How to take Mounjaro
About this page. Written by the GLPInfo editorial team with AI assistance from the official sources listed at the end, and approved by the site owner before publication. It has not been reviewed by a named clinician. Published 27 Aug 2026 · last updated 27 Aug 2026 · next scheduled review 27 Nov 2026.
This page is information, not medical advice. It never tells you which medicine, dose or format is right for you: those decisions sit with you and a qualified prescriber. Spotted an error? Tell us and we'll fix it fast.
Everything here summarises the patient information leaflet and your provider's instructions, which always take precedence. Report suspected side effects through the MHRA Yellow Card scheme.
The routine
Mounjaro is injected once a week, on the same day each week, at any time of day, with or without food. The KwikPen holds four weekly doses. Injections go under the skin of the stomach area, thigh or upper arm, and the leaflet advises rotating sites rather than reusing the same spot. Your provider shows you the technique before your first dose; the leaflet's step-by-step instructions are the reference after that.
If you miss a dose
The leaflet's rule: if a weekly dose is missed, take it as soon as possible within four days (96 hours) of the scheduled time, then carry on as normal. If more than four days have passed, skip the missed dose and take the next one on the usual day. Never take two doses within three days of each other, and never double up. If several doses have been missed, ask your prescriber before restarting: after a break, treatment sometimes needs to resume at a lower step.
Storage
Unused pens live in the fridge at 2-8°C, never frozen. The pen in use can be kept below 30°C for up to 30 days, per the leaflet. Do not leave pens in cars, on windowsills or anywhere they may overheat, and check the leaflet's rules before travelling: travelling with GLP-1 medicines.
Sharps
Needles go in a sharps bin, never household waste. UK providers typically supply or sell sharps bins, and your local council or pharmacy explains disposal in your area.
Related: what is Mounjaro? · dose schedule · side effects · price comparison
Frequently asked questions
Can I change the time or day I take Mounjaro?
Yes, within the leaflet's rules: the injection day can move as long as the minimum gap between doses is respected. Your prescriber can confirm what fits your schedule.
What if I take too much Mounjaro?
Contact your prescriber or NHS 111 promptly, and 999 if you feel seriously unwell. Do not wait to see how it goes: too much of a GLP-1 medicine can cause severe nausea, vomiting and dehydration.
Where do I find the official instructions?
The patient information leaflet in the pack, also published on the electronic medicines compendium (linked below), is the authoritative instruction set. This page summarises it and never replaces it.