What to do before taking Mounjaro: a practical preparation guide

The decision your prescriber needs information to make

Starting Mounjaro is a clinical decision, not just a lifestyle one. Your prescriber is weighing up your BMI, any existing health conditions, the medicines you already take and a handful of contraindications before they approve treatment. That is why the preparation starts with giving them an accurate picture.

Be honest about every medicine you take, including supplements and herbal remedies. Tirzepatide slows gastric emptying, which affects how quickly other medicines are absorbed, something a prescriber needs to factor in, particularly if you take anything time-sensitive. It is also worth mentioning any history of pancreatitis, gallbladder problems, or thyroid conditions, since these influence whether Mounjaro is the right choice for you.

One misconception worth clearing up gently: some people assume that because Mounjaro is available through a private online pharmacy, the clinical assessment is more of a formality. It genuinely is not. At nume, a real clinician reads your answers and medical history before any decision is made. That review is the same whether you have been on treatment elsewhere for months or are completely new to GLP-1 medicines. You can read more about our clinical team and their approach if you would like to know who is doing the assessing.

The NHS medicines page for tirzepatide lists the main contraindications clearly and is worth reading before your consultation.

Contraception, HRT and other medicines to discuss first

This is probably the area most people have not thought about before their first consultation, and it matters. If you use the combined oral contraceptive pill, UK guidance recommends adding a non-oral method of contraception (condoms, for example) for the first four weeks of Mounjaro treatment and for four weeks after every dose increase. The reason is straightforward: slowed gastric emptying can reduce how reliably the pill is absorbed. There is no equivalent published concern for semaglutide, but for tirzepatide specifically this is documented guidance from NHS England.

If you are on HRT, NHS England also advises considering a transdermal form (patches or gels rather than tablets) for the same absorption reason. Talk to your GP about this before your first pen arrives, rather than after.

Pregnancy is a separate and firmer line. Mounjaro is not recommended during pregnancy, while breastfeeding, or if you are actively trying to conceive. Under-18s are outside the licensed age range entirely. These are not just cautions: they are the basis on which a prescriber will decline to approve treatment, and for good reason.

Questions about how these interactions play out day-to-day are covered in more detail on our guide to what to do while taking Mounjaro.

Practical things to sort before your pen arrives

Once your consultation is approved, your Mounjaro pen is dispatched the same day (for orders reviewed before noon, Monday to Friday) and arrives via tracked DPD delivery the next working day. Our page on what to do before starting Mounjaro covers a few things worth sorting in advance so you are ready.

First, make space in your fridge. Mounjaro is stored at 2–8°C and should not be left out beyond the window described in the Patient Information Leaflet, read that leaflet before you open the pen, not after. Keep it away from the freezer compartment and away from ice packs.

Second, tell your GP you are starting treatment. Our pharmacy notifies your GP as part of our standard process in line with GPhC guidance, but a direct conversation with your own doctor means they have context if you call them with a question later. It also means your prescription history stays joined up.

Third, think about injection technique before your first dose. You do not need to be an expert (the pen is pre-filled and the Patient Information Leaflet walks you through each step) but reading it in advance means your first injection is not the first time you have thought about it. Abdomen, thigh and upper arm are all suitable sites; rotation matters over time. Our guide to taking Mounjaro covers technique in plain terms.

If cost has been a factor in your thinking as you research treatment options, our Mounjaro cost page sets out what a legitimate private prescription actually includes and why the headline price is not always the whole story.

What 'being prepared' actually changes

Preparation does not guarantee an easy experience, some people find the first few weeks of tirzepatide bring noticeable nausea or digestive disruption, and that is a documented part of how the medicine works rather than a sign something is wrong. What preparation does is reduce the surprises: you know what to watch for, you know which symptoms warrant a call to your prescriber, and you know your contraception and other medicines are accounted for. If you are wondering about timing your injection, our guidance on whether you can take Mounjaro before bed is worth reading too.

The NHS England guidance on weight management injections covers the broader clinical context, including contraception and surgical considerations, and is worth a read before you start.

If you want to understand what to expect once treatment is underway, the before and after information on Mounjaro sets out what the clinical evidence says, honestly and without the overselling that is common in this space. And if you have questions our prescribers can answer, starting your free consultation is the right next step.