How to inject Mounjaro?

Mounjaro is a fat-loss drug that is sweeping the nation. It is administered as a weekly injection that you use yourself or with the help of a friend. You have to administer the drug via a subcutaneous injection into either the stomach, thigh or upper arms (if you have the assistance of someone else). However, we recommend injecting into the stomach.  It may be daunting to try Mounjaro for the first time, so we’re here to help you through it.

Five key takeaways: How to inject Mounjaro

1. Mounjaro is a weekly injection for weight loss.
   You inject it just under your skin (in your stomach, thigh, or upper arm). Most people find the stomach easiest to use.
2. Rotate your injection site each week.
   Don’t inject in the same exact spot every time—move to a different area each week to avoid irritation or soreness.
3. Prepare and use your pen carefully.
   Always wash your hands, check the pen and medicine, and use a new needle each time. Follow the instructions step by step for a safe injection.
4. Mild skin reactions can happen, but are usually minor.
   You might notice redness, itching, or a small rash where you inject. This is normal and usually goes away. If you get a lot of swelling or pain, tell your doctor.
5. Take your time and use good technique to reduce pain.
   Inject slowly, clean the skin, and use an ice pack if needed. If you’re sore afterward, a cold compress or pain relief like paracetamol can help.

What is Mounjaro?

Mounjaro is a fat-loss drug that is trending right now; it is administered as a weekly injection and contains the active ingredient tirzepatide.

It works by sending signals to:

• the brain to suppress your appetite and make you feel fuller, and
• to the stomach to slow down emptying

leading to reduced food intake and weight loss [1].

Injection sites

When you inject Mounjaro, you need to choose an appropriate area to use as an injection site. The drug needs to be injected under your skin in either your stomach, thigh, or upper arm (this one might be tricky to do yourself, so you should only do this with some help from someone else).

Injection site rotation

You can stick to one area to inject each week, but you must change the injection site within the area each week.

For example, if you inject to the left of your belly button one week, you can inject on the right side the following week.

You can also switch up the injection site each week if you wish; for example, on the first week, you can inject your thigh, then on the second week, you can inject your stomach, and on the third, you can go to your other thigh. It is entirely up to you. Just find out what works for you.

Where to inject

• If you are self-injecting, pick an easy area for an injection site, such as your stomach or thigh. If you are getting help from a friend, you can be more creative and choose the upper arm, but it’s best practice to select an area with a bit of body fat.
• When you have picked an injection site, divide the area into four equal parts(look at the diagram below if you are confused). Work your way through each section so that, over four weeks, each area is injected only once.
• If you choose to inject your stomach, make sure the site is at least 5cm away from your belly button.
• Make sure that your injection site is at a minimum of one finger length away from the last.

Preparing for an injection

Before taking Mounjaro, some preparation is necessary. When you purchase Mounjaro from Courier Pharmacy, it is shipped with an ice pack via Royal Mail Tracked 24 and includes:

• The Mounjaro pen filled with a month’s supply of the medication,
• A patient information leaflet and an instruction leaflet on how to use the drug,
• Sharps bin,
• BD 4mm pen needles,
• Alcohol wipes.

Before using the drug for the first time, read the instruction leaflet and the patient information leaflet carefully.

Choose a day to inject Mounjaro each week

After you have read all the information and have a good understanding of how to take the drug, pick a day and time that you can commit to each week.

It is essential to choose a day and time you can be consistent with because this allows you to have the desired amount of the medication in your system. This keeps the drug working effectively and allows your body to get used to the drug, reducing the possibility of side effects.

Before you inject Mounjaro:

• Wash your hands thoroughly with soap and then dry them
• Make sure that the medicine is up-to-date and the dosage is correct
• Inspect the pen to make sure there is no damage to the pen
• Check that the liquid is clear, not frozen, or cloudy and does not contain any particles
• Remove the cap and have a fresh needle ready, check that the needle is sealed and not damaged or tampered with
• Wipe the rubber bung with an alcohol swab

How to inject

Now that you have washed your hands and completed all your safety checks, it’s time to inject yourself.

It doesn’t matter how big or strong you are. We are all scared of needles, and injecting yourself can seem like a daunting task, but if you follow these simple steps, the process will be a piece of cake, like the ones you are not eating because you are on a diet…..

To begin, we need to prime our pens [2]:

1. Using a swab, wipe the inner red seal.
2. Use a new needle; never reuse a needle or use one that is damaged or tampered with.
3. Attach the needle to the pen and turn it clockwise until it is firmly attached to the pen.
4. Remove both the inner and outer needle shields. You can dispose of the inner shield, but keep hold of the outer shield.
5. Turn the dose knob until you hear two clicks and the extended line is displayed on the dosage window.
6. Hold your pen vertically, and if any air bubbles appear, gently tap the solution to cause them to rise to the top.
7. Push the dosage knob, then wait a few seconds. Now there should be a ‘0’ shown on the dosage window, DO NOT INJECT! Some of the liquid should be let out of the tip of the needle; this means the pen is primed and ready for action.

(Please note that if no liquid is released, please repeat steps 5 to 7; do not repeat the steps more than twice. If you have repeated the steps twice and it is still not working, replace the needle and try again. If it is still not working, please consult a medical professional.

How to inject

-Choose where you will inject

-Turn the dose knob until ‘1’ is shown on the dose window [2]

-Push the needle into your skin. Ensure the dose counter is visible while performing this step.

-Press the dose knob until it stops, count to 5 in your head while still pressing the dose knob. When the dose window displays’ 0’, you can now remove the needle from your skin [2].

-Remove the needle from your skin. If you see a drop of the solution come out of the end of the needle, don’t worry. This is normal.

After you inject

-Place the outer shield back on the needle and dispose of in a sharps bin.

– Place the cap on the pen and place the pen in a safe storage location.

Storing your pen

After you inject yourself, you need to store your pen in a safe place. You can store it at room temperature, but don’t let the temperature exceed 30 degrees Celsius. Dispose of it within 30 days.

You can also store your Mounjaro pen in the fridge, but it must be disposed of within 30 days. And, of course, keep out of reach of children.

Dispose of the pen after receiving four weekly doses. There may be some liquid left in the pen after injecting four doses, but don’t try to squeeze out a ‘fifth dose’. This extra liquid serves as a buffer to ensure there are four doses and is not an accurate dose; therefore, do not inject this residual liquid [3].

Post-injection care

If you notice a bit of blood where you injected, do not be alarmed. Just clean the area. There may also be some bruising; this is perfectly normal and will subside within a couple of days.

If you are feeling pain or irritation during or after using Mounjaro, consider doing the following:

-Try an antihistamine tablet.

-Consider applying an antihistamine cream to the irritated area.

-Change injection sites weekly

-Apply a cotton swab to the injection site before injecting

-Numb the area with a cold compress before injecting.

-Take painkillers after you inject if you are feeling sore

-Apply a cold compress to combat any swelling that might occur post injection

Injection site reactions

Some people may experience mild skin reactions at the injection site where they administer Mounjaro.

In studies, about 1% of people taking a placebo (a fake treatment) had skin reactions. With Mounjaro, these reactions occurred more frequently as the dose increased: approximately 2% for the 5mg dose, 2.5% for the 10mg dose, and 3% for the 15mg dose [4].

This means injection site reactions are not very common and are only a little more likely at higher doses.

Common side effects at the injection spot can include:

• Skin rash
• Itching
• Eczema
• Swelling
• Redness

If you notice any of these, let your doctor know. They might suggest adjusting your dose, trying a different injection site, or using a cream to help alleviate irritation.

Mounjaro injections shouldn’t cause much pain. However, if you experience significant swelling, redness, or irritation, it may be a sign of an allergic reaction.

How to make Mounjaro Injections as painless as possible

• Take your time—don’t rush the injection. Injecting slowly can help reduce pain [5].
• If the area gets itchy or irritated, try an antihistamine tablet or cream.
• Change where you inject each week so you don’t keep using the same spot.
• Always clean your skin with a swab before you inject.
• You can use an ice pack to numb the area before the injection to help with discomfort.
• If you feel sore after injecting, you can take pain relief like paracetamol.
• Putting a cold compress on the spot after injecting can help with swelling.

These tips can help make your Mounjaro injections less painful and easier to manage.

What is a subcutaneous injection?

A subcutaneous injection is when medicine is given into the layer of fat just under your skin. This spot is used for some medicines, like Mounjaro, because they don’t work well if you swallow them—they get broken down in your stomach.

The fatty layer under your skin doesn’t have as much blood flow as your muscles, so the medicine is absorbed slowly. This slow, steady release is helpful for drugs that need to work over a longer time, like insulin or Mounjaro [6].

Subcutaneous injections are usually used for small amounts of medicine that won’t irritate your skin.

Are subcutaneous injections painful?

Subcutaneous injections usually aren’t very painful. Most people describe the sensation as a slight pinch or a quick sting when the needle is inserted. The pain is mild because the injection goes into the fatty layer just under the skin, which doesn’t have many nerve endings.

How much it hurts can depend on the type of medicine, the size of the needle, how the injection is administered, and your pain sensitivity. Moving injection spots each time and using good technique can help make it less uncomfortable.

Taking your time and injecting slowly can also help reduce pain. Studies show that going slow—about 30 seconds—can make it hurt less, but it doesn’t change how much bruising you get [5].

If you keep having pain or notice a lot of irritation, talk to your doctor or get in touch with us for a FREE Mounjaro weight-loss

What’s the difference between subcutaneous and intramuscular injections?

Where the medicine goes:

Subcutaneous (SC) injection: The medicine goes into the fatty layer just under your skin.

Intramuscular (IM) injection: The medicine is injected deeper, straight into the muscle.

Needle size:

SC injections use short, thin needles (about 4–16 mm long).

IM injections use longer, thicker needles (about 25–40 mm long) to reach the muscle.

How fast the medicine works:

SC injections are absorbed slowly, so the medicine is released over time.

IM injections are absorbed faster because muscles have more blood flow.

How much medicine can be given:

SC injections are for small amounts (up to 1–2 mL).

IM injections can handle larger amounts (up to 3–5 mL).

How it feels:

SC injections usually hurt less because they go into the fat, which has fewer nerves.

IM injections can hurt more because muscles have more nerves and the needle goes deeper.

Common uses:

SC injections: Insulin, blood thinners, some vaccines, and weight-loss medicines like Mounjaro and Wegovy.

IM injections Include vaccines (such as the flu shot), hormone shots, and some emergency medications.Top of Form

FAQs

Why is Mounjaro given as an injection under the skin?

• Mounjaro (and similar medicines like Wegovy) are given as injections because they are made from special proteins called peptides. If you swallowed them as a pill, your stomach and gut would break them down, and the medicine wouldn’t work.
• The injection lets the medicine slowly enter your body over a week, so you only need one dose each week. If you took it by mouth, you’d need to take it much more often, and it wouldn’t work as well.

How often should I change where I inject?

Change your injection spot every week to avoid skin irritation. You can use the same area (such as your stomach or thigh), but choose a different spot each time.

Can I reuse the needle?

Never use the same needle twice! Always use a fresh, clean needle for every injection. When you order Mounjaro from Medical Mojo, you get free needles with your medicine.

Why is my skin red or swollen after the injection?

Mild redness, swelling, or itching is common and usually goes away on its own. If one area is more sensitive, try a different spot next time.

Why do I have to start at the lowest dose (2.5mg)?

You start with 2.5mg so your body can adjust to the medicine, and you experience fewer side effects. Every four weeks, you can increase your dose. If higher doses cause side effects and you are still losing weight on a lower dose, you can go back down.

Do Mounjaro injections hurt?

As Mounjaro is an injection into your skin, there may be some slight pain or discomfort, but this should feel like a little pinch rather than excruciating pain.

Can I inject if I feel nauseous?

Feeling a little nauseous is a very common side effect of Mounjaro. More than one in ten people reported this symptom. Nothing is stopping you from injecting while you feel sick; however, if this sensation occurs post-injection, then it is definitely a side effect, and you should consult a health professional immediately.

Can I inject into the same spot week after week?

No, you cannot; you have to change where you inject Mounjaro every week. Repeated injection into the same spot can cause injection site reactions such as irritation, swelling or pain.

How to get Mounjaro from Courier Pharmacy

• Fill out a short online form:
  Answer some easy questions online so the team can check if Mounjaro is safe and right for you.
• Upload a recent photo:
  Send a clear, up-to-date picture of yourself to help confirm your identity.
• Show proof for higher doses:
  If you need a higher dose, you’ll need to show proof, like photos of your old pens or a note from your doctor, to show you’ve safely reached that dose.
• Share your GP’s details:
  Give your doctor’s contact information so the pharmacy can keep your GP updated about your treatment.
• Join a video call:
  Have a video call with the clinical team to make sure you’re using Mounjaro safely and to answer any questions you might have.

Why choose Courier Pharmacy?

• Great prices on Mounjaro pens
• Free needles, sharps bin, and alcohol wipes
• Free weight-loss coaching and support
• Free consultations, from your first chat to ongoing help
• Extra medicine if you have side effects that are hard to manage
• A supportive coaching program to keep you motivated

Courier Pharmacy is here to help you every step of the way on your weight loss journey.

This information is for general guidance only. For advice about your health, please talk to your doctor or healthcare provider.

References:

1. Courier Pharmacy (n.d.) Mounjaro Side Effects. Available at: https://courierpharmacy.co.uk/mounjaro-side-effects-2/ (Accessed: 15 July 2025).
2. Eli Lilly and Company Limited (n.d.) Mounjaro: Patient Booklet. Available at: https://uk.lilly.com/metabolic/assets/pdf/mounjaro-patient-booklet.pdf (Accessed: 15 July 2025).
3. Courier Pharmacy (n.d.) The Mounjaro Fifth Dose. Available at: https://courierpharmacy.co.uk/the-mounjaro-fifth-dose-2/ (Accessed: 15 July 2025).  
4. Mishra, R., Raj, R., Elshimy, G., Zapata, I., Kannan, L., Majety, P., Edem, D. and Correa, R., 2023. Adverse events related to tirzepatide. Journal of the Endocrine Society, 7(4), p.bvad016.
5. Mohammady M et al (2017) Slow versus fast subcutaneous heparin injections for prevention of bruising and site pain intensity. Cochrane Database of Systematic Reviews; 10: CD008077.
6. Medical Mojo (n.d.) How to inject Mounjaro: What is a subcutaneous injection? Available at: https://medicalmojo.co.uk/how-to-inject-mounjaro/#h-what-is-a-subcutaneous-injection (Accessed: 15 July 2025).