Mounjaro Injection Sites: Where To Inject Mounjaro

If you’re new to weight loss injections or have recently switched to Mounjaro, it’s important to understand the best injection sites and how to administer your medication safely. In this blog post we’ll cover dosage and storage instructions for your weight loss treatment, as well as how and where to inject Mounjaro for best results.

Article Summary:

• Mounjaro is the brand name for a weight loss treatment containing the active ingredient tirzepatide, a dual GIP and GLP-1 receptor agonist.
• The treatment is injected once a week into the fatty tissue of your upper arm, stomach or thigh, to help you reach a healthy weight. This is called your injection site.
• You can inject into the same area of your body each week, but it’s best to choose a slightly different spot to reduce the risk of irritation. Your choice of injection site doesn’t impact the effectiveness of the medication.

What is Mounjaro?

Mounjaro is an MHRA-approved weight loss injection that contains the active ingredient tirzepatide. It’s only available on prescription after a clinical assessment to decide whether you’re eligible. Your clinician will review your medical history to assess the risks and check your eligibility, including your body mass index (BMI) and obesity-related health conditions.

Other popular weight management medications, Wegovy and Saxenda, belong to a class of drugs called glucagon-like peptide-1 (GLP-1) receptor agonists. This means they mimic the GLP-1 hormone that is naturally released in the digestive tract when we eat. This then tells the body to produce more insulin, which controls blood sugar levels and regulates appetite by sending signals to tell your body it's full. This helps reduce the likelihood that you will be driven to overeating. [1]

Mounjaro is slightly different, as it is both a GLP-1 and glucose-dependent insulinotropic peptide (GIP) receptor agonist. Also known as a dual agonist or ‘twincretin’, meaning it works in two ways. [2]

Like Wegovy, it mimics the GLP-1 hormone to help control blood sugar, but it also mimics the GIP hormone. This helps enhance insulin sensitivity, reduce hunger signals in your brain to reduce appetite, and can improve fat metabolism. [3]

In clinical trials, tirzepatide has been shown to help people experience weight loss of 22.5% after 72 weeks of treatment. [4] However, all weight loss medications must be prescribed alongside lifestyle changes, such as a reduced calorie diet and increased exercise, to achieve lasting results.

What your Mounjaro injection looks like

Mounjaro is taken as a once-weekly injection and is administered using an injection pen. Mounjaro KwikPen is a disposable, multi-dose pre-filled pen for single patient use (you should never share it). The pen contains 4 fixed doses, with 1 dose taken each week.

When you receive your Mounjaro medication, the Patient Information Leaflet inside the box will provide detailed instructions on how to administer your injection, including which injections sites to use. You’ll also receive a free sharps container with your first order. You can get in touch with your clinical team here at MedExpress if you have any questions or concerns.

How to use Mounjaro

You’ll take your Mounjaro medication on the same day each week, at any time of the day. If that day is no longer convenient for you to administer your medication, it is possible to switch your day. Just make sure there are at least 3 days (72 hours) between your last dose and your next (new weekly) one. [6]

Dosage instructions

Mounjaro is an injectable treatment that requires titration. This is a way of gradually increasing the doses each month, to help you get its maximum benefits with minimal side effects.

A typical Mounjaro dosing schedule would start at 2.5 mg for weeks 1-4 before reaching 15mg from week 21 onwards. This is also known as your maintenance dose, meaning the most effective dose to manage your weight long-term while balancing side effects. [5]

You won’t have to work out your doses yourself, as your injection pens will come pre-filled with 4 doses. And your dose increases will be determined by your MedExpress clinical team on an ongoing basis. You can read more in our full Mounjaro dosing guide here.

Preparing the Mounjaro pen

Before administering your medication, you’ll need to get the injection pen ready. First, remove it from the refrigerator, leaving the cap on until you’re ready to inject. Next, read the label to check the dose and expiration date to ensure that it’s in date. Then check the pen to make sure it’s not damaged and the solution is not frozen or cloudy. [6]

When you’re ready to inject, you’ll need to select a new needle and check it to ensure it's not damaged. You’ll need to do this each time you administer your medication. If you see any damage, dispose of the needle in a sharps bin. Do not use a damaged needle as it may not be fully sterile and safe to use.

Then, you need to push the needle onto the pen and twist until it's secure. Remove both caps, disposing of the inner cap and keeping the outer one for later to safely dispose of your medication.

Priming the Mounjaro pen

This is an important step in the preparation part of your injection. Priming removes air from the cartridge and makes sure that your pen is working correctly. Your pen has been primed if a small amount of medicine comes out of the tip of the pen needle.

You can prime your pen by slowly turning the dose knob, until you hear 2 clicks and the extended line is shown in the dose window. Then, 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.This will expel a small amount of medicine, but don’t worry, it won’t affect your dose.

Choosing the best Mounjaro injection site

Your medication must be delivered via subcutaneous injection, which means it goes into the fatty tissue just under the skin. Never inject into a muscle or a vein. You should also try to avoid areas of scarring, bruising, stretchmarks, rashes or broken skin.

You can choose to inject it in your stomach (abdomen), thigh or upper arm. The area you pick is known as your ‘injection site’. Just remember to clean the area with the alcohol swab provided before you inject. [6]

So long as you inject your medication as directed into one of these three injection sites, it doesn’t matter which one you choose. Some people find their abdominal area is the easiest to access for full visibility, or you might like to use your upper arm if someone is injecting it for you. The best Mounjaro injection site is the one you’re most comfortable with.

Each week, inject into a different spot to help prevent inflammation of the fatty tissue, scarring or injection site reactions. You can use the same body part every week if you prefer, but avoid injecting right next to the previous week’s dose, to help minimise skin irritation. [7]

Administering the injection correctly

To administer your medication, turn the dose knob until it stops and the ‘1’ icon is shown in the dose window.

Then, position the pen at your chosen injection site and insert the needle into your skin by holding down the dose knob while you count to 5. Once the ‘0’ icon is visible in the dose window you can remove the needle from your skin.

What to do with your injection afterwards

Injections and injection pens must be disposed of safely. We’ll send you a sharps container with your first Mounjaro order to put your used injection pens in. Make sure you keep your container out of the reach of children.

When you’re ready to dispose of it, do not put any element in your household recycling. When your sharps bin is full you can take it to your local pharmacy to be disposed of, or it may be able to be collected by your local council.

What to do if a dose is missed

There might be a time when missing your usual injection day is unavoidable. If this happens, just take the missed dose as soon as possible within 4 days (96 hours). If it has been more than 4 days since the missed dose, skip that one entirely and take your next dose on the next regularly scheduled day. [6]

Thinking of trying Mounjaro to help your weight loss goals? Find out what treatment might be suitable for you on our website.

References

1. Solan M. Understanding new weight-loss drugs [Internet]. Harvard Health. 2023 [cited 2024 Jul 3]. Available from: https://www.health.harvard.edu/staying-healthy/understanding-new-weight-loss-drugs
2. Dutta P, Kumar Y, Babu AT, Giri Ravindran S, Salam A, Rai B, et al. Tirzepatide: A Promising Drug for Type 2 Diabetes and Beyond. Cureus [Internet]. 2023 May 1;15(5):e38379. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10231274/
3. Nguyen TMD. Adiponectin: Role in Physiology and Pathophysiology. International Journal of Preventive Medicine [Internet]. 2020 Sep 3;11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7554603
4. Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, et al. Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine [Internet]. 2022 Jun 4;387(3). Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
5. Mounjaro: Uses, Dosage, Side Effects & Warnings [Internet]. Drugs.com. Available from: https://www.drugs.com/mounjaro.html
6. How to Use, Dosing & Side Effects | Mounjaro® (tirzepatide) [Internet]. mounjaro.lilly.com. Available from: https://mounjaro.lilly.com/how-to-use-mounjaro#how-to-use
7. Hirsch LJ, Strauss KW. The Injection Technique Factor: What You Don’t Know or Teach Can Make a Difference. Clinical Diabetes : A Publication of the American Diabetes Association [Internet]. 2019 Jul 1;37(3):227–33. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6640874/