Evidence for chemical and cellula…ormaldehyde release.

Bronopol, a common preservative, causes skin irritation through multiple mechanisms—not just from the formaldehyde it releases. When bronopol breaks down in your skin, it creates other reactive compounds (like 2-bromoethanol) that trigger immune responses at much lower doses than formaldehyde alone would. This means some people might react to bronopol even if they're not sensitive to formaldehyde.