Does the new Mounjaro KwikPen have less medicine left over?
Yes. Lilly’s UK medical site says the modified Mounjaro (tirzepatide) KwikPen leaves less medicine after the fourth dose, because of an added part behind the plunger. It still gives 4 fixed weekly doses of 0.6 mL, used the same way. The Australian leaflet says to throw the pen away after 4 doses and never inject the leftover.
- Mounjaro is a prescription-only medicine in Australia. Your prescriber decides your dose and pen strength.
- The facts come from the Australian Product Information (PI), the Consumer Medicine Information (CMI) leaflet and the Instructions for Use in the carton.
- We don’t publish medicine prices for Australia.
What changed in the new KwikPen?
Lilly’s UK medical site says a part was added behind the plunger of the modified KwikPen, so less medicine is left after 4 doses.5
That site is written for UK health professionals. It says both pens work the same way and have identical instruction steps. Both hold enough for priming before each injection plus 4 doses of 0.6 mL. In the UK, it says, old and new pens are supplied side by side until the old stock runs out.5
We found no Australian notice from Lilly or the TGA about the change. Australia’s medicines information site does list two instruction leaflets, ‘KP 1.0’ from August 2025 and ‘KP 2.0’ from January 2026. The steps match. KP 2.0 adds one new line. If the pen won’t turn to a full dose, throw it away with the medicine still in it.3,4
How can I tell if my pen is the new one?
Look at the plunger. In an unused modified pen it sits further down the cartridge. After the fourth dose it ends near the bottom.5
Lilly’s UK site says the added part causes the lower plunger. It also says the two pens work the same way.5 The Australian instructions say to read the leaflet each time you get a new pen. There may be new information. They also say not to use a pen that is expired or looks damaged.3
How many doses are in a Mounjaro KwikPen?
Four. Each Australian KwikPen delivers four 0.6 mL doses, one a week, in six strengths from 2.5 mg to 15 mg.1
The leaflet gives a starting dose of 2.5 mg for 4 weeks, then 5 mg. Your doctor may raise the dose by 2.5 mg every 4 weeks, to 15 mg at most.2 Pen needles aren’t in the pack, and you use a new one each time.1,3
The leaflet says some medicine is left after the 4 doses, and that this is normal. The pen stops you dialling a full dose after the fourth one. “Do not inject the leftover medicine.”2 The instructions add that you shouldn’t move Mounjaro from the pen into a syringe. Throw the pen away 30 days after first use, even with medicine left.3 Our answer on keeping Mounjaro out of the fridge covers storage.
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What do the clicks on the dose knob mean?
The knob has two settings in the instructions: the prime position before each injection, and the full 0.6 mL dose.3
To prime, you turn the knob until you hear 2 clicks, then push a little medicine into the air. For the injection, you turn the knob until it stops at the dose icon. That icon equals a full 0.6 mL dose.3
The instructions warn that not turning the knob fully to the icon gives less than your prescribed dose.3 The Australian label also warns of underdosing unless the knob is turned to the ‘1’ icon.1 The leaflet says not to change your dose unless your doctor tells you to.2 Guide 6 explains how pens and prescriptions work in Australia.
What do Australians on Mounjaro report about the new KwikPen?
From public patient forums: 9 Reddit threads in r/MounjaroAus, r/mounjaroaustralia and r/GLP1Australia, read in October 2026. Personal reports, not medical evidence.
What people describe
- Matches the leaflet Several explain that the pen was only ever meant to give 4 doses. The Australian leaflet says each KwikPen holds 4 fixed doses, and that some medicine left after them is normal.2
- Not studied Several say newer pens have a black part above the plunger and little or no liquid left at the end. We found no Australian source describing the new pen’s look.
- Not studied In one thread, people say pharmacy staff didn’t know the pen had changed. People report this; we found no source on it.
- Label says otherwise Several describe using an opened pen for months. The instructions say to throw it away 30 days after first use.3
Advice people share
- Not studied Several suggest checking the expiry date or batch on the box to guess which version it is. We found no Australian source that lists them, and a few found the batch rule unreliable.
- Matches the label A few say pen needles come separately and to use a new one every time. The label says none come in the pack, and the instructions say to use a new needle for each injection.1,3
- Label says otherwise Most threads discuss counting clicks to take a lower dose from a stronger pen. The Australian leaflet says each pen contains 4 fixed doses, and the instructions say to turn the knob until it stops at the full-dose icon. The leaflet also says not to change your dose unless your doctor has told you to.1,2,3
- Label says otherwise Many describe drawing out the leftover with a syringe. The instructions say not to move Mounjaro from the pen into a syringe, and the leaflet says not to inject the leftover.2,3
- difficult or noisy breathing6
- a swollen tongue, or swelling or tightness in the throat6
- persistent dizziness or collapse6
Think you injected too much? The Mounjaro leaflet says to get urgent medical attention, even without symptoms. Phone the Poisons Information Centre on 13 11 26, contact your doctor, or go to the nearest emergency department.2
For advice any time, call healthdirect on 1800 022 222.7
Read the full picture
Related questions
Sources
- Eli Lilly. Mounjaro and Mounjaro KwikPen (tirzepatide) Australian Product Information, vA14.0, date of revision 2 Oct 2026, sections 2, 4.2, 6.4 and 6.5. Australian label. medsinfo.com.au (PDF)
- Eli Lilly. Mounjaro KwikPen (tirzepatide) Consumer Medicine Information, prepared September 2026, section 4. Australian leaflet. medsinfo.com.au (PDF)
- Eli Lilly. Instructions for Use, Mounjaro KwikPen, ‘Mounjaro KP 2.0 IFU (AU)’, revised January 2026: important information, steps 2 to 10, storing and troubleshooting. Australian leaflet. medsinfo.com.au (PDF)
- Eli Lilly. Instructions for Use, Mounjaro KwikPen, ‘Mounjaro KP 1.0 IFU (AU)’, revised August 2025. Australian leaflet. medsinfo.com.au (PDF); both leaflets listed on medsinfo.com.au
- Lilly Medical Information (UK, for UK healthcare professionals). Modified Mounjaro (tirzepatide) KwikPen design, date of last review 14 Oct 2025. UK source: we found no Australian equivalent. medical.lilly.com
- healthdirect. Anaphylaxis (last reviewed November 2024). healthdirect.gov.au
- Healthdirect Australia. How healthdirect can help you (“call triple zero (000) for an ambulance immediately”; nurse helpline 1800 022 222). healthdirect.gov.au
Last checked 25 Oct 2026 · Next review due 25 Oct 2027 · Report an error
How this answer was made. Written by the GLP Guidebook team from the sources above, all checked on 25 Oct 2026. The ‘What people report’ section summarises public patient forum posts we read; it is not medical evidence, and we never pass on advice that goes against the label. We don’t publish medicine prices, and we don’t name, rank or link to sellers or telehealth services. It’s general information, not medical advice, and nothing here is an offer to supply any medicine. Talk to a GP, pharmacist or other qualified prescriber before starting, stopping or changing any medicine. How we write