Consumer guide
How to Switch Pharmacy on Mounjaro Without Missing a Dose
Moving your Mounjaro (tirzepatide) prescription from one UK pharmacy to another is allowed, common and usually takes less than a week. This guide gives you the steps in order, what to have ready, how to time it so you never run out, and what the new pharmacy will ask. It applies equally to Wegovy.
Key facts
- You can switch at any point in treatment, provided you have not signed up to a multi-month contract. You are not tied to the pharmacy that started you, and you do not need its permission.
- Every pharmacy must run its own consultation before prescribing. Under GPhC guidance updated on 4 February 2025 that includes independently verifying your weight, height and BMI, and two-way communication with the prescriber, so a switch always involves a new assessment.
- Most pharmacies will let you move up a dose if you want to, or continue you at your current dose, if you can show evidence of it: photos of your pen box with the dispensing label, plus order screenshots from your current provider.
- It is recommended you start the switch while you still have at least one dose in hand. It normally takes a few days, and most pharmacy operations close over the weekend. A missed weekly dose can be taken up to four days late; beyond that it is skipped, and a longer gap often means restarting at a lower dose.
- New-customer discount codes usually apply to switchers too, because you are a new customer to that pharmacy. Compare the first-order and ongoing price before you choose.
How to switch, step by step
- Check your pen. Note your current dose (2.5, 5, 7.5, 10, 12.5 or 15 mg), your injection day, and how many doses you have left. Do not start the switch on the day your last pen runs out.
- Gather your evidence. Take a clear photo of your pen box showing the dispensing label with your name, the dose and the date. Save screenshots of your order confirmations from your current pharmacy. A formal treatment summary is not usually needed; the label and the orders are what prescribers ask for.
- Pick the new pharmacy on total price, not the headline. Use the discount price list for your dose. It shows the checkout total including delivery and consumables where charged, and it flags maintenance-friendly and restart-friendly providers. Check the new pharmacy’s maintenance BMI policy at the same time, in the maintenance directory.
- Complete the new consultation as an existing patient. Say you are already on treatment and give your current dose. Upload the pen photo or summary when asked. Expect to verify weight and height by video, by a dated photo on scales with ID, or from your GP record; a questionnaire alone is no longer enough.
- Ask for your current dose to be continued, or to move up. A prescriber can start you at the same dose, or step you up if you are due and want to, when your last injection was recent and your evidence is clear. If there has been a gap, expect a conversation about restarting lower.
- Order with a code, then wait for approval before cancelling anything. Tap a code on the pharmacy’s Monj page to copy it, paste it at checkout, and check the total. Do not cancel your old subscription until the new prescription is approved and dispatched.
- Cancel the old pharmacy in writing. Stop the subscription from your account or by email, ask for confirmation, and keep it. Check whether a cycle has already been charged for a pen not yet dispatched, and ask for a refund if so.
- Take your next dose on the usual day. The pen from the new pharmacy is the same medicine. Inject on your normal day at your normal dose unless the new prescriber has told you otherwise.
What to have ready
| Item | Why the new pharmacy wants it | Where to get it |
|---|---|---|
| Pen box photo with dispensing label | Proves you are on treatment, at what dose, and when it was last supplied | Your current box; photograph before you dispose of it |
| Order screenshots | Show dates, doses and that supply was regular; pair them with the box photos | Your email or pharmacy account |
| Treatment summary (optional) | Not usually needed; useful only if you have lost boxes and order history | Your current pharmacy’s support team |
| Current weight and height, verifiable | Required under GPhC guidance since February 2025 | Video call, dated photo on scales with ID, or GP record |
| Weight-related condition evidence, if your BMI is 27 to 29.9 | Needed to meet the licence criteria at that BMI | GP letter, repeat prescription or test result |
| Photo ID | Identity check for a prescription-only medicine | Passport or driving licence |
Timing it so you do not miss a dose
Mounjaro is injected once a week. The product information says a missed dose can be taken up to four days (96 hours) late; after that it should be skipped and the next dose taken on the usual day. It also allows you to move your injection day, as long as there are at least three days (72 hours) between doses. Those two rules give you a small buffer, not a large one.
Practical timing: start the new consultation when you have a dose left, or before. Most pharmacies approve and dispatch within one to three working days, next-day tracked delivery is standard, and most pharmacy operations close over the weekend, so a week is ample and leaves room for a query. If you are down to your last dose, start today and use the four-day window if the new pen is a day or two late. Never take two doses to catch up, and never bridge a gap with a pen from an unregulated seller; the risks are covered in our GPhC verification guide.
If you have already had a gap. Prescribers commonly restart at a lower dose after a break of more than a couple of weeks, judged against the timeline your supply history shows, because tolerability is built up by stepping the dose. That is a clinical decision for the new prescriber, not a pharmacy rule. Our restarting Mounjaro guide explains what to expect. If you have stockpiled pens and the gap is only on paper, be ready to upload order screenshots and photos of the labels on your pen boxes together, so the prescriber can see that supply matched your dosing.
Eligibility when you switch
The licence criteria are the same everywhere: a BMI of 30 or more, or 27 or more with a weight-related condition, with NICE’s lower thresholds for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds. The BMI requirements guide sets them out. What differs between pharmacies is how they treat someone already on treatment whose BMI has fallen below the starting threshold.
Smaller independent pharmacies generally accept existing patients on evidence of treatment and continue them below the starting BMI. Some larger providers apply the starting threshold to switchers as if they were new, which means a person who has done well may be refused. Before you pay for a consultation, check the pharmacy’s stated maintenance BMI in the maintenance directory; if it is not listed, ask, and get the answer in writing.
What it costs to switch
- The new pharmacy’s first-order code. You are a new customer to it, so first-order discounts normally apply. Check the ongoing price too, since the second month is what you will keep paying.
- The old pharmacy’s subscription. Cancel before the next billing date. A pen already dispensed on prescription usually cannot be returned; a cycle charged but not dispatched can be refunded if you ask. Our subscription pricing guide covers the rights involved.
- Consultation fees. Most online pharmacies fold the consultation into the pen price; a few charge separately. The Monj price list shows the checkout total, so a separate fee is already included.
- Delivery and consumables. Needles and sharps bins are included by some pharmacies and charged by others. Again, the checkout total in the table includes them where they are charged.
Why people switch, and what to check for each reason
| Reason | What to check before you move |
|---|---|
| Price has gone up | Compare the ongoing price at your next dose, not the introductory price at your current one |
| Stock problems | Look for pharmacies showing your dose in stock; ask about lead times before paying |
| Prescription stopped at a BMI or time limit | Choose a pharmacy with a stated maintenance policy that covers you; read what to do when a prescription is stopped |
| Poor communication | Send a pre-sales question and see how fast and how well it is answered |
| Want in-person collection | Some high-street chains offer collection; compare the price premium in the table |
Five mistakes to avoid
- Cancelling the old pharmacy first. Get the new prescription approved and dispatched before you stop the old one.
- Starting the switch with no doses left. The four-day window is a safety margin, not a plan.
- Throwing away the pen box. The dispensing label is your proof of dose; photograph it.
- Choosing on the first-order price alone. The ongoing price and the maintenance policy matter more after month one.
- Not telling your GP. A private prescription on your NHS record is safer than a secret one, and it helps if you ever need NHS support.
Common questions
Can I switch pharmacy while on Mounjaro?
Yes, at any point, unless you have signed up to a multi-month contract. You complete a new consultation with the new pharmacy, provide evidence of your current dose, and most will continue you at that dose. You do not need the old pharmacy’s permission.
Will the new pharmacy make me restart at 2.5 mg?
Not if your last dose was recent and you can show evidence of your current dose. After a gap of more than a couple of weeks, prescribers commonly restart lower to rebuild tolerability. That is a clinical decision for the new prescriber.
What evidence do I need to switch?
A photo of your pen box with the dispensing label and screenshots of your orders, plus verifiable weight and height and photo ID. A treatment summary is not usually needed.
How long does switching take?
Usually under a week: one to three working days for approval and next-day tracked delivery. Start when you have a dose left, or before; most pharmacy operations close over the weekend.
Can I use a new-customer discount code when I switch?
Usually yes, because you are a new customer to that pharmacy. Check the code’s terms, and compare the ongoing price as well as the first-order price.
What if I miss a dose during the switch?
The product information allows a missed dose to be taken up to four days late. After that, skip it and take the next dose on your usual day. Never double up.
Sources
- Medicines and Healthcare products Regulatory Agency, via the electronic medicines compendium. Mounjaro KwikPen: Summary of Product Characteristics, section 4.2 (missed doses and changing the injection day).
- General Pharmaceutical Council. Guidance for registered pharmacies providing pharmacy services at a distance, including on the internet, updated 4 February 2025.
- National Institute for Health and Care Excellence. Overweight and obesity management (NG246), January 2025.
Monj is an independent price information service operated by Medstack Ltd. It does not sell, prescribe or supply medicines and does not give medical advice. Dose decisions are for your prescriber. Report suspected side effects through the MHRA Yellow Card scheme.
