Tirzepatide Dosing Conversion Chart for Weight Loss

What the official schedule looks like, and why it's structured this way

The NICE appraisal of tirzepatide (TA1026) and the medicine's Summary of Product Characteristics on the eMC set out a six-rung schedule: 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg. Each rung is typically held for around four weeks before the prescriber considers moving up. The design is deliberate. Nausea, indigestion and similar gastrointestinal effects are most pronounced when the dose changes; giving the body four weeks at each level reduces that burden considerably. Skipping rungs or rushing the schedule does not produce faster weight loss, it produces more side effects and, in most cases, an unnecessary pause while things settle back down.

The 2.5 mg pen is the entry point for almost everyone. Think of it as the adjustment phase rather than the treatment phase. Appetite suppression at this level is modest; the clinical value is establishing tolerance. From 5 mg onwards, the weight-loss effect becomes more noticeable for most people, and the evidence from SURMOUNT-1 (which followed over 2,500 adults across 72 weeks) shows the strongest average results at the upper doses. Not every patient reaches 15 mg, and that's fine; a prescriber assesses the highest tolerated dose, which may be 10 mg or 12.5 mg for some people.

One quick check worth doing: the Mounjaro dosing chart on this site lays out the same schedule visually, including the four-week timing blocks.

What 'conversion' usually means, and where it applies

Searches for a tirzepatide conversion chart often come from two distinct groups. The first are people switching from semaglutide (Wegovy) to tirzepatide and wanting to know which tirzepatide dose corresponds to their current semaglutide dose. The honest answer is that no officially validated equivalence table exists. The two medicines work through different receptor pathways (tirzepatide activates both GIP and GLP-1 receptors, while semaglutide activates GLP-1 only) and their dose scales are not directly comparable in milligrams. In SURMOUNT-5, the head-to-head trial published in the New England Journal of Medicine in 2025, tirzepatide produced greater average weight reduction than semaglutide 2.4 mg over 72 weeks, but this reflects mechanism and the dose used in that specific protocol, not a simple unit conversion.

The second group are people who have seen references to compounded or unlicensed tirzepatide, sometimes listed in different units (micrograms, mcg), and want to compare. Unlicensed compounded versions are not the same product; the dosing conventions differ, and any comparison is unsafe without specialist clinical guidance. The only relevant schedule for Mounjaro (the UK-licensed tirzepatide brand) is the one set by the MHRA-approved SmPC. A broader look at retatrutide-to-tirzepatide comparisons follows the same logic: different molecules, no validated conversion table.

For anyone considering a switch, the right route is a clinical conversation, not a chart.

Who the dose schedule is designed for, eligibility in brief

The licensed indication covers adults with a BMI of 30 or above, or 27 and above alongside at least one weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes or obstructive sleep apnoea. Under UK guidance from NICE TA1026, lower BMI thresholds apply for South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean backgrounds, the adjustment is 2.5 kg/m² throughout. BMI alone does not guarantee suitability; the prescriber looks at the full clinical picture, including medicines that might interact and any conditions where tirzepatide is not appropriate.

On the NHS, access to tirzepatide through the phased rollout is currently restricted to specific BMI and comorbidity thresholds that are tighter than the licensed criteria. For people who do not meet those thresholds or prefer not to wait, a regulated private pharmacy is the alternative. The tirzepatide overview on this site covers the eligibility picture in more detail, and the Mounjaro page explains the licensed product itself. If cost is a consideration, the private Mounjaro pricing guide walks through what legitimate treatment typically costs in the UK.

Practical notes on using the dose schedule safely

A few things the chart alone cannot tell you. Storage matters: each Mounjaro KwikPen must be refrigerated at 2–8°C, and there is a limited window during which it can be kept at room temperature, the exact figure is in the Patient Information Leaflet, not something to estimate from memory. Injection sites rotate between the abdomen, thigh and upper arm; using the same spot repeatedly increases the chance of a localised skin reaction.

Side effects cluster around dose changes. Nausea, loose stools and bloating tend to peak in the first week or two after stepping up, then ease. The NHS tirzepatide medicines page lists the full side-effect profile; the one that warrants urgent attention is severe, persistent stomach pain that spreads to the back, which can be a sign of pancreatitis. The MHRA issued a specific Drug Safety Update on this in January 2026, worth reading if you are on treatment or about to start.

The Mounjaro weight-loss chart brings together the dose schedule and the corresponding average weight-loss data from SURMOUNT-1, which is useful context for setting realistic expectations. The Mounjaro conversion chart page looks at the specific question of switching from or to Mounjaro in more depth.

When you are ready to explore whether tirzepatide is clinically appropriate for you, a real prescriber (not an algorithm) reviews your consultation the same day. Start your free consultation with our clinical team and get a considered answer, not just a number on a chart.