Injection site reactions are a common side effect when using injectable weight loss medications such as Mounjaro® and Wegovy®. These reactions are usually mild and temporary.
This article explains what injection site reactions are, how to reduce irritation, and when to seek medical advice.
Overview
Use this article if you notice redness, irritation, or discomfort at your injection site while using injectable weight loss medication.
This guide covers:
What injection site reactions are
How common injection site reactions are
How to reduce injection site irritation
When to contact a GP or call 111
When to seek urgent medical help
What are injection site reactions?
Injection site reactions can occur in up to 1 in 10 people using injectable weight loss medications such as Mounjaro® or Wegovy®.
Common symptoms include:
Redness
Mild swelling
Itching
Soreness at the injection site
These reactions are usually mild and settle on their own.
How to reduce injection site reactions
To help reduce irritation and discomfort when using weight loss injections, MedExpress recommends:
Rotate your injection site
Alternate your injection location each week between:
Lower stomach
Thigh
Upper arm
Buttocks
Rotating injection sites helps prevent repeated irritation in the same area.
Use correct injection technique
Using the correct technique can reduce the risk of injection site reactions.
If using Wegovy®, follow the approved Wegovy® injection technique
If using Mounjaro®, follow the approved Mounjaro® injection technique
When to contact your GP or call 111
Contact your GP or call NHS 111 if you notice:
Intense redness around the injection site
A rash that worsens or spreads
Warmth or pus at the injection site
Fever or chills
When speaking with a healthcare professional, explain that you are using injectable weight loss medication.
When to seek urgent medical help
Call 999 or go to A&E immediately if you experience:
Difficulty breathing
Swelling of the lips, tongue, or throat
These symptoms may indicate a severe allergic reaction (anaphylaxis) and require urgent medical attention.
Key takeaway
Injection site reactions with Mounjaro® and Wegovy® are common and usually mild. Rotating injection sites and using proper injection technique can help reduce irritation. Seek medical advice if symptoms worsen or signs of infection or allergy appear.
If you still need help after reviewing the information above, additional assistance is available.