A rash on a GLP-1 drug is recorded in two places in the labels, and the place matters. A red, itchy or swollen patch where the needle went is an injection-site reaction, counted separately and covered on GLP-1 injection-site reactions. A rash, hives or itching elsewhere on the body is recorded as a hypersensitivity reaction — the labels' term for an allergic-type response. This page covers the second: the rates each current US label prints, the antibody finding that sits behind them, what the labels list as serious, and what the case-report literature adds. Labels read on DailyMed on 22 October 2026.
The hypersensitivity rate in each label
| Label (version) | Population | Drug | Placebo | What the label says it includes |
|---|---|---|---|---|
| Zepbound (v40, eff. 2026-08-28) | Adults, weight trials (Studies 1 and 2) | 2.1% immediate · 3.5% non-immediate | 0.4% · 2.7% | "majority … were skin reactions (e.g., rash, itching)" |
| Mounjaro (v40, eff. 2026-08-27) | Adults, diabetes trials | 3.2% | 1.7% | "sometimes severe (e.g., urticaria and eczema)" |
| Wegovy (v19, eff. 2026-06-18) | Teenagers, weight trial | rash 3% · urticaria 3% | 0% · 0% | Adults: rate given only by antibody status (below) |
| Saxenda (v22, eff. 2026-02-25) | Adults · teenagers | urticaria 0.7% · rash 3.2% | 0.5% · 0% | Rash in the paediatric table; urticaria in adults |
| Victoza (v31, eff. 2025-10-14) | Adults, diabetes | 0.8% | 0.4% (comparator) | Immunogenicity-related events; urticaria "approximately one-half" |
| Foundayo (v10, eff. 2026-07-29) | Adults, weight trials 1 and 2 | 0.5% | 0.3% | "including anaphylactic reaction" |
| Trulicity (v62, eff. 2026-06-16) | Adults | 0.5% | — | "systemic … sometimes severe (e.g., severe urticaria, systemic rash, facial edema, lip swelling)" |
| Ozempic (v20) and semaglutide tablets (v14) | Post-approval reports | not estimable | — | "anaphylaxis, angioedema, rash, urticaria" |
Section 6 of each label. A placebo rate is shown only where the label prints one.
Three readings from the table:
- Tirzepatide prints the highest trial rates in the class: about 1.7 extra immediate reactions per 100 people on Zepbound, and 1.5 extra per 100 on Mounjaro, over placebo. (Our subtraction from the label percentages.) Placebo groups had reactions too — 2.7% non-immediate on Zepbound's placebo — which is a reminder that rashes are common in any large group of people over a year.
- Zepbound splits the reactions by timing. The excess is concentrated in reactions within a day of a dose (2.1% vs 0.4%); later reactions differ much less (3.5% vs 2.7%). No other GLP-1 label reports that split.
- Rash in teenagers shows up where it is absent in adults. Both the Wegovy and Saxenda paediatric tables record rash at about 3% against none on placebo, in trials of 201 (Wegovy) and 251 (Saxenda) young people, randomised 2:1 and 1:1 respectively. Small groups make single-digit percentages unstable, which the labels do not comment on.
The antibody finding
All GLP-1 drugs are peptides, and some people's immune systems make antibodies to them. Two labels report hypersensitivity by antibody status:
| Label | With anti-drug antibodies | Without |
|---|---|---|
| Zepbound (hypersensitivity reactions) | 6.2% | 3% |
| Mounjaro, pool of seven adult trials | 4.1% (106 / 2,570) | 3.0% (73 / 2,455) |
| Wegovy, adult weight trials (allergic reactions) | 16% (8 / 50) | 7% (114 / 1,659) |
Section 6.1 of each label; the labels refer to section 12.6 for antibody methods.
Antibodies are far more common on tirzepatide than on semaglutide — the Wegovy comparison rests on 50 people with antibodies. In every row, most people with antibodies had no reaction, and the labels present the figures as an association, not a cause. Injection-site reactions show a stronger version of the same pattern on Zepbound (11.3% with antibodies against 1% without), tabled on the injection-site page.
What the labels treat as serious
Every label read lists anaphylaxis and angioedema as serious hypersensitivity reactions reported with the drug or its class, and makes known serious hypersensitivity to the drug a contraindication. The Zepbound label adds a caution for people with a history of anaphylaxis or angioedema on another GLP-1 drug, "because it is unknown whether such patients will be predisposed to these reactions with ZEPBOUND". The patient information on all nine labels lists the signs of a serious allergic reaction as 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 — and tells the reader to get medical help right away. That is the labels' instruction, reported here as written.
What the case reports add
The trial tables group skin reactions into one line. Published case reports describe individual reactions in more detail, and they are where rarer patterns appear. A PubMed search on 22 October 2026 for a named GLP-1 drug together with rash, urticaria, drug eruption, pemphigoid or panniculitis, limited to case reports, returned 20 records. Among them:
| Reaction described | Drug | Source |
|---|---|---|
| Morbilliform (measles-like) drug eruption | Tirzepatide | JAAD Case Reports, August 2026 |
| Papular granuloma annulare | Tirzepatide | JAAD Case Reports, August 2026 |
| Symmetrical intertriginous and flexural exanthema | Tirzepatide | JAAD Case Reports, May 2026 |
| Possible trigger of bullous pemphigoid | Tirzepatide | J Dtsch Dermatol Ges, August 2026 |
| Fixed drug eruption | Semaglutide | JAAD Case Reports, February 2025 |
| Atypical pustular drug eruption | Semaglutide | Cureus, January 2026 |
| Bullous pemphigoid | Semaglutide (2021), dulaglutide (2019) | JAAD Case Reports; Geriatr Gerontol Int |
| Cutaneous sarcoidosis; recurrence of solar urticaria | Semaglutide; liraglutide | Skin Health and Disease, 2026 |
Titles and abstracts read on PubMed, 22 October 2026. Full reference list below.
A case report is one person. It shows a reaction can happen and describes how it looked and resolved; it cannot say how often it happens or prove the drug caused it, although the authors of the sarcoidosis and solar urticaria report scored both links as "probable" on a standard causality scale (the Naranjo score), and in the sarcoidosis case the lesions cleared when the drug stopped. Bullous pemphigoid, a blistering condition, is better known with a different class of diabetes drug (DPP-4 inhibitors); the GLP-1 reports are few by comparison — 14 PubMed records in total mention a named GLP-1 drug and pemphigoid.
Adverse-event report counts
FDA's adverse event database (openFDA, data updated 30 July 2026, queried 22 October 2026) holds, among reports naming each molecule: tirzepatide — rash 1,294, pruritus 1,234, urticaria 783 of 160,663 reports; semaglutide — rash 1,149, pruritus 1,202, urticaria 390 of 73,001; liraglutide — rash 732, pruritus 641, urticaria 398 of 50,705; dulaglutide — rash 910, pruritus 836, urticaria 413 of 88,160. These count reports, which can list several symptoms and several drugs; they are not rates and cannot be compared across drugs as risks.
What this page cannot tell you
- How often a rash on semaglutide happens in adults. Ozempic's label gives no trial rate, and Wegovy's adult rate is given only split by antibody status.
- Whether a particular rash is caused by the drug. Many things cause rashes; the labels and the case literature cannot decide one person's case.
- Whether a reaction will recur on another GLP-1 drug. Zepbound's label says this is unknown.
A rash that spreads, blisters, involves the mouth or eyes, or comes with swelling or breathing trouble is in the labels' serious category. Any new rash on a GLP-1 drug is for the prescriber or a clinician to assess. Hair and skin changes that are not allergic — hair loss, and the skin sensations some people describe as burning or tenderness — are on GLP-1 hair loss and skin sensitivity on GLP-1 drugs.
Sources
- DailyMed prescribing information read 22 October 2026, section 6 (and 4, 5, 17 where cited): Zepbound v40; Mounjaro v40; Wegovy v19; Ozempic (adec4fd2-6858-4c99-91d4-531f5f2a2d79) v20; Rybelsus/Ozempic tablets (27f15fac-7d98-4114-a2ec-92494a91da98) v14; Saxenda (3946d389-0926-4f77-a708-0acb8153b143) v22; Victoza (5a9ef4ea-c76a-4d34-a604-27c5b505f5a4) v31; Trulicity (463050bd-2b1c-40f5-b3c3-0a04bb433309) v62; Foundayo (8ac446c5-feba-474f-a103-23facb9b5c62) v10.
- PubMed case reports (abstracts read 22 October 2026): PMID 42541308 (tirzepatide morbilliform eruption), 42499401 (granuloma annulare), 42064416 (intertriginous exanthema), 42656044 (bullous pemphigoid, tirzepatide), 39845462 (fixed drug eruption, semaglutide), 41658769 (pustular eruption, semaglutide), 34466645 (bullous pemphigoid, semaglutide), 31823494 (bullous pemphigoid, dulaglutide), 42813201 (sarcoidosis and solar urticaria).
- PubMed searches, 22 October 2026: named GLP-1 drug or class AND (rash OR urticaria OR "drug eruption" OR pemphigoid OR panniculitis), case reports — 20 records; named GLP-1 drug or class AND pemphigoid — 14 records.
- openFDA drug adverse event API, data last updated 2026-07-30, queried 22 October 2026.