Reading a Tirzepatide Peptide Dosing Chart: What the Evidence Says

What SURMOUNT-1 tells us about dose and weight loss

The SURMOUNT-1 trial, published in the New England Journal of Medicine, enrolled 2,539 adults with obesity and no diabetes over 72 weeks. All three active doses (5 mg, 10 mg and 15 mg) produced meaningful weight loss, but the relationship was clearly dose-dependent: the 15 mg group reached an average reduction of around 20–21% of starting body weight. That figure matters when you're reading any tirzepatide dosing chart, because it anchors what the licensed end-dose can realistically achieve under trial conditions alongside a reduced-calorie diet and increased activity.

Crucially, the trial did not start participants at 5 mg. The published protocol began at 2.5 mg for the first four weeks, stepping up in 2.5 mg increments roughly every four weeks thereafter. The 2.5 mg opening dose isn't doing much therapeutically. Its job is to settle the gastrointestinal system, nausea, loose stools and reflux are most pronounced when the medicine is introduced, and a slow ascent keeps most people on treatment long enough to reach a dose that delivers real benefit.

Dose-response patterns like these are why the NHS medicines information for tirzepatide describes titration rather than a fixed single dose. The schedule in a chart is a map; a prescriber decides your current position on it.

Why many online 'peptide dosing charts' don't apply to Mounjaro

The phrase "peptide dosing chart" often surfaces in the context of research peptides: unlicensed, compounded or grey-market versions of tirzepatide sold outside the pharmaceutical supply chain. These products are not Mounjaro. They have not passed MHRA assessment, they are not manufactured to Good Manufacturing Practice standards, and the dosing figures that accompany them (often expressed in milligrams drawn up from a vial) are unrelated to the KwikPen schedule that clinical trials tested.

The MHRA has warned publicly about unlicensed and counterfeit weight-loss products sold online. In 2025, enforcement operations seized around 20 million doses of illegally traded weight-loss medicines (approximately £45 million street value), including the first known illicit UK manufacturing site producing counterfeit tirzepatide pens, raided in Northampton. Applying a research-peptide chart to Mounjaro, or vice versa, is therefore not just unhelpful, using an unlicensed product based on an unvalidated chart is a genuine clinical risk. If you've come to this page from that direction, our tirzepatide peptide mixing chart explains exactly how vial-based dosing figures are constructed, which helps clarify why they differ so fundamentally from the licensed KwikPen schedule.

You can explore the broader context of tirzepatide as a peptide medicine to understand the distinction between the licensed and unlicensed landscape in more detail.

The licensed dosing framework, broken down

NICE's appraisal of tirzepatide (TA1026, published December 2024) reflects the same stepped structure the trials used. The framework, as approved by the MHRA for the KwikPen, works as follows: treatment opens at 2.5 mg once weekly. After approximately four weeks, if 2.5 mg is tolerated, the prescriber moves the patient to 5 mg. Subsequent steps to 7.5 mg, 10 mg, 12.5 mg and finally 15 mg each require a similar period at the prior dose. Not everyone reaches 15 mg, some people do well at a lower maintenance dose, and tolerability at each step informs whether the prescriber moves up, holds or adjusts.

A visual dosing chart would show six rows (one per strength) and a horizontal time axis. Each step occupies roughly four weeks. The full ascent to maximum dose takes around five months if each step is tolerated without delay. That timeline matters for practical planning, someone starting treatment around a holiday or a busy work period might find the 7.5 mg or 10 mg step lands at an inconvenient moment, and a prescriber can factor that in. It's worth mentioning if timing matters to you.

What no static chart can capture is the clinical layer: NICE recommends reviewing continuing treatment if less than 5% weight loss is achieved at the highest tolerated dose after six months. That threshold is a clinical decision, not a data point on a grid. For a practical comparison of how Mounjaro's schedule sits alongside Wegovy's, the Mounjaro dosing chart page covers the two side by side.

What to do if you have questions about your own titration

A chart is useful for orientation. It tells you where the schedule goes, and it helps you understand why you're on a particular dose at a given point. What it doesn't replace is the clinical relationship. Prescribers at a GPhC-registered service review your response before each repeat (weight, tolerability, any concerns) and that review is what makes a step-up safe rather than automatic.

If you're comparing providers or thinking about starting treatment, the tirzepatide overview covers eligibility, the consultation process and what to expect from the licence. The tirzepatide chart page has a fuller breakdown of the dose timeline if you want the schedule in plain visual form. For a sense of how pricing works across the treatment journey (given that each dose level is a different pen) the context around Mounjaro pricing in the UK is worth reading alongside your treatment decisions. And if any side effect or symptom feels unclear, the Patient Information Leaflet in your pen box, and your prescribing team, are the right first call, not a chart.

When you're ready to have a prescriber look at your own situation properly, you can speak to our prescribers through a free consultation, reviewed the same day by a GPhC-registered clinician, never by an automated system.