Jump to: Understanding injection sites | Why you need to rotate injection sites | How Mounjaro works at different sites | Proper injection technique | Common injection site mistakes | Take home message
There’s no clinical evidence that the effectiveness of Mounjaro changes in different injection sites. You can inject Mounjaro (tirzepatide) into your abdomen, thighs, or the back of your upper arms.
Research indicates that Mounjaro is absorbed similarly across all injection sites, with the medication taking between 8 to 72 hours to reach peak concentration in your bloodstream.
Still, it’s recommended to rotate your injection site weekly. The abdomen is often recommended as the primary injection site due to its accessibility and typically having enough fatty tissue for proper absorption.
However, the choice ultimately depends on your comfort and which area you find easiest to access.
Understanding injection sites
Mounjaro must be injected into the fatty layer beneath your skin (subcutaneously).
Here’s what you need to know about each injection site for Mounjaro:
1 – Abdomen
Choose an area at least 5cm (2 inches) from your belly button. The abdomen typically has sufficient fatty tissue and is easy to access when self-injecting.
2 – Thighs
Select the front or outer part of either thigh. This area provides a large surface for rotation and is easily accessible when sitting.
3 – Upper arms
Use the fatty area on the back of your upper arms. While this site works equally well, you might need assistance safely injecting here. Some people prefer this location as it’s less visible.
Why you need to rotate injection sites
Rotating your injection sites weekly is crucial for three key reasons:
1. It prevents lipohypertrophy (fatty lumps under the skin) that can develop from repeatedly injecting in the same area
2. It helps maintain consistent absorption of the medication, as scar tissue from frequent injections in the same spot may affect how well your body processes Mounjaro
3. It reduces your risk of injection site reactions, such as redness, itching, or bruising
How Mounjaro is absorbed
Understanding how Mounjaro works within your body helps explain why all injection sites are equally effective.
After injection, the medication begins through your body’s tissues, starting in the fatty layer beneath your skin.
From there, it gradually moves into your nearby blood vessels, much like water being absorbed by a sponge.
Your bloodstream then carries Mounjaro throughout your body, allowing it to reach its target receptors in your brain and digestive system, where it helps to lower appetite and blood sugar levels.
While there might be slight variations in absorption speed between different injection sites, Mounjaro’s long half-life of approximately 5 days ensures these minor differences don’t impact the overall effectiveness of the medication.
Mounjaro is a long-acting medication that reaches a ‘steady state’ after 4-8 weeks of taking the drug.
This steady state means that the drug levels remain stable in the bloodstream, ensuring the impact of the drug is consistent across the week. This means hunger levels remain lower rather than rising and falling.
Proper injection technique
To ensure the safe and effective administration of Mounjaro:
- Always inject at a 90-degree angle into the fatty tissue beneath your skin
- Avoid areas with visible blood vessels, moles, scars, or bruises
- Don’t inject through clothing
- Use a new site at least 2.5cm (1 inch) away from your previous injection
Common injection site mistakes to avoid
1. Reusing the same spot frequently: This can lead to tissue damage and affect how well your body absorbs the medication
2. Injecting into muscle instead of fat: This can cause pain and may affect how your body processes Mounjaro
3. Not cleaning the injection site: Always use an alcohol swab to reduce infection risk
4. Choosing areas with little fatty tissue: This can make the injection more uncomfortable and affect absorption
Take home message
While you might hear various theories about the ‘best’ place to inject Mounjaro, research shows that the abdomen, thighs, and upper arms are all equally effective. The most important factors are proper injection technique and consistent site rotation.
Focus on finding injection sites that feel comfortable and accessible for you, and establish a regular rotation pattern to prevent tissue damage and maintain consistent absorption.
Remember that everyone’s experience with Mounjaro is unique. If you’re unsure about injection techniques or experience any concerns, your healthcare provider can offer personalised guidance and support.
Second Nature’s medication programmes
Second Nature currently provides Mounjaro as part of our Mounjaro weight-loss programme.
Why should you choose Second Nature over other medication providers if you’ve decided to try Mounjaro (assuming you’re eligible)?
For peace of mind.
Second Nature has worked with the NHS for over 6 years, providing weight-loss programmes across the UK.
While our Mounjaro weight-loss programme is private and not currently used by the NHS, we’ve built the programme focusing on scientific evidence, patient safety, and data security.
We hope that our 6+ years of working with the NHS and building a track record of effective weight-loss results will give you peace of mind to give us a try.
