Your Mounjaro diary: what clinical evidence tells us about tracking weight loss

What SURMOUNT-1 tells us about the timeline you are tracking

The SURMOUNT-1 trial enrolled 2,539 adults with obesity and followed them for 72 weeks. Average weight reduction at the 15mg dose was around 20–21% of starting body weight, but that figure came at the end of a journey that included a slow starter phase, a dose-titration period and a plateau before the curve began to steepen again. Participants who tracked results only against their starting weight sometimes found early weeks discouraging, because the body's response to tirzepatide builds gradually as the dose increases.

This is exactly why a structured Mounjaro diary in the UK context is clinically useful. Recording your weight on the same day each week, before breakfast, on the same scales, smooths out the natural noise caused by water retention, menstrual cycle changes and the varied timing of meals. If you also note your dose alongside each entry (the 2.5mg starter, then 5mg, and so on as titrated by your prescriber) patterns become readable rather than random. Our step-by-step Mounjaro guide explains how the titration schedule works in practice.

One small practical note: many people tuck their spare pen in the fridge door and weigh themselves on injection morning, immediately linking the habit of measurement to the routine of treatment. That kind of pairing tends to stick.

What belongs in a Mounjaro diary beyond the number on the scales

Weight is the headline figure, but it tells an incomplete story. The NHS tirzepatide medicine page lists common side effects that include nausea, diarrhoea, constipation and indigestion, all of which can fluctuate week to week, especially in the first few months. A brief daily note of how your digestion felt, whether your appetite changed and how your energy held up creates a timeline your prescriber can read at a glance.

Waist circumference is worth adding monthly. Clinical research consistently shows that changes in abdominal fat often precede changes in total body weight, so the tape measure sometimes tells a more encouraging story than the scale mid-treatment. Noting your injection site each week (abdomen, thigh, upper arm) helps you rotate correctly and flag any persistent redness or swelling to your prescriber.

If you take other medicines, a diary is also a useful place to record any new symptoms that coincide with a dose change, and if you want to understand how a specific medicine interacts with tirzepatide, you can read about diazepam and Mounjaro as one example of how those questions are approached. This becomes particularly relevant if you are on oral contraceptives, because UK guidance advises adding a non-oral method during the first four weeks of treatment and after each dose increase due to possible reduced absorption. Our full Mounjaro overview covers this and other interactions in detail.

When your diary entries should prompt you to contact your prescriber or seek urgent help

Most entries in a Mounjaro diary will be unremarkable, and that is fine. Gradual, steady progress interspersed with occasional plateau weeks is the normal pattern seen across the SURMOUNT programme. There are, however, entries that should prompt action rather than patience.

Severe stomach pain that extends towards your back (especially if accompanied by vomiting and not settling within a few hours) requires urgent medical attention. In January 2026, the MHRA issued a Drug Safety Update for GLP-1 medicines specifically highlighting acute pancreatitis as a known, serious, though infrequent side effect. Writing the date, severity and duration of any such episode in your diary before you contact a clinician means you can give an accurate account rather than a rough approximation. Similarly, note any allergic symptoms (rash, swelling, breathing difficulty) or significant mood changes, and contact your GP or call 111.

The Yellow Card scheme at yellowcard.mhra.gov.uk lets you report suspected side effects directly to the MHRA, your diary entries are exactly the kind of dated, specific information the scheme relies on to build a safety picture across thousands of patients.

Using your diary to get the most from clinical reviews at nume

At nume, at nume, every repeat supply requires a fresh clinical assessment. When you present for review, whether digitally or via our prescribing team, a clear record of your progress makes that review faster and more useful. A prescriber who can see that your weight has been stable for six weeks, that nausea peaked at week three then resolved, and that you have been managing injections without issue, is better placed to make a confident clinical decision than one working from memory alone.

People who keep a consistent Mounjaro diary in the UK also tend to notice their own habits more clearly, the weeks where alcohol reduced, the weeks where sleep suffered, the correlation between a stressful fortnight and a stalled scale. That self-knowledge is part of what the lifestyle component of treatment is designed to build. For a closer look at how other patients have experienced and recorded that journey, the Mounjaro diaries section brings together real-world accounts that put the numbers in context. If you are considering starting treatment and want to understand what the assessment process involves, our guide to Mounjaro in primary care explains how prescribing decisions are made. For broader context on weight-loss treatment options, the treatment overview page is a useful starting point.

Some people find published formats helpful, a structured Mounjaro weight-loss diary template can take the guesswork out of what to record. Others prefer a simple notebook. The format matters far less than the consistency. Ready to begin? Start your free consultation with our prescribers.