Starting Mounjaro weight loss treatment requires properly preparing the injection pen before use. This preparation process, called “priming,” makes sure the pen works correctly and delivers the correct dose of Mounjaro medication.
Many patients find this step confusing at first, but the steps below explain exactly how to prime a Mounjaro pen correctly, with practical tips to help you use Mounjaro for weight loss safely and effectively.
Priming a Mounjaro pen removes air bubbles and fills the needle with medication before your actual injection. This step means you’ll get the full prescribed dose when you inject Mounjaro.
Without priming, your first injection might deliver less medication than needed, as part of the dose would be used just to fill the needle space. The pen is working correctly when you see a drop of medicine at the tip of the pen after priming.
Priming also helps check that the pen is functioning properly before use, which prevents dosing errors and avoids wasting medication. This is especially important for your first injection with each new pen.
Prime the Mounjaro pen each time you prepare for an injection and every time you attach a new needle to it. Since you should always use a new needle for each injection, this means priming before every dose, including all four doses contained in a single pre-filled pen.
This important step ensures the needle is filled with medication and removes any air bubbles before each injection, helping you receive the full prescribed dose every time you inject.
When you’re priming a Mounjaro pen, you only need a very small amount of medication – just enough to see a drop at the needle tip. This typically means turning the dose knob to the prime position (a small dot or line) on the dose selector and pressing the injection button.
Don’t worry about wasting medication – the pen contains 4 doses and is designed with this priming step in mind. There’s enough Mounjaro solution inside to allow for priming while still delivering all four full doses. Using more than recommended for priming could result in not having enough medication for your final dose.
Always refer to the patient information leaflet before administering a new medication.
Start by washing your hands thoroughly with soap and warm water, or you can also use an antibacterial hand sanitiser, then dry them completely with a clean towel. This simple step helps reduce the risk of infection at the injection site by removing dirt and bacteria from your hands before handling the pen and needle.
Remove the Mounjaro Kwikpen from the fridge and inspect it carefully. Make sure the liquid inside is clear, colourless, and free from particles. If you notice air bubbles at the top of the cartridge, gently tap the cartridge holder to collect air bubbles at the top – this is normal.
Check the expiry date printed on the pen label, and never use a pen that is expired, damaged, or contains cloudy or discoloured solution. For a more comfortable injection, let the pen warm up to room temperature for about 30 minutes before using it.
Pull off the grey pen cap from your Mounjaro pen. There’s no need to twist it – a straight pull will do. Set the cap aside on a clean surface, as you’ll need to put it back on after your injection.
Take a new pen needle and remove the paper tab from the outer needle shield. With the pen held upright, push the capped needle straight onto the pen and twist until it’s secure. Don’t overtighten.
Then remove the outer needle shield and keep it for later – you’ll need it to remove the needle after your injection safely. Next, pull off the inner needle shield and throw it away in your household bin.
Hold your pen with the needle pointing up and away from your face and others. Turn the dose knob in either direction until the prime position lines up with the pointer (two clicks). Push the dose knob until it stops to release some medicine into the air.
With your thumb, firmly press the injection button all the way in until it stops, then slowly count to 5 while holding the dose knob. You should see a drop of medication appear at the needle tip – this confirms your pen is primed and ready to use. If you don’t see a drop, repeat this step up to 4 times until a drop appears.
If you think your pen is jammed, use our Mounjaro Jammed Pen Guide.
After successful priming, turn the dose knob until you hear a click and the dose indicator shows your prescribed dose. Each Mounjaro pen is pre-filled with the same dose for all four weekly injections (either 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg, depending on your prescription).
The pen will automatically stop when turned to the correct dose amount. Double-check that the dose shown in the dose window displays the proper dose before you inject the medicine. If you need to redial the dose, you can turn the dose knob in either direction until the correct amount is displayed.
You need to choose your injection site carefully. Select an area on your body for the injection. We recommend injection sites like your stomach (abdomen, staying 2 inches away from your belly button), thigh, or upper arm.
Clean the chosen spot with an alcohol swab and let it dry completely before injecting. Rotate injection sites each week to reduce the risk of infection, and don’t inject in the same area or inject into areas that are bruised, scarred, or tender. Choose a different spot each time you inject to vary the location each time you inject.
Gently pinch a fold of skin at the cleaned injection site. Insert the needle straight into your skin at a 90-degree angle to administer the injection. Press the injection button all the way in with your thumb until it stops.
Continue holding the dose button while you count to 5 to ensure you get the full dose. The dose indicator should return to “0” when the full dose has been delivered. Some patients prefer to count to 5 while holding the dose knob pressed in for extra assurance.
If the needle comes out before you finish the injection, you may need to reinsert the needle and finish the injection with any remaining medication.
After injecting, carefully place the outer needle shield back over the needle (don’t use your fingers to push it on). Twist the covered needle counterclockwise to remove the needle from the pen.
Dispose of the used needle in a sharps bin. Never reuse needles or store the pen with a needle attached, as this can lead to contamination, infection, or inaccurate dosing.
Place the pen cap back on the Mounjaro pen. Store the pen in the refrigerator between 36°F and 46°F (2°C to 8°C) until your next dose. Never freeze Mounjaro pens. If you’re travelling while using weight loss medications, you can keep the pen at room temperature (below 86°F or 30°C) for up to 21 days. Protect the pen from direct sunlight and keep it out of reach of children.
Remember to rotate the injection site each time to prevent skin irritatio when you take your weekly dose.
After your fourth and final dose, you might notice some liquid still left in the Mounjaro pen. This is completely normal and by design.
Each pen contains a small amount of extra medication to make sure you can properly prime the pen before each injection and still receive four full doses. This leftover medication is sometimes called ‘the golden dose’, but it isn’t enough for another complete Mounjaro dose and shouldn’t be used.
Once you’ve taken your dose four times, dispose of the pen according to your local guidelines for medical waste.
Managing your Mounjaro treatment shouldn’t be complicated. At Click2Pharmacy, we specialise in simplifying the entire process, whether you’re just starting treatment or looking to switch from your current provider.
Enjoy the convenience of home delivery, competitive pricing, and expert guidance on proper pen usage and injection instructions.
Ready for a better pharmacy experience? Visit our weight loss clinic today to learn how we can help with your Mounjaro prescription and ensure you know how to use the Mounjaro pen correctly.
The Mounjaro KwikPen must be primed each time you prepare for an injection. This means priming before every weekly dose, including all four doses in a single pen. Always prime after attaching a new needle and before selecting your dose to ensure proper medication delivery.
If no medicine appears at the needle tip during priming, try again up to 4 times. Hold the pen with the needle pointing up, and firmly press the injection button until it stops. If no drop appears after 4 attempts, change to a new needle and try priming again. If problems persist, contact your GP or pharmacy for assistance.
Using a Mounjaro pen without priming it first isn’t recommended. Skipping the priming step means you might receive less than your full dose because part of the medication would be used to fill the needle space. This could affect your treatment results and potentially waste medication in the long run.
Small air bubbles in the pen are normal and won’t affect your dose. The priming process helps remove air by pushing the dose knob and eliminates air from the needle pathway before injection. Don’t use the pen if you notice unusually large bubbles or if the medication doesn’t look clear. Contact your pharmacy instead of attempting to remove large air bubbles yourself.
Never reuse needles for priming or injecting Mounjaro. Each needle should only be used once and properly disposed of in a sharps container. Reusing needles increases the risk of infection, can damage the needle tip, causing pain, and may lead to medication contamination or inaccurate dosing.
You can attempt to prime a Mounjaro pen up to 4 times if you don’t see medication at the needle tip on your first try. If a drop doesn’t appear after 4 attempts, try replacing the needle with a new one and priming again. If you still experience problems after changing the needle, don’t use the pen and contact your pharmacy for a replacement.
