Mounjaro Pen Not Turning to 1: Causes and What to Do (October 2026)

01 · The core answer

Why your Mounjaro pen won't turn to 1

Your Mounjaro pen is most likely not turning because there is no longer a full dose inside it.

Each KwikPen contains four weekly doses.¹ So the first question is a simple count: how many injections have you taken from this pen? Check your injection diary, your calendar, or the week-by-week pen timeline we publish.

If you have taken four weekly doses from the pen, the dial stopping is expected. You do not need to fix anything. You need your next pen.

If you are confident you have taken fewer, there are only a few realistic explanations: a miscount, a pen that was previously used for an extra injection, or a genuine fault.

02 · Your next move

What to do next, depending on your situation

What you should do depends on whether you have used all four weekly doses.

03 · Keeping on schedule

Getting your next pen without losing your routine

If your pen is finished or faulty, the priority is getting a replacement pen in time for your usual injection day. Our Mounjaro pen page shows every dose; the 2.5mg pen is £169.99, and repeat orders are £25 off the standard price. Every order goes through a short consultation reviewed by a GPhC-registered prescriber, so allow for that when you plan.

If you are not sure which strength you should order next, your prescriber guides that. The wider picture is on our weight loss clinic page.

04 · How the dial works

How the KwikPen dial works

You turn the dose knob until the dose indicator shows the correct dose in the window.

That matters when something feels off. Some people expect a fixed number of clicks and worry when the sound or feel differs. The window is what counts. If it shows your full dose, the pen holds at least that much. If it will not reach your dose, the pen is telling you it cannot deliver one.

The pen also limits itself. This is a safety feature, designed to stop you drawing up more than the pen holds. It is the reason the dial can feel stuck on a finished pen.

The pen is the same design across strengths. Mounjaro comes in 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg KwikPens, and each holds four weekly doses of that strength.¹ A stuck dial therefore means the same thing at any strength: check your count first.

05 · Counting your doses

Counting your doses and the liquid left inside

You can have liquid left in the pen and still have no full dose available. The honest answer is that the amount you see through the pen is not a reliable guide to what you can inject.

The dose window is the guide. Residual liquid does not change that, and you should not try to use it as an extra injection or combine it with another pen.

Why not? Taking more or smaller portions than the pen is designed to deliver is not licensed and is not supported by the pen's design. Altering doses outside the licence means unknown dosing accuracy and no safety data.¹

A practical way to avoid doubt is to keep a record. Mark each injection date on a calendar, or log it in the free GLPTrackr companion app, which tracks a GLP-1 journey on iOS and Android. When a pen stops turning, you can see at a glance whether the count adds up.

If a pen looks nearly empty and you still believe you have an injection left, do not guess. Contact the pharmacy that dispensed it and describe what the window shows.

06 · A stuck dial mid-course

When the dial is jammed before the pen is finished

If you are sure you have not used all four weekly doses and the dial will not turn, treat the pen as possibly faulty and stop. We have a dedicated guide on how to unjam a Mounjaro pen, and a companion page on a pen that will not twist.

Do not force the knob. Do not try to take the pen apart. Do not inject a smaller dose than the window shows.

Check the patient information leaflet that came with your pen, then contact the pharmacy. Keep the pen, the box and the label; they help the pharmacy investigate.

If a pen is faulty, you may also report it. The MHRA Yellow Card scheme accepts reports about medicines and their devices, and a report helps the regulator spot patterns.¹⁹ Reporting does not replace getting a working pen; do both.

If the pen is not pushing down when you inject, rather than not turning, that is a different symptom with its own guide: Mounjaro pen not pushing down.

07 · Priming and locking myths

Priming, locking and other common questions

Follow the pen's own instructions in the patient information leaflet, and ask your pharmacy if the leaflet and your pen seem to differ.¹³ Our guide to preparing a Mounjaro pen covers the steps before an injection.

The dial stopping on a finished pen is not a lock you can release; it is the pen reaching the limit of the medicine inside. If the dial has stopped on a finished pen, the answer is a new pen, not a workaround.

If you are unsure what a normal used-up pen looks like, ask the pharmacy that dispensed it. They can look at the pen with you, or at a photo, and tell you whether it behaves as expected.

08 · Missed day when pen ends

If the pen runs out on your injection day

A finished pen on injection day should not mean a missed dose, but if it does, follow the missed-dose rule. If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day.¹ If more than 4 days have passed, skip the missed dose entirely and take the next one on your normal day — never take two doses within 3 days of each other.¹

So a stuck dial is not an emergency, but a delay in sorting a replacement can turn into one. Contact your pharmacy the same day you notice the problem.

You can also change your injection day if that helps you fit around delivery. You can change your weekly injection day if needed, as long as at least 3 days (72 hours) have passed since your last dose.¹ Do this deliberately, not by accident, and keep the new day consistent afterwards.

There is no "best" time of day to inject. Mounjaro works the same morning or evening, with or without food. What matters is the same day each week.¹ Many people choose a weekend morning so early side effects fall on days off, but that is a convenience, not a requirement.

If you have taken a very long break because you could not get a pen, speak to your prescriber before restarting. Do not assume you can resume at your previous strength.

09 · Storage and damage

Storage, cold damage and a pen that behaves oddly

Poor storage is a reasonable thing to check when a pen misbehaves. Keep Mounjaro pens in a fridge at 2–8°C and never freeze them.¹ Never use a pen that has been frozen.¹ A pen left at the back of the fridge against a cold wall, in a cool bag next to ice, or in a hold luggage compartment is at risk.

Once in use, a pen can be kept out of the fridge not above 30°C for up to 30 days, after which it should be discarded.¹ Keep the pen cap on to protect it from light.

If you travel, carry pens in hand luggage rather than hold luggage, which can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription.¹ For unopened pens, store them in the fridge; they keep until the expiry date printed on the box. If an unopened pen has been out of the fridge, check with the pharmacy before using it rather than relying on a remembered day limit — figures circulating online often come from other countries' labels.¹

None of this explains a dial that stops on a pen you have barely used, but a pen with suspected storage damage is a pen to set aside and ask about. When a pen has any doubt attached to it, the safer choice is always to ask first and inject later. For the wider problem, see our overview of a Mounjaro pen not working.

10 · Last dose problems

Trouble with the last dose in a pen

Trouble tends to appear at the end of a pen, because that is where the amount left matters. If the final injection seems incomplete, or the dial will not reach your dose, the pen may simply have too little medicine for a full dose.

Our page on the last dose of a Mounjaro pen not working goes through that situation in detail.

If you did inject and are unsure whether the whole dose went in, do not repeat the injection to compensate. Make a note of the date and what happened, and contact your pharmacy or prescriber. They can advise on when to take the next dose.

Keep the pen until you have had an answer. It is useful evidence if the pharmacy needs to look into it, and it stops you accidentally reusing it.

11 · Selling or sharing pens

Unused pens: selling and sharing

You should not sell or give away spare Mounjaro, because it is a prescription-only medicine supplied to the person it was prescribed for after an online consultation reviewed by a GPhC-registered prescriber. Do not sell unused pens: the medicine was assessed for you, at your dose, and stored in the conditions you kept it.

The same goes for sharing. A pen is designed for one person's weekly dose, and passing it between people raises obvious safety and hygiene problems. We explain this on our sharing a Mounjaro pen page.

If you have pens you no longer need, ask your pharmacy how to dispose of them safely. Sharps and pens should not go in ordinary household rubbish. Our orders include a sharps bin and injection guidance for exactly this reason.

If you have stopped treatment, nothing needs doing while the medicine clears. Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4–5 weeks to clear the system.¹

12 · Who to contact

Who to contact and what to say

Contact the pharmacy that dispensed your pen first, and give them clear details. If your pen came from us, email support@everydaymeds.co.uk or use the chat in your account portal; our support team is available on weekdays during office hours. Our pharmacy is GPhC-registered (9012878), and our prescribing team provides ongoing monthly reviews, dose-titration and side-effect support.

To get the quickest answer, tell them the strength of the pen, how many injections you have taken, what the dose window shows, and whether the pen has been stored away from the fridge or frozen. A photo of the window helps.

Repeat orders re-check suitability, and nothing ships automatically, so a replacement still needs a brief review by a prescriber. Same-day dispatch applies when ordered by 3pm, and delivery is free, next-day and tracked, in temperature-controlled packaging. Do not leave it until the day you need to inject.

Mounjaro (tirzepatide) is a prescription-only medicine, used alongside a reduced-calorie diet and increased physical activity. Individual results vary. This is information, not a substitute for medical advice.