How to Inject Mounjaro and Wegovy: A Step-by-Step Guide

Quick Answer

To inject Mounjaro KwikPen, attach a new compatible needle, prime the pen, turn the dose knob until it stops at “1”, and inject under the skin of the abdomen, thigh or back of the upper arm. Press the knob fully, count slowly to five, check that “0” appears, then remove and safely dispose of the needle. Use Mounjaro once weekly as prescribed and rotate the exact injection spot.

Wegovy FlexTouch uses different flow-check and six-second holding steps, so follow the instructions supplied with your specific pen.

2–8°C fridge temperature for storing both pen types before first use

30 days maximum time after first use for Mounjaro KwikPen, stored at no more than 30°C

6 weeks in-use storage period for Wegovy FlexTouch, below 30°C or refrigerated at 2–8°C

Content last updated: 2 October 2026

It is normal to feel nervous before your first injection. This guide explains how to use Mounjaro KwikPen and Wegovy FlexTouch, including preparation, injection sites, the different steps for each pen, storage and safe needle disposal. Check which pen you have and read the Instructions for Use supplied in your pack before injecting. If anything is unclear, ask your pharmacist to talk you through it.

If you are still comparing the medicines, read more about the Mounjaro weight loss injection and Wegovy weight loss injection before starting treatment.

Which Pen Do You Have?

Check the name on your pen and packaging before you start. The comparison below covers Mounjaro KwikPen and Wegovy FlexTouch. Both use a separate needle, but their preparation and dose-selection steps differ.

Feature	Mounjaro KwikPen	Wegovy FlexTouch
Needle	Attach a new compatible pen needle for every injection.	Attach a new compatible pen needle for every injection.
Pen contents	Four fixed doses at the strength shown on the pen label.	Four doses at the strength shown on the pen label.
Preparation check	Prime the pen before every injection.	Check the flow before the first injection with each new pen.
Dose selection	Turn the dose knob to the full-dose position shown in the Instructions for Use.	Turn the dose selector until the dose counter shows your prescribed dose.
Injection	Press and hold the dose knob, following the KwikPen holding and completion checks.	Press and hold the dose button, following the FlexTouch holding and completion checks.

Check your exact pen before following the steps

If your packaging names a different device, such as a single-use Wegovy pen, follow the instructions supplied with that device. Do not apply FlexTouch or KwikPen steps to another pen type. If you are unsure which pen you have, ask your pharmacist before injecting.

Before You Start: A Simple Preparation Checklist

Read your pen instructions: keep the Instructions for Use nearby, particularly for your first injection or when starting a different pen type.
Wash your hands: use soap and water, then dry them before handling your supplies.
Check the label and expiry date: make sure you have the correct medicine and pen strength for your prescription.
Inspect the medicine: Mounjaro should be clear and colourless to slightly yellow. Wegovy should be clear and colourless. Do not use either medicine if it is cloudy, contains particles or looks different from the description in its leaflet.
Check the pen and its storage: do not use a frozen or damaged pen. If it has been dropped, follow the checks in its Instructions for Use and ask your pharmacist if you are unsure whether it is safe to use.
Gather your supplies: have your pen, a new compatible needle, alcohol wipes, clean cotton wool or gauze, and a sharps container within reach.

Choosing and Rotating Your Injection Site

Mounjaro and Wegovy are injected under the skin, into the fatty layer rather than a muscle or vein. Choose an area you can reach comfortably and follow the site diagram in your pen leaflet.

Stomach (abdomen): choose a spot at least 5 cm away from your belly button.
Thigh: use the front of the upper thigh. Sitting down may make this area easier to reach.
Upper arm: arrange for someone else to give the injection. For Mounjaro, use the back of the upper arm as shown in the KwikPen instructions.

Change the exact injection spot each week, including for your second dose. You can use the same general body area again, but choose a different point within it. You do not need to switch between your stomach, thighs and arms on a fixed schedule.

Avoid skin that is bruised, tender, red, swollen, hard or scarred, and follow any additional site restrictions in your leaflet.
Clean the chosen spot with an alcohol wipe and let it dry before injecting.
Keep a simple note of where you injected if this helps you avoid repeatedly using the same spot.

Mild redness or bruising can happen after an injection. If you use Wegovy, our Wegovy side effects guide explains common injection-site reactions and when to ask for medical advice.

How to Inject Mounjaro KwikPen

Complete the preparation checklist and choose your injection site before starting. Use these steps alongside the illustrated Instructions for Use in your pack.

Attach the needle. Remove the pen cap, swab the red inner seal and screw on a fresh needle. Keep the outer needle shield; discard the inner shield.
Prime before every injection. Turn the knob two clicks to the priming mark. Point the needle upwards and gently tap the cartridge. Press the knob fully and hold while slowly counting to five. Check for zero in the window and medicine at the tip. Prime into the air, not your skin. If no medicine appears, follow the leaflet's priming checks before continuing.
Select the full dose. Turn the knob until it stops at “1”. This means one full dose of your pen's strength, not 1 mg.
Inject and check. Insert the needle into your prepared site. Press the knob fully and keep holding while slowly counting to five. Check for “0” before removing the needle.

How to Inject Wegovy FlexTouch

These steps apply to FlexTouch. If your pack contains a different Wegovy device, use its own instructions.

Fit a fresh needle. Remove the pen cap and attach the needle securely. Remove both needle caps, keeping the outer one.
Check flow with each new pen. Before its first injection, select the flow-check symbol. Point the needle upwards and hold the button until zero appears. Look for a drop. If absent, follow the leaflet's flow-check procedure before injecting.
Select your prescribed dose. Turn the selector until the counter shows it. Do not count clicks to measure a dose.
Inject. Insert the needle, keeping the counter visible. Hold the button until zero appears, then continue pressing with the needle in your skin while slowly counting to six. Withdraw the needle.

After Either Injection

If there is a little blood, gently press clean cotton wool or gauze against the skin without rubbing. Use the retained outer needle cap to remove the needle, following your pen's illustrated instructions. Never replace the small inner cap. Put the used needle in a sharps container and replace the pen cap. Store your pen without a needle attached.

Pen Safety and Uncertain Dose Delivery

Never share your pen, even with a new needle. Do not withdraw medicine from a Mounjaro KwikPen into a syringe or try to obtain an extra dose from leftover liquid.

If you are unsure how much medicine was delivered, do not dial another full dose or guess a top-up. Follow your pen's Instructions for Use and contact your pharmacist for advice. For Mounjaro leakage, a stuck pen or an unexpected dose-window reading, see Mounjaro pen troubleshooting.

Storage and Handling

When	Mounjaro KwikPen	Wegovy FlexTouch
Before first use	Refrigerate at 2–8°C. Never freeze.	Refrigerate at 2–8°C, away from the cooling element. Never freeze.
After first use	Store at no more than 30°C for up to 30 days.	Keep for up to six weeks below 30°C or refrigerated at 2–8°C.
When to discard	After four doses or 30 days from first use, whichever comes first.	After four doses or six weeks from first use, whichever comes first.

Note the date you first use each pen. Keep the cap on, protect it from heat and light, and keep pens and needles out of children's sight and reach. Never use medicine that has been frozen, and always observe the expiry date. Our Mounjaro storage and expiry guide explains the 30-day in-use limit and what to check if storage conditions change. The Wegovy storage guide explains the six-week in-use limit for Wegovy FlexTouch pens.

When travelling, a suitable insulated pouch can help protect your medicine, but avoid direct contact with ice packs. If a pen has been left in a hot car or you are concerned about its temperature during delivery, contact your pharmacist before using it. For airport, hand-luggage and missed-dose planning, see our guide to travelling with Mounjaro or Wegovy.

Disposing of Needles Safely

Have a proper sharps bin ready before injecting. Used needles must never go loose into household rubbish, recycling or a public litter bin.

Put each used needle into your sharps bin immediately after removing it from the pen as directed in your pen instructions.
Keep the bin upright, out of children's reach, and follow its instructions for closing the lid between uses.
Do not fill it above the marked line. Seal it as instructed when it reaches that level.
Ask your local council about sharps collection, or ask your pharmacy or GP practice which local service accepts your bin. Check before taking it anywhere, as collection arrangements vary.

If you do not have a sharps bin, contact your pharmacy to arrange one and ask for advice on safe disposal. For empty pens with the needle removed, read our guide on how to dispose of Wegovy pens, then follow the disposal instructions in your medicine leaflet and your local service's guidance. Ask your pharmacist how to dispose of pens containing unused medicine.

What If You Miss a Dose?

Missed-dose instructions differ between Mounjaro and Wegovy. Check the guidance for your own medicine rather than applying one treatment's timing rules to the other. Never take a double dose to make up for a missed dose.

Mounjaro: see our guide to what happens if you miss a Mounjaro dose for the timing rules and advice after a treatment break. The Mounjaro dose schedule also explains how the weekly injection day can be changed safely.
Wegovy: see our Wegovy dose schedule and missed-dose advice for the timing rules. Contact your prescribing team if you have missed several doses or are unsure how to restart.

A missed dose is different from an injection where you are unsure how much medicine was delivered. For uncertain delivery, follow the pen-safety advice above and speak to your pharmacist before taking additional medicine.

Frequently Asked Questions

Does the Mounjaro or Wegovy injection hurt?

You may feel a brief sting or some discomfort. Take your time, relax the injection area and allow cleaned skin to dry before injecting. If you are nervous about your first dose, ask your pharmacist to explain the steps. Seek advice if pain is severe or persists.

Can I inject in the same spot every week?

Choose a different injection point each week. You can use the same general area, such as your abdomen, but avoid the exact spot used previously. Follow the injection-site guidance for your pen.

What if I see a bit of blood after injecting?

A small spot of blood can occur. Gently press clean cotton wool or gauze against the area without rubbing. Seek medical advice if bleeding is heavy or does not stop.

Can someone else give me the injection?

Yes, provided they understand how to use your specific pen. For a Mounjaro injection into the back of the upper arm, another person should administer it. Ask your pharmacist for guidance if either of you is unsure.

What should I do if my pen looks cloudy or has particles in it?

Do not use it. Mounjaro should be clear and colourless to slightly yellow; Wegovy should be clear and colourless. Contact your pharmacist if the medicine contains particles or its appearance differs from the leaflet's description.

Can I keep my pen at room temperature after first use?

Mounjaro KwikPen can be kept at no more than 30°C for up to 30 days after first use. Wegovy FlexTouch can be kept below 30°C or refrigerated at 2–8°C for up to six weeks. For the device-specific rules, read our Wegovy storage instructions. Discard either pen once its four doses are used or its in-use time limit is reached, whichever comes first. Never freeze either medicine.

Is it safe to travel with my pen?

Plan how you will maintain the storage conditions for your pen throughout the journey. An insulated pouch may help, but does not guarantee a safe temperature. Avoid direct contact with ice packs and do not leave your medicine in a hot car. Ask your pharmacist if you are unsure about storage during travel.

What happens if I accidentally inject too much?

Contact your prescriber or NHS 111 immediately for advice, even if you feel well. Tell them which medicine you used, how much you think you injected and when. Call 999 for severe symptoms such as difficulty breathing or collapse.

Do I need a new needle for every injection?

Yes. Mounjaro KwikPen and Wegovy FlexTouch require a fresh compatible needle each time. Ask your pharmacy which needles are suitable and check that you have enough before your next scheduled dose.

What should I do if I do not have a sharps bin?

Contact your pharmacy to arrange a proper sharps bin and get advice about any used needles you already have. Do not put loose needles in household rubbish or recycling. Ask your council or pharmacy about local collection arrangements.

Never Injected Before? We're Here to Help.

Happy Pharmacy's pharmacy team can help you understand your pen instructions and prepare for your first injection. If you are considering treatment, start an online consultation to find out whether it is suitable for you.

Start Your Free Online Consultation → Use code SWITCH10 if you're switching from another provider
Happy Pharmacy is a GPhC-registered pharmacy (No. 9013192) — Superintendent Pharmacist: Palvinder Deol

Your cart is currently empty.