How to inject Mounjaro safely

Mounjaro is injected under the skin once a week, you inject it yourself into the stomach area, the top of the thigh, or the back of the upper arm. These areas are called injection sites.

Mounjaro helps with weight loss by making you feel fuller and less hungry. This can help you eat less over time. Each pen contains 4 doses, and you use 1 dose every week on the same day.

If you're considering treatment, you can find full details on how Mounjaro works, pricing, and eligibility on our Mounjaro injections page.

The best Mounjaro injection sites are your abdomen, thigh, or the back of your upper arm. Mounjaro is a subcutaneous injection, which means it should be injected into the fatty tissues just beneath the skin. We recommend the abdomen or thigh for this reason.

Whatever injection site you use, divide it up into 4 sections and choose a new site every week, including switching between the left and right side of your body. You can also switch between injection sites, such as using your abdomen one week and your upper legs the next.

Pros and cons of each Mounjaro injection site

A study on the 5mg maintenance dose found that injecting into the abdomen led to the highest concentration of tirzepatide in the bloodstream. However, the study also found that more people reported side effects when injecting in the abdomen.

This Mounjaro injection site pros and cons table compares each injection site to help you choose the best place for you:

How often should I rotate injection sites?

You should rotate injection sites every week. If you find that an area works best for you, such as the abdomen, there’s no need to change to a different area of the body, only the part of the skin that you inject.

Break the injection site into 4 smaller areas and use a different section every week. If it helps you to remember, write down which section you injected into each week. Make sure there’s always a finger width distance between where you injected last week and where you inject this week.

Not rotating your injection site can increase the risk of injection site reactions or pain.

1. Clean your hands with soap and water.

2. Remove the pen from any outer packaging and check the expiration date, dose, and that there’s no sign of damage. The liquid should not be cloudy, discoloured, or have floating particles (except air bubbles, which can be removed in the priming stage).

3. Wipe the red inner seal with a swab.

4. Attach a new needle to the pen by pushing the needle on and twisting it tight, keeping the outer cap on to avoid injury. Make sure the needle is sealed and undamaged.

5. Choose your injection site. Clean it with a sterile wipe or soap and water if you have not already.

6. Remove the outer needle cap and put it safely beside you for after the injection. Remove the inner needle shield and throw it away. Turn the dose knob at the bottom of the pen until you hear 2 clicks. This puts the pen in priming mode.

7. Prime the pen by holding it with the needle pointing up. Tap the cartridge gently if you can see any air bubbles that need to come to the surface. Press down on the dose knob until it stops, hold it down and count to 5 slowly. A small amount of medicine should come out – do not inject this dose into your body.

8. Adjust the dose knob to ‘1’.

9. Insert the needle into your skin, keeping the dose counter visible and avoiding any veins or muscles. You do not need to pinch your skin to do this.

10. Press down on the dose knob and count slowly to 5. You should see the dose count move to ‘0’. There’s also a small click when the dose has been injected.

11. Remove the needle from your skin and place the outer cap back on so you can dispose of it safely in a sharps bin.

12. Replace the pen cap and store it back in the refrigerator, or a safe place away from sunlight and children. Remove the needle before storage.

What dose of Mounjaro do I inject?

Always check your dose against your dosage plan and prescription if you’ve ordered several doses at once. You must follow the dosage plan, or you could put yourself at risk of serious or more severe side effects.

When you first start taking Mounjaro, your dose will be increased slowly from 2.5mg to a maximum maintenance dose of 15mg. You can also stay on lower doses of 5mg or 10mg if you’re happy with how your treatment is going, or if you get side effects on a higher dose.

➤ Find out more about the standard Mounjaro dosage plan.

Bring it to room temperature

If you store Mounjaro in the refrigerator, bring it to room temperature for around 30 to 60 minutes before injecting it. This can make it less painful compared to injecting it straight from the fridge due to the temperature of the liquid.

Use an ice pack or cold compress

Apply an ice pack for around 15 minutes before you inject Mounjaro. This will numb the area to make it less painful. Use a cold compress again after injecting to reduce soreness or swelling.

Find the best injection site for you

You can use the same site the whole time you inject Mounjaro as long as you’re using a different area of skin each time. As long as they’ve read all the information, you can get someone to give you the injection in any of the sites we’ve mentioned, not just your upper arms.

Use over-the-counter medications

Take an over-the-counter painkiller like ibuprofen or paracetamol before you take the injection. This gives it time to kick in and help with any pain or discomfort. If you still have mild pain for a few hours or days after the injection, you can continue using painkillers to help.

You could also try an over-the-counter numbing cream to apply before injecting Mounjaro. This can also help if you’re nervous about the injection.

Reducing anxiety around injections

If you have anxiety with needles or injections, make sure you do it in a private and comfortable environment, lie down, and have someone help or support you. If you find it difficult to relax your body, this could make the injection more painful.

Try a distraction technique, such as talking about something you like with the person helping or supporting you, or a breathing exercise to help you relax. Speak to your doctor if you’re finding injections very stressful because of your anxiety.

There is no best time to inject Mounjaro, but it should be given at the same time and day every week. We recommend that you choose a suitable time and day that works around your schedule.

Consistency is most important when taking Mounjaro. By injecting Mounjaro at the same time and day each week, the concentration of tirzepatide in your body will remain steady – this can improve its effectiveness and reduce side effects.

You can inject Mounjaro before, after, or with food. If you get certain side effects like nausea or stomach pain, it may be best to eat a meal around an hour before injecting it. If you’re injecting with help from someone else, make sure this schedule also works for them.

There are a few things to look for that will tell you whether you’ve injected Mounjaro correctly:

1. When you watch the dose counter, it should turn from ‘1’ to ‘0’.
2. The pen will click when the dose has been injected, but this is a small click and may not be heard in a loud environment.
3. There should be no significant leakage from the injection site. It should not feel wet, but it’s normal if there’s a very small amount of medicine on the needle tip when you take it out.
4. You should not feel severe pain when injecting Mounjaro. It may feel like a sharp sting, but this should start improving within a few seconds to a few minutes. If you have severe pain that is not going away after the injection, or you have any other severe reactions like a widespread rash that does not go away, or difficulty breathing, you should call 999 or go to A&E.

As you continue taking Mounjaro, you’ll start to know what it feels like when the needle is in your skin and when the injection is done.

It’s important to monitor any reactions when injecting Mounjaro and speak to your doctor if they are ongoing or severe.

Do not choose an injection site that has sore, broken, or irritated skin.

Common reactions

A common Mounjaro side effect that may affect 1 in 10 people is an injection site reaction, such as the site getting:

• itchy
• red
• sore
• swollen

This might happen when you first start using the injection, or if you forget to switch injection sites every week. These reactions are usually mild and temporary, but speak with your doctor if this happens after every injection, even after switching areas of the skin and injection sites. They might recommend taking an antihistamine when you inject Mounjaro.

Uncommon reactions

An uncommon Mounjaro side effect that may affect up to 1 in 100 people is injection site pain. While it’s normal to feel slight pain, stinging, or discomfort, it’s not normal for it to be very painful to inject Mounjaro.

If you find the injection site painful despite trying different areas, and this cannot be managed by a cold compress and over-the-counter pain medication, speak to your doctor straight away.

After injecting Mounjaro, it’s normal to have a small mark, a bit of redness, or slight swelling at the injection site. Most of the time, this goes away on its own after a short while.

Here is what you can do next:

• if there is a small drop of blood, gently wipe it away with a clean tissue
• use a plaster if needed, especially if the area is sore or bleeding
• if the site feels itchy, you can take an antihistamine
• if there is mild pain, you can take a painkiller like paracetamol to ease any discomfort

Try not to press or rub the area after injecting. If you notice a rash that spreads, ongoing pain, or signs of infection (like warmth or swelling that gets worse), speak to your doctor.

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