Semaglutide Excipient, Not the Drug Itself, Likely Caused Rare Pustular Skin Reaction | Research

The takeaway

A patient developed an AGEP-like pustular skin eruption after increasing semaglutide dose, but investigation revealed the excipient propylene glycol was the likely culprit, not semaglutide itself.

Excipient, not drug
The pustular skin reaction was attributed to propylene glycol in the formulation, not the semaglutide peptide itself

What the researchers found

An AGEP-like skin reaction after semaglutide dose increase was attributed to the excipient propylene glycol rather than semaglutide, highlighting the importance of ingredient analysis in adverse drug reactions.

Why it matters

With millions taking semaglutide, understanding that adverse reactions may be caused by excipients rather than the active peptide itself has important implications for patient management and formulation alternatives.

How the study worked

Single case report with clinical documentation, histopathological analysis, and systematic ingredient/excipient investigation.

What this study cannot tell us

Single case report. Cannot definitively prove propylene glycol causation. The atypical AGEP timeline complicates diagnosis.

How to read the evidence

Single case report with careful clinical reasoning and ingredient analysis. Documents an important diagnostic principle.

When this study was published

Published in 2025.

The bigger picture

As peptide drugs become widely used, distinguishing reactions to the active peptide from reactions to formulation excipients is crucial for appropriate clinical management.

Questions still open

Should patients with propylene glycol sensitivity avoid certain semaglutide formulations?
How common are excipient-related reactions among GLP-1 drug users?
Would reformulation without propylene glycol prevent these reactions?

Common questions

Did Ozempic cause the rash?

Likely not the active ingredient (semaglutide) — investigation pointed to propylene glycol, an inactive ingredient in the formulation, as the probable cause of the skin reaction.

What should patients do if they get a rash from semaglutide?

Report it to your doctor immediately. The reaction may be to an inactive ingredient rather than semaglutide itself, meaning a different formulation might be safe to use.

Read the original research

Semaglutide-Induced Atypical Pustular Drug Eruption: A Case Report.

Cureus, 18(1), e101016

View on PubMed ↗Publisher’s paper ↗

Citation

Elliott, Destinee C; Veon, Francesca L; McBride, Jeffrey D; Levin, Jarad. (2026). Semaglutide-Induced Atypical Pustular Drug Eruption: A Case Report.. Cureus, 18(1), e101016. https://doi.org/10.7759/cureus.101016