Written by: the Medetone Medical Team
Medically reviewed by: Dr Abdullah
Reading time: 5 minutes · Guidance verified: October 2026
You are on the fourth injection from your pen, and something looks off: the pen feels nearly empty, the plunger seems stiffer, and afterwards there is still liquid inside. Understandably, people worry they have missed part of their dose. How to get the last dose of Mounjaro out of the pen is a common question, and the short answer is reassuring. The fourth dose is delivered exactly like the first three, and the liquid you see afterwards is not a missed dose. This guide explains both points. Mounjaro is a prescription-only medicine and this article is informational. If you are starting treatment, the Mounjaro treatment page explains how the process works.
Quick answer
Doses per KwikPen: 4 fixed doses, one each week
The last dose: delivered the same way as every other
Leftover liquid: normal and expected, not a fifth dose
Discard after: 4 doses or 30 days from first use
Never: combine, transfer or extract medicine from pens
Your pen holds exactly four doses
A Mounjaro KwikPen contains four fixed doses, one injected each week, so a single pen covers roughly a month. The fourth injection is your last from that pen.
The pen is engineered to deliver a full, measured dose right up to the fourth injection. There is no reduction in what you receive on the final one. If you have been following the weekly schedule, your fourth dose is as complete as your first. Our titration guide sets out how strengths progress over the weeks.
How to get the last dose of Mounjaro: the technique
How to get the last dose of Mounjaro involves exactly the same sequence as every other injection. Nothing changes for the final one.
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Check the pen. Confirm it is in date, undamaged, and the liquid is clear and colourless to slightly yellow.
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Attach a new needle. A fresh needle every single time, including the last.
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Dial the dose. Turn the knob until it stops and "1" appears in the dose window. That is one full dose. Do not count clicks.
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Inject. Insert the needle, press the knob until it stops, and hold for a slow count of five.
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Confirm. Check that "0" is showing in the dose window before withdrawing.
That final check is the one that actually answers the worry behind this question. "0" in the dose window is your confirmation that the full dose was delivered, regardless of how much liquid remains visible in the cartridge. Our full injection guide covers each step in more detail.
If "0" does not appear, reinsert the needle at the same site and complete the injection. Do not redial the dose.
Why the plunger can feel different
Some people notice the pen requires slightly firmer, steadier pressure on the final dose. This is normal mechanics as the cartridge empties, not a sign of a faulty pen.
Press slowly and steadily rather than forcing it, hold for the full count, and let the dose window confirm completion. Letting the pen reach room temperature for about 30 minutes beforehand also makes the plunger move more smoothly, which helps on the last dose in particular. Our storage guide covers temperature handling.
The liquid left afterwards is not a dose
This is the part that causes most confusion, and it is worth stating plainly.
After the fourth dose, you will see medicine remaining in the pen. This is expected. Every pen is manufactured with a small amount of extra liquid so that all four doses can be delivered in full. That residue is overfill, not a fifth dose. It is not enough for a complete dose and the pen cannot measure or deliver it.
So when people ask how to get the last dose of Mounjaro out and mean that leftover liquid, the answer is that there is nothing to retrieve. You have already received all four doses. Discard the pen after the fourth injection or 30 days from first use, whichever comes first.
What you should never do
A few things are genuinely unsafe, and worth being direct about:
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Never try to extract the leftover medicine with a syringe or any other device. The residue cannot be measured accurately and the pen is not designed for it.
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Never transfer or combine medicine between pens. Each pen is a sealed single-patient device, and opening or tampering with it risks contamination and dosing errors.
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Never redial a dose if you are unsure one was delivered. Reinsert and finish instead.
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Never inject a second dose to compensate for one you think was incomplete, unless your prescriber tells you to.
If you are genuinely uncertain whether a dose was delivered, contact your prescriber or pharmacist rather than guessing. Taking extra is riskier than a single missed dose.
Discard after 4 doses or 30 days
Keeping track across pens
The simplest way to avoid uncertainty is to know where you are in the pen. Note the day you start each new pen and tick off each weekly injection, using a calendar or the dose-tracking chart included with the Instructions for Use.
That record does two things: it tells you when the fourth dose is due, so the pen running low is expected rather than alarming, and it gives your prescriber an accurate picture at your next review.
Frequently asked questions
How many doses are in a Mounjaro pen?
Four, taken one week apart. The pen is discarded after the fourth or after 30 days from first use.
Why is there still liquid after my last dose?
That is overfill, included so all four doses deliver in full. It is not an extra dose and cannot be used.
Can I get a fifth dose out of the pen?
No. The residue is not a measurable dose, and attempting to extract it is unsafe.
Why does the last dose feel harder to press?
Normal mechanics as the cartridge empties. Press steadily, hold for a slow count of five, and check the dose window.
How do I know my last dose went in?
"0" in the dose window confirms the full dose was delivered.
In summary
How to get the last dose of Mounjaro is the same as every dose before it: new needle, dial to "1", inject and hold, confirm "0". The KwikPen is designed to deliver four fixed weekly doses, and the liquid left afterwards is deliberate overfill rather than a missed dose. Discard the pen and move on to the next one with confidence that you received everything you were prescribed.
For clinical support, start an assessment with a licensed clinician or read more on the Mounjaro treatment page. Patients in the UK can access treatment through Medetone UK or our partner service Rightangled, and patients in the United States through Medetone US.
Medical information: this article is for information only and does not replace diagnosis, prescription or medical advice. Mounjaro is a prescription-only medicine. Always follow the Instructions for Use supplied with your pen.
References :
AIFA, Agenzia Italiana del Farmaco (Italy): https://www.aifa.gov.it
AEMPS, Agencia Española de Medicamentos y Productos Sanitarios (Spain): https://www.aemps.gob.es
ANSM, Agence nationale de sécurité du médicament (France): https://ansm.sante.fr
CBG-MEB, College ter Beoordeling van Geneesmiddelen (Netherlands): https://www.cbg-meb.nl
BfArM, Bundesinstitut für Arzneimittel und Medizinprodukte (Germany): https://www.bfarm.de
European Medicines Agency, Mounjaro EPAR: https://www.ema.europa.eu/en/medicines/human/EPAR/mounjaro
