What are the dosages for Mounjaro, and how does the schedule work?

Step 1, Why 2.5 mg comes first, even though it feels low

A lot of people expect their first Mounjaro pen to be the dose that drives results. That's a reasonable assumption, and letting go of it makes the early weeks a lot less frustrating. The 2.5 mg dose exists to give your digestive system a chance to settle into tirzepatide's way of working (slowing gastric emptying, signalling fullness, nudging appetite down) before the dose climbs. At 2.5 mg, nausea and other gastrointestinal effects are least likely to be disruptive. For most people, the first four weeks pass without serious side effects, which sets a good foundation for the increases to come. Your prescriber decides whether you move up after that first pen; the timetable is clinical, not automatic. The full Mounjaro overview explains how tirzepatide works as a dual GIP and GLP-1 receptor agonist, which is the mechanism behind that appetite shift.

Step 2 (Moving through the middle doses: 5 mg to 10 mg

Once you've cleared the starter dose, the schedule typically steps through 5 mg, 7.5 mg, and 10 mg in roughly four-week intervals) though your prescriber may hold a dose longer if side effects are present or if you need more time to stabilise. Each increase is a clinical decision, not a calendar event you can self-trigger. The 5 mg pen is often where people notice the appetite-suppressing effect becoming more tangible: meals feel smaller, the habit of snacking loosens a little. The 7.5 mg and 10 mg steps tend to build on that. It is worth knowing that the licensed dosing schedule is designed so that tolerability improves before potency increases, which is why rushing the titration is not recommended. For a detailed look at dose-specific evidence and how the numbers differ by pen, the tirzepatide dose breakdown covers that in full. Private treatment costs also shift by dose; the Mounjaro price comparison sets out the UK market context honestly.

Step 3 (The higher doses: 12.5 mg and 15 mg

The upper two doses on the schedule are where the largest average weight reductions were observed in the SURMOUNT-1 trial) around 20–21% at 15 mg over 72 weeks, as reported in the NEJM SURMOUNT-1 paper. That figure is a trial average across thousands of participants; individual results vary. The 12.5 mg pen sits just below that ceiling and is the dose many people reach and maintain on long-term treatment. Reaching 15 mg is not a requirement: the right maintenance dose is the highest one you tolerate well, which may be below the maximum. The 15 mg pen information covers what to expect at that level. NICE's appraisal of tirzepatide notes that if weight loss falls below 5% after six months at the highest tolerated dose, continuing treatment should be reviewed, so results at each dose inform whether the titration continues or holds. According to NICE TA1026, tirzepatide is recommended for adults with a BMI of 35 or above alongside at least one weight-related health condition, with lower BMI thresholds applying for some ethnic backgrounds under UK guidance.

What stays constant across every dose

Regardless of which pen you are using, several things remain the same: the KwikPen format, the once-weekly injection day (ideally consistent), the rotation of injection sites (abdomen, thigh, upper arm), and the requirement for a valid prescription reassessed before each repeat supply. Storage stays the same too, refrigerated at 2–8°C, with a limited room-temperature window set out in the Patient Information Leaflet; always check the leaflet for the exact figures rather than relying on memory. Side effects follow a similar GI-led pattern at every dose (nausea, changes in bowel habit, reduced appetite, occasional fatigue) though they tend to be most pronounced around each step up and often settle within the first couple of weeks at the new level. Our prescribers at nume review your case before every repeat, so any side-effect concerns can be addressed before the next pen is dispatched rather than left to manage alone. If you have questions in between, the FAQs cover the most common ones, and the team is available for aftercare support seven days a week. When you are ready to understand whether the schedule is right for your situation, check your eligibility with a free consultation.