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Mounjaro
Learn how to prepare, administer and maintain your Mounjaro treatment cost-effectively, with guidance on potential side-effects.
Medical Director
Our main priority is to provide you with continuity of care. For some, this may be switching to a treatment that costs less per pen, but for others it will mean staying on their current treatment. Ultimately, we are here to support your decision around your treatment.
If you want to stay on Mounjaro, you can continue your treatment plan without any changes. If you are feeling unsure how the price changes will affect you, please get in touch. Our clinical team are here to support you with guidance and advice on selecting your next dose of Mounjaro and there options when it comes to staying on your current treatment.
You can get in touch via our support form or check our help centre for immediate answers to your questions.
With MedExpress you'll receive 1 Mounjaro pen each month; this pen contains 4 doses. You'll also receive 4 disposable needles and you must use a new one each time you inject.
Preparing and checking your Mounjaro
- Remove your medication from the refrigerator and make sure all the items you need are nearby on a clean surface. This includes your medication pen, alcohol swab, sharps bin and disposable needle.
- Wash your hands thoroughly with soap.
- Pull off the pen cap.
- Check your pen for any signs of damage and check that the medication is clear and colourless to slightly yellow in the window of the pen.
- Do not use medication if the pen has signs of damage or if the medication is cloudy or discoloured.
- Wipe the red inner seal of the pen with one of the alcohol wipes.
- Select a needle to use for your injection and check the paper tab and the outer needle cap for damages. If you see any damage, dispose of the needle in a sharps bin as this could affect sterility.
- Tear off the paper tab from the needle, then push the needle onto the pen and twist until it's secure.
- Remove both caps from the needle, keeping the outer cap for later to safely dispose of your medication.
Priming your Mounjaro pen
- Slowly turn the dose knob until you hear 2 clicks and the extended line is shown in the dose window. This is the prime position.
- With the needle pointing upwards, tap the cartridge holder gently to collect air bubbles at the top.
- Release some medicine into the air by pushing the dose knob in until it stops, then slowly count to 5 while holding the dose knob. A small amount of medicine should come out the tip of the needle and the "0" icon must be shown in the dose window.
- If a small amount of medicine is not released, repeat these steps an additional 2 times. After 2 failed priming attempts, replace the needle and try once more.
- A visible droplet at the needle tip confirms success. If absent after 3 total attempts (2 with the original needle and 1 with new needle), contact MedExpress.
Choosing an injection site
When choosing an injection site remember to choose one where you can see the pen window and is easily accessible. Our clinical team also recommends rotating your injection sites each time you inject to reduce the possibility of injection site reactions.
- Choose an injection site: upper arms, stomach or the front of your thighs.
- Clean the site with the alcohol swab provided.
Administering your Mounjaro
- Turn the dose knob until it stops and the ‘1’ icon is shown in the dose window.
- Position the pen at the injection site at a 90 degree angle.
- Insert the needle into your skin and inject the medication by pressing and holding the dose button until "0" appears, then continue holding for 5 seconds to ensure full delivery.
- Remove the needle from your skin.
- If blood appears at the injection site, press on it lightly with a clean tissue, but do not rub the area.
It didn't hurt… Did the dose actually go in?
It's very common to feel little or nothing during a GLP-1 injection. The needles used in these pens are extremely fine, so the injection is designed to be as gentle as possible.
Because of that, many people are surprised by how easy it feels. Some even wonder if the dose actually went in.
The best way to check is to look at the pen. If you saw the dose counter return to zero, held the pen in place for the recommended time (5 seconds), and the plunger has moved down inside the pen, your medication has been delivered.
Not feeling much during the injection doesn't mean anything went wrong. In fact, it often means the pen worked exactly as it should.
Disposing of medication
- Lead the needle tip into the outer needle cap on a flat surface. Once the needle is covered, carefully push the outer needle cap completely on.
- Unscrew the needle and dispose of it in your sharps bin.
- Put the pen cap on your pen after each use and store it safely in the refrigerator until your next dose.
What if the pen doesn't work?
If you pressed the dose button and the number in the dose window didn't change from "1" to "0", or the button couldn't be pressed at all, your dose may not have been delivered. In that case, don't attempt to inject again straight away. Contact our clinical team who will advise you on next steps.
You won't waste your dose: How your pen protects you
It's completely normal to feel a bit nervous before your first few injections, especially when the medication is expensive. Many people worry about doing something wrong or wasting a dose. The reassuring thing is that injection pens are carefully designed to make dosing simple and reliable.
The pen delivers a fixed dose each time, so you can't accidentally dial up more medication than intended. The mechanism inside the pen controls exactly how much medication is released, helping ensure the correct amount is delivered with each injection.
Priming the pen before use helps make sure the medication can flow smoothly through the needle, and the needles themselves are very thin and designed for single use.
Even if you feel a little hesitant pressing the button, the pen is built to work reliably when the basic steps are followed. And if you happen to hold the pen in place slightly longer than recommended, that's absolutely fine. It won't affect your dose.
Blood, bumps and bruises. What's normal after injecting?
Answer? All of the above. After an injection, you might notice a few small changes in your skin. This can include a tiny spot of blood, a small raised bump where the medication was injected, or mild bruising that appears later. These reactions are quite common and usually settle on their own.
They don't mean the injection was done incorrectly, and they don't affect whether your medication was delivered properly. More significant reactions are rare. If you notice severe pain, large swelling, or signs of infection around the injection site, it's a good idea to seek medical advice.
Where should I inject? The stomach v. thigh argument
You can inject your medication into your stomach, thigh or upper arm. All of these approved injection sites work equally well.
Because of that, there isn't a "best" place to inject. The right spot is simply the one that feels most comfortable for you and fits easily into your routine.
Some people prefer the stomach because it's easy to see and reach. Others prefer the thigh because it feels more comfortable when sitting down.
What matters most isn't the exact location; it's consistency. Choosing a spot that works for you and rotating your injection sites regularly helps keep the process simple and comfortable over time.
Your medication will work the same whichever approved site you choose.
Finding your right dose
The right dose is the one that feels sustainable — where you’re seeing steady progress and feeling well along the way. For many people, that might mean losing around 0.5–1kg per week, but everyone’s journey looks a little different.
If your weight loss feels too fast or you have uncomfortable side effects, it’s absolutely fine to stay on a lower dose for longer. What matters most is finding a pace and dose that work for you.
Our clinical team will continue to check in on your progress to make sure Mounjaro is safe, effective, and helping you move toward your goals.