stools, reflux, slower digestion) are the ones most people encounter. Severe or persistent abdominal pain that reaches toward the back is a symptom that always warrants same-day medical attention, following the MHRA's January 2026 Drug Safety Update on pancreatitis risk with GLP-1 medicines.

Transfer patients (those moving from a previous provider) are reviewed against their current dose before any continuation or increase, because a responsible prescriber needs to see evidence that the prior titration was appropriate. Our process on how the weekly Mounjaro dose is managed explains what that looks like.

What arriving at a new dose actually looks like, and where the chart fits

When a new pen arrives (plain box, DPD tracking, nothing on the outside to tell a neighbour what's inside) the strength printed on the label is what your prescriber has approved for that supply. Each KwikPen contains four weekly doses of that strength. You inject once a week, on the same day if possible, rotating between the abdomen, thigh and upper arm. Storage is refrigerated at 2–8°C; for the precise window during which a pen can be kept at room temperature, the Patient Information Leaflet that comes with the pen is the right reference, not a webpage.

The dosage chart is a map, not a timetable you self-navigate. Some people reach 15 mg within six months; others stay at 10 mg for longer because that dose is doing what's needed. A small number never progress beyond 7.5 mg. For context on one specific step in the schedule, the Mounjaro 5 mg page covers what that dose represents clinically and what to expect. For a broader look at the treatment (including eligibility and cost) the Mounjaro overview is a good place to start. Cost is worth understanding before you begin; you'll find a clear breakdown on the Mounjaro pricing page. And if you're comparing dose formats across two or more specific levels, the 10 mg dosage chart and the Mounjaro dosage chart sit alongside this page as complementary references.

Tirzepatide is a prescription-only medicine. The dosage schedule above is a description of the licensed programme; the dose you should be on at any given point is something your prescriber determines. If you're ready to find out whether you're a suitable candidate, the right next step is a clinical consultation, not a chart.