What Is GLP-1 Receptor Agonist Allergy?

What are GLP-1 Receptor Agonists?
They are injectable medications prescribed to help people with obesity or type 2 diabetes. Some common name brands of FDA approved products include: Ozempic, Wegovy, Mounjaro, Saxenda, Trulicity and Zepbound. Due to high demand, some pharmaceutical companies make “compounded” versions of GLP-1 receptor agonists which are not FDA approved. These versions may have slightly different ingredients and may not be safe. 

These medications mimic the function of a natural hormone produced in your body called glucagon like peptide GLP-1. GLP-1 works to control blood sugar and appetite. The short peptides in these medications are chemically modified so that they last longer in the body and work better than the naturally occurring GLP-1 hormone. Some GLP-1 medications are made directly from chemical reactions while others are made in yeast or other mammalian cells in a lab. They are then purified prior to being distributed as medications. 

What are the common side effects of these medications? 
Injection site reactions include pain, redness, itching or raised rubbery lumps. Gastrointestinal reactions can include nausea, vomiting or diarrhea. 
 
What can you do to minimize injection site reactions? 
Mild injection site reactions usually improve on their own. Cold compresses can be used to relieve itching and swelling. Rotate the injection site for each dose to prevent irritation and prevent rubbery lumps. 
 
What is GLP-1 Receptor Agonist allergy? 
Some patients may be allergic to these medications. This happens because your body’s immune system thinks that the medication is unfamiliar or harmful and tries to reject it. 
 
What happens during an allergic reaction? 
The body sees the medication as a foreign substance and produces an immune response against it. This results in the release of certain chemicals such as histamine, which cause signs of an allergic reaction. 
 
What are the common signs of an allergic reaction? 
An allergic reaction to these medications may be: 
 
Mild 
•    Itchy skin, rash or hives 
•    Swelling of the hands or feet 

Severe allergic reaction or anaphylaxis 
•    Swelling of face or lips or throat closing 
•    Trouble breathing  
•    Dizziness or fainting 

Allergic reactions can be immediate with the onset of symptoms happening in less than two hours. Delayed reactions like a rash can appear days to months after starting the medication. Sometimes the immune response may also lead to rapid elimination of the medication from the body, reducing the effectiveness of the medication. 

What should you do if you have an allergic reaction to your medication? 
Stop using the medication and call your doctor right away. Call 911 or go to the nearest emergency room if: 
•    You have difficulty breathing.
•    Are feeling dizzy or fainting.
•    Have swelling of the face or lips or throat closing. 

Your doctor may refer you to be evaluated by an allergist.
 
What happens at the allergist’s clinic? 
•    The allergist will obtain detailed history of your symptoms. 
•    Based on your symptoms, the allergist can decide if the medication needs to be completely stopped or can be restarted. 
•    If you also agree to restart the same medicine, cautious drug reintroduction or a drug challenge can be done in the clinic. This is the best way to determine if you are allergic or not to the medication. 
•    During a direct drug challenge, the medication is given as one single dose or multiple, gradually increasing doses under supervision in the allergist's office.  
 
What happens if you are allergic to a GLP-1 Receptor Agonist? 
Your allergist may ask you to: 
•    Stop taking the medication that caused the reaction. 
•    Try a different GLP-1 receptor agonist that you may be able to tolerate safely. It is important to tell your allergist which product you are taking (including the manufacturer).  
•    If no other safe alternatives are available, a process called induction of tolerance can be done. During this process, you will be given gradually increasing doses of the medicine under doctor’s supervision. This process helps your body to get used to the medicine that you are allergic to. 
 
The AAAAI's Find an Allergist / Immunologist service is a trusted resource to help you find a specialist close to home.

1/16/2026