Sometimes what changes on a prescription is the ingredient name rather than a familiar brand, and the first thing a reader notices is a word they have not been using. If yours has moved from semaglutide to tirzepatide, a prescriber decided that, and the reasons sit with them. GOV.UK is clear that these are prescription-only medicines to be used under professional supervision, which is another way of saying that the decision was never yours to make and is not yours to unpick. This page deals with a smaller and entirely practical question: what happens to the notes you keep.

Learn to label your own records by ingredient

Brand names and ingredient names describe the same thing at different resolutions, and a log that only ever names one of them becomes hard to read later. Semaglutide is the active substance behind Wegovy, Ozempic, and Rybelsus. It reaches people as an injection given once a week and as tablets taken by mouth, and official labelling now covers tablets under all three of those names rather than only the oldest of them. Tirzepatide is the active substance in Mounjaro and in Zepbound, both injections given weekly.

Writing both names in your record, once, at the point of change, saves an enormous amount of confusion. A note that says only the brand becomes ambiguous if the brand available to you changes with your country or your supply. A note that says only the ingredient loses the detail a pharmacist may need. FDA advises reviewing and updating a personal medication list whenever something changes, such as a new prescription, and a change of active substance is about as clear a change as there is.

Read route and timing off your own prescription

One trap worth naming: route and frequency belong to the specific pack, not to the ingredient and not even reliably to the brand. Semaglutide arrives both as an injection and as a tablet, and a brand name alone no longer settles which of those you were handed. Whatever you have been given, the instruction that applies is the one on your own prescription and in the leaflet inside your own pack, and it is the one to record.

So write down what you have actually been asked to do, in the words you were given, and date that entry. Do not carry forward the rhythm of your previous product on the assumption that it transfers. If any part of the instruction is unclear, a pharmacist can read the leaflet with you, which is a better use of an afternoon than working it out from a forum.

What in your log survives, and what resets

This is the useful distinction, and it is not obvious. Some of what you record is about your body and continues uninterrupted. Some of it is about your response to a particular medicine and starts over.

  • Weight, measurements and photographs continue. They were never about the medicine; they were about you, and the series stays valid across the change as long as you keep taking them the same way
  • Your general health notes continue. Sleep, mood, activity, other conditions, all of it runs on
  • Your side-effect history does not continue. It described how you responded to a different active substance and cannot be extended into the new stretch
  • Your appetite and fullness notes half-continue. The underlying observations are still meaningful, but any sense you had built of what is normal for you on treatment needs re-testing rather than assuming
  • Any personal rules of thumb about which days were difficult do not survive at all

In practice that means keeping your weight and measurement series unbroken while starting a fresh symptom record. Two different treatments of the same notebook, in the same notebook.

Symptom vocabulary has to be rebuilt

NHS guidance on semaglutide lists nausea, diarrhoea, constipation and stomach discomfort among the common effects, and MedlinePlus describes a broadly comparable set for tirzepatide. Because the lists overlap, it is tempting to assume the experience will too. That assumption is what makes an early symptom record thin and unhelpful.

Describe what you notice as though describing it for the first time. What it was, when it started relative to your last dose, how long it went on, what made it better or worse, and whether it stopped you doing something you had planned. MedlinePlus also notes that GLP-1 medicines affect appetite, fullness, and digestion generally, which is a reminder that early notes about eating are as valuable as notes about symptoms and are often the ones people skip.

Update the paperwork, not only the diary

A change of ingredient tends to leave a trail of small documents saying the old thing. Your medicines list, if you keep one, needs the new ingredient name on it. Any repeat prescription arrangement, any note held by another clinician who treats you for something unrelated, and any card or record you carry may all still name the previous medicine.

It is worth doing this in one sitting rather than piecemeal. Go through every place your treatment is written down, correct each one, and note the date you did it. The alternative is discovering the omission during an appointment about something else entirely, at which point you are reconstructing the change from memory in front of somebody who needed it to be accurate.

Bring the corrected list to your next appointment, whoever it is with. A clinician treating you for an unrelated problem may not have been told anything about the change, and an accurate list is the most reliable way that information travels.

What this page will not do

It will not tell you how one ingredient compares with the other in amount, strength, or effect, and it will not describe how a change between them is staged, because none of that is record-keeping and none of it is safe to read off a general page. Those questions have answers, and the person prescribing your treatment is where the answers live.

Get urgent medical help for severe abdominal pain, persistent vomiting, an inability to keep fluids down, or signs of a serious allergic reaction. A notebook is for patterns over weeks; it is not the right response to a symptom that is escalating in front of you.