How to Inject Mounjaro? Step-by-Step Guide

Injecting Mounjaro involves attaching a needle to your KwikPen, priming the pen to remove air bubbles, setting it to your prescribed dose, and disposing of the needle after each use.

Designed for adults prescribed Mounjaro for type 2 diabetes or weight management, this guide walks you through the step-by-step injection process.

Learn how to choose an injection site, prepare your pen, inject it correctly, and dispose of sharps safely.

Before You Start: What You'll Need

Mounjaro is easy to inject thanks to the KwikPen. Here's what you'll need:

1. The Mounjaro Pen: Make sure you're using the right pen, as they all look the same. However, the KwikPen should clearly list the dosage.
2. New Needles: The needles are sold separately from the pen, and you should use a new pen needle for each dose. If you're not sure which ones to buy, your prescriber can offer advice.
3. Alcohol Wipes and Containers: Use alcohol wipes to clean the skin and the pen's seal. Place used needles in special containers.

Note: Please store Mounjaro in the fridge at 2°C–8°C when you're not using it. Once the pen is in use, you can keep it at room temperature for up to 30 days. We recommend taking the pen out of the fridge 15- 30 minutes before injecting it, as it can make the experience more comfortable.

Where to Inject Mounjaro?

There are three areas where you can inject Mounjaro: the abdomen, upper arm, and upper thigh. All have benefits, so it's really a matter of personal preference.

When injecting into the abdomen, focus on the fatty area (5 cm below the belly button). The same thing applies if you're using the upper thigh as an injection site. Focus on the outer and upper thigh instead of injecting Mounjaro into the inner thigh.

If you have someone to help you, you can inject Mounjaro into your upper arm, but it's a challenging injection site for one person.

Rotating sites each week can reduce skin irritation, but if you choose to stay in the same area each week, make sure you leave a finger's width between the previous and new injection spots.

Do Different Injection Sites Impact Results?

Surprisingly, some studies do suggest that different injection sites might define your results and reactions. For example, one clinical study found that injecting Mounjaro into the thigh or upper arm tends to have fewer side effects than injecting it into the upper arm (NIH).

Clinical trials also showed that appetite reduction was stronger when injecting Mounjaro into the stomach (24%) compared to the arm (13%).

However, there are no significant differences in weight loss.

How to Inject Mounjaro?

The following steps are based on official Eli Lilly KwikPen instructions. If you'd rather watch the video, you can view it here.

1. Wash Your Hands: Wash your hands with soap and water, then dry them before touching the needle or pen.
2. Remove the Pen: If the pen is stored in your fridge, remove it for at least 15 minutes (30 is best) to ensure it can reach room temperature. Under no circumstances should you heat the pen.
3. Check the Pen: Make sure the pen matches the prescription strength and that the liquid is clear or slightly yellow. Never use a damaged pen. If everything's OK, you can remove the cap.
4. Wipe the Seal: Use an alcohol swab to wipe the red inner seal at the top of the pen. Let it dry.
5. Attach the Needle: Use a compatible needle and remove the paper tab. Push the needle into the pen and turn it clockwise until it's secure. Remove the outer shield and set it aside, then remove the inner shield and place it in the bin. Never use the same needle twice, as it can increase the risk of infections.
6. Prime the Pen: Priming the pen removes air bubbles. Hold the pen with the needle pointing upward, and turn the dose knob until it makes two clicking sounds. Tap the cartridge holder gently, then count to 5 while pushing the dose knob in. This is part of the priming process and has nothing to do with your weekly dose.
7. Set Your Mounjaro Dose: If there's no liquid in the needle tip after you've primed, please check your information leaflet or contact the prescriber. If everything's OK, you can turn to your prescribed dose, which will show in the window.
8. Prepare the Site: Once you've chosen your injection site, clean the skin with an alcohol wipe.
9. Inject Mounjaro: Pinch a fold of skin to ensure a Mounjaro subcutaneous injection, and hold your KwikPen at a 90-degree angle. Insert the needle into your skin and press the dose button down. The pen will click when the dose begins and again when it's complete (usually around 10 seconds).
10. Bleeding: Some people may experience a small amount of bleeding, which is completely normal. Just use a cotton pad or gauze to gently press the affected area.
11. Disposal: Grab your outer needle shield and place it over the needle, being careful to protect your fingers. Then remove the needle and place it in the container. Replace the pen cap and keep your pen at room temperature.

How to Dispose of Needles Safely?

Used needles should always go in a designated sharps container, as they're classed as clinical waste. Once you've completed your Mounjaro injection dose, avoid putting the needle in your household rubbish or recycling bins, as it can be a health hazard for anyone who handles waste.

Many pharmacies, GP surgeries, and local councils offer free sharps bins, and some also provide collection services. You can use the bin until it's full, then seal it for collection.

Always use the outer needle shield when removing the needle from your pen, as it protects your hands.

How Do I Know If the Dose Was Delivered Successfully?

After administering your dose, hold it for a full 10 seconds after the second click to ensure your skin absorbs the medication. It's normal for a small amount of liquid to appear, and the best way to check whether it was delivered successfully is by looking at the dose window reading.

If it says 0, that confirms you've received the full dose. Once you reach the end of a pen, you won't be able to turn it anymore. That's because each pen has four doses; after it's complete, you'll move on to a new pen.

If you're unsure whether your doses are being administered correctly, please ask your prescriber for advice.

Common Problems and How to Fix Them

Most people find that Mounjaro is relatively easy to inject in the abdomen, thighs, or upper arm. However, you might encounter some issues along the way. These include:

I didn't hear two clicks while priming — what now?

In most cases, you can fix this by ensuring the needle is attached securely and you're holding the pen upright. But if you fix these things and priming still isn't working, contact your pharmacist or prescriber.

The dose knob won't turn to my dose

If you haven't completed the priming process, do so now. However, if the knob still won't move, contact your pharmacist.

I removed the pen before the 10 seconds were up. Did I get the full dose?

Possibly not. Self-injecting medication can take some getting used to, but you shouldn't inject Mounjaro a second time to make up for the potentially lower dose. Check with your pharmacist or prescriber for advice.

There's an air bubble in the pen — is it safe to inject?

Small bubbles are normal and harmless. Priming pushes air to the top of your cartridge and enables you to clear it before injecting. If you notice large bubbles, repeat the priming process.

My injection site is red and itchy

Injection site reactions are common when you begin treatment, with 1 in 10 people experiencing redness, itching and minor swelling. You can reduce discomfort by rotating injection sites, but severe pain, inflammation and itching mean you should contact a doctor immediately.

My pen looks different from the diagram

This is completely normal. In April 2026, the manufacturer released an updated KwikPen version, so yours might look different from the one in your patient information leaflet. Regardless of the pen, the injection steps are the same.

I accidentally skipped the priming step and injected without priming — what do I do?

If you heard both clicks, the dose window reached 0, and you held it the full 10 seconds, then the dose was probably successful. Priming clears air from your needle and doesn't affect your dose. If you're unsure, your pharmacist can offer support.

Tips for Reducing Injection Pain and Anxiety:

• Make sure you give the pen time to reach room temperature before injecting it. Cold medication will sting more.
• Dry your skin after cleaning it with an alcohol swab, as damp skin can be more uncomfortable.
• Relax
• Make sure your skin is completely dry after cleaning it; injecting into damp skin is more uncomfortable
• Relax your muscles at the injection site. Tensing up can cause more pain.
• Count slowly to 10 while holding, instead of rushing.
• Rotating injection sites weekly avoids reactions and complications. However, if you notice one site is more comfortable, rotate to that exact spot. Always avoid injecting Mounjaro within a two-inch circle around your belly button.
• Some people find that having some music on, looking away, or practising breathing exercises can reduce discomfort. Remember, the first time can be daunting, but once you learn the proper techniques and find an injection site that works for you, things will get easier.
• If you have a phobia of needles, your prescriber may offer nurse-led sessions for first-timers.