Short answer: Yes. All four GLP-1 labels warn that serious allergic reactions, including anaphylaxis and swelling of the face or throat (angioedema), have been reported, and none may be used after a serious reaction to the drug. Milder reactions, mostly rash and itching, were more common: 5% on Zepbound vs 3% on placebo in weight-loss trials, and 3.2% vs 1.7% on Mounjaro.
Ozempic (section 5.8), Wegovy (5.7), Mounjaro (5.4) and Zepbound (5.6) each carry a hypersensitivity warning: serious reactions such as anaphylaxis and angioedema have been reported. Each lists a prior serious reaction to the drug or its ingredients as a reason not to use it (section 4).
The labels also say anaphylaxis and angioedema have been reported with other GLP-1 medicines, and that it is unknown whether someone who had one of these reactions with another GLP-1 medicine is more likely to have it again. They advise caution in that case.
| Label | Allergic (hypersensitivity) reactions | Injection site reactions |
|---|---|---|
| Zepbound, weight-loss trials | 5% at each dose vs 3% placebo; severe 0.1% vs 0% | 6-8% vs 2% placebo |
| Mounjaro, diabetes trials | 3.2% vs 1.7% placebo | 3.2% vs 0.4% placebo |
| Wegovy, adult weight-loss trials | Serious reactions reported; rates tied to antibodies below | 1.4% vs 1% placebo |
| Ozempic, diabetes trials | Serious reactions reported after approval | 0.2% |
The Zepbound label splits its numbers by timing: reactions within a day of a dose happened in 2.1% vs 0.4% on placebo, and later ones in 3.5% vs 2.7%. It says most were skin reactions such as rash and itching.
Many people make antibodies to these drugs, and those who do had more reactions. On Zepbound, 64.5% developed anti-tirzepatide antibodies in the weight-loss trials; allergic reactions happened in 6.2% of them vs 3% of those without, and injection site reactions in 11.3% vs 1%. On Wegovy, allergic reactions happened in 16% (8 of 50) of people with anti-semaglutide antibodies vs 7% without.
The Mounjaro label says antibodies had no clinically significant effect on how well the drug worked. They mainly show up as more skin and injection site reactions.
The Zepbound Medication Guide lists the signs of a serious allergic reaction: swelling of the face, lips, tongue or throat; problems breathing or swallowing; severe rash or itching; fainting or feeling dizzy; and a very rapid heartbeat. It says to stop the medicine and get medical help right away if these occur. The anaphylaxis entry explains the most serious form.
A red or itchy spot where the needle went in is more often an injection site reaction. Logging the site and any reaction with each dose, as Dose Track does, shows whether it follows one spot, one pen or every dose, which helps the prescriber tell the two apart.
Read more on Dose Track: Anaphylaxis · Injection site reaction · Mounjaro side effects · Wegovy side effects