How to Use the Mounjaro KwikPen

The Mounjaro KwikPen is a multi-dose pre-filled pen that delivers four fixed weekly doses of tirzepatide. To use it, you check the pen, attach a new needle, prime the pen (two clicks, then press until the window shows zero), dial a full dose (turn until it stops at "1"), inject under the skin of your stomach or thigh, hold the dose knob down while counting slowly to five, and then remove and safely dispose of the needle. You prime before every injection, use a new needle each time, rotate injection sites weekly and keep unused pens in the fridge. Always follow the Instructions for Use in your pack and the advice of your pharmacist or prescriber.

This guide explains each step in plain English, with tips on technique, storage, disposal and common problems. It is based on the UK Instructions for Use and Eli Lilly's UK medical information. For the bigger picture on treatment, see our complete guide to Mounjaro in the UK or the Mounjaro hub.

Getting to know your KwikPen

The Mounjaro KwikPen became available in the UK in early 2024, and the MHRA was the first major regulator to authorise this multi-dose presentation of tirzepatide.

Key features:

• One strength per pen. Pens come in 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg strengths. Always check the label matches your prescribed dose.
• Four doses per pen. Each pen delivers four fixed doses, one each week.
• Dose knob and window. You turn the knob to prime and to set a dose, and the window shows the setting.
• Fixed doses. The pen is designed to give a full dose each time; it does not support split or partial doses.
• Single-patient use. Never share a pen with anyone, even with a new needle, because of the risk of passing on infections.

What you need

• your Mounjaro KwikPen at the correct strength
• a new, compatible pen needle (not included in the pack)
• an alcohol wipe or soap and water (optional, for cleaning the skin)
• a sharps bin for the used needle
• a cotton wool ball or gauze (optional)

Step-by-step: preparing and injecting

These steps summarise the UK Instructions for Use and Lilly's UK guidance. Always refer to the leaflet in your pack, which takes precedence, and ask your pharmacist or prescriber to show you if you are unsure.

Stage 1: prepare

1. Wash your hands with soap and water.
2. Check the pen label. Confirm it is Mounjaro, at your prescribed strength, and not past its expiry date.
3. Check the medicine. Look through the window: the liquid should be clear and colourless to slightly yellow. Do not use it if it is cloudy, discoloured or has particles in it.
4. Check the pen is undamaged. Do not use a pen that has been dropped and looks damaged, or that has been frozen.
5. Choose and clean your injection site (see below). If you clean it, let the skin dry.

Stage 2: attach a new needle

6. Remove the pen cap.
7. Wipe the rubber seal at the end of the pen with an alcohol wipe, if your instructions advise it.
8. Attach a new needle. Remove the paper tab, push the needle straight onto the pen and screw it on until tight. Remove the outer needle cap and keep it for later; remove and discard the inner needle cap.

Stage 3: prime the pen (every time)

Priming removes air and checks the pen and needle are working.

9. Turn the dose knob until you hear two clicks. The window will show an extended line, which is the priming setting.
10. Hold the pen with the needle pointing up and tap the cartridge gently so any air bubbles rise to the top.
11. Push the dose knob in until it stops, then count slowly to five while holding it. The window should show "0". You may see a drop of medicine at the needle tip.

If you do not see the window return to "0", or you are unsure whether priming worked, follow the troubleshooting steps in your Instructions for Use or contact your pharmacist before injecting.

Stage 4: set your dose

12. Turn the dose knob until it stops and "1" shows in the window. This represents one full dose.

Stage 5: inject

13. Insert the needle into your skin at the chosen site, as shown in your instructions.
14. Push the dose knob in until it stops, then keep holding it and count slowly to five. The window should show "0".
15. Remove the needle from your skin. If a small drop of blood appears, press lightly with cotton wool or gauze. Do not rub.

Stage 6: after the injection

16. Carefully replace the outer needle cap, unscrew the needle and place it straight into a sharps bin. Do not store the pen with a needle attached.
17. Replace the pen cap and store the pen as described below.
18. Make a note of the date and how many doses you have used, so you know when the pen is finished.

Before your first injection: a checklist

Starting a new injectable medicine can feel daunting. Before your first dose, check that you:

• have been shown how to use the pen, either in person or by a video demonstration from your provider
• have the patient information leaflet and Instructions for Use to hand
• have compatible pen needles and a sharps bin
• know which strength you have been prescribed and that it matches the pen label
• know your planned injection day and how you will remember it
• know who to contact if you have a problem or a side effect

If anything is unclear, ask your pharmacist. Pharmacists can usually talk you through the steps, and some will demonstrate using a training pen.

Injecting for someone else

Carers and family members sometimes give injections, for example if the person has limited dexterity or poor eyesight. If you are giving the injection:

• wash your hands and follow the same steps, including priming
• you can use the back of the upper arm as well as the stomach and thigh
• take care to avoid needlestick injuries by recapping the needle carefully with the outer cap only and disposing of it straight away
• keep a record of the date and dose to avoid accidental double dosing

Choosing and rotating injection sites

Mounjaro is injected subcutaneously, into the fatty layer just under the skin. Recommended sites are:

• Stomach area (abdomen): at least 5cm (about two inches) from the belly button
• Front of the thigh
• Back of the upper arm: only if someone else is giving the injection, as it is hard to reach yourself

Tips for comfort and skin health:

• Rotate each week. Use a different spot each time, even if you stay within the same body area.
• Avoid problem skin. Do not inject into skin that is tender, bruised, red, scaly, hard, scarred or has stretch marks.
• Keep a simple pattern. Some people move clockwise around the stomach, or alternate between left and right thighs.

Rotating sites helps reduce injection-site reactions and lumps under the skin (lipohypertrophy), which can affect how well the medicine is absorbed.

How many doses are left?

Each pen gives four doses. After the fourth, there will be a small amount of medicine left in the cartridge because the pen holds extra for priming. This is normal. Do not try to use the leftover medicine or to get an extra dose from the pen. Using leftover medicine risks an inaccurate dose and contamination.

Discard the pen after:

• four doses, or
• 30 days after first use, even if doses remain, or
• if it has expired, been frozen or is damaged.

Storing the KwikPen

• Before first use: store in the fridge at 2°C to 8°C, in the original carton to protect it from light. Do not freeze, and do not use a pen that has been frozen.
• After first use: Lilly's UK guidance says the pen can be stored at room temperature up to 30°C, away from direct heat and light, and must be discarded 30 days after first use.
• Keep out of the sight and reach of children.

Your Instructions for Use may also describe limited circumstances in which an unused pen can be kept outside the fridge. Check the leaflet rather than relying on general advice. For travel, see storing and travelling with Mounjaro.

Needles and sharps disposal

• Use a new needle every time. Reused needles can become blunt, blocked or contaminated.
• Needles are not supplied in the pack. Your pharmacy or provider should supply compatible pen needles; ask which type to use.
• Use a sharps bin. Place used needles straight into an approved sharps container.
• Disposal arrangements vary. In many areas, councils collect full sharps bins, and some pharmacies accept them. Check with your local council, GP practice or pharmacy.

Never put loose needles in household rubbish or recycling.

Common problems and what to do

Frequently made mistakes

Most problems with pen injections come from a few common slips:

• Skipping priming after the first dose. The UK instructions say to prime before every injection.
• Not turning the dose knob fully to "1", which may mean a full dose is not set.
• Removing the needle too quickly, before the slow count of five has finished.
• Reusing needles, which can lead to blocked needles, pain and infection.
• Leaving the needle attached between doses, which can let air in or medicine leak out.
• Injecting into the same spot every week, which can cause lumps under the skin.
• Using the wrong strength after a dose change, because pens look similar.

A quick mental checklist each week (label, liquid, new needle, prime, dial, inject, count, dispose) helps avoid these.

Making injections more comfortable

Many people find the injection less daunting than expected because pen needles are very fine and short. Some practical tips that people commonly find helpful:

• Choose a time each week when you are relaxed and not rushed.
• Make sure the skin is dry if you have cleaned it with alcohol, as wet alcohol can sting.
• Insert the needle in one smooth movement.
• Keep the needle in place for the full count of five.
• Use a new needle each time, as fresh needles are sharper.

If you have a fear of needles, tell your prescriber or pharmacist. They can talk you through the process, and some providers offer video demonstrations.

Choosing your injection day

Inject on the same day each week, at any time of day, with or without food. If you need to change your injection day, the UK product information allows this as long as there are at least three days (72 hours) between two doses. If you miss a dose, see Missed a Mounjaro dose?.

Moving between strengths

When your prescriber increases or decreases your dose, you will receive a pen of a different strength. Points to remember:

• Check the label carefully each time, particularly in the weeks after a dose change.
• Finish or discard pens as instructed. Do not combine doses from different pens.
• Expect side effects to flare a little after an increase; see our Mounjaro side effects guide.

See Mounjaro doses explained for the full titration schedule.

Spotting genuine pens

Fake weight-loss injections have been seized in the UK. A genuine Mounjaro KwikPen is only supplied on prescription by a registered pharmacy. Warning signs of a fake or unlicensed product include vials or powders, unusual packaging, pens from social media sellers or beauty salons, and no consultation. See Fake and unlicensed weight loss jabs.

Regulated providers should offer clear injection training, written instructions and a way to contact a pharmacist with questions. Our providers page compares these service features, and our prices page explains whether needles and sharps bins are typically included.

When to speak to a professional

Ask your pharmacist or prescriber for a demonstration before your first injection if you have not been shown how to use the pen. Contact them if:

• you are unsure whether you received a full dose
• you think you have injected too much
• injection-site reactions are spreading, painful or not settling
• you have repeated problems priming or injecting with the pen
• your pen has been frozen, damaged or stored incorrectly

Seek urgent medical help (NHS 111, or 999 in an emergency) if you have:

• swelling of the face, lips, tongue or throat, difficulty breathing or a widespread rash after injecting
• severe, persistent abdominal pain, which may spread to your back, with or without vomiting
• signs of infection at an injection site, such as spreading redness, heat and swelling with fever
• vomiting that will not stop or signs of severe dehydration