Farnesol
trans,trans-Farnesol
What it is
A natural sesquiterpene alcohol found in rose, neroli, jasmine, and citronella oils, used both as a delicate floral note and as a deodorant active that slows odor-causing bacteria.
In this product: Fragrance and, in deodorants, a mild antibacterial. Adds soft floral character and rounds out other notes.
Dose & route, what actually matters
Allergic contact dermatitis from leave-on skin exposure in sensitised people. For most users at normal concentrations it is well tolerated.
EUROPEAN UNION
Annex III declarable fragrance allergen (one of the original 24 in Regulation 1223/2009), reaffirmed by Commission Regulation (EU) 2023/1545. Named on EU labels above 0.001% leave-on / 0.01% rinse-off.
UNITED STATES
No restriction. Inside “Fragrance” unless disclosed.
The evidence
Farnesol is one of the original 24 EU Annex III fragrance allergens (Regulation 1223/2009) requiring label declaration, reaffirmed by Commission Regulation (EU) 2023/1545.
regulatory · 2023 · source
SCCS opinion SCCS/1459/11 confirmed farnesol remains a relevant established contact allergen among the declarable set.
regulatory · 2012 · source
California Prop 65: Not listed.
How to avoid it
Look for “farnesol” on EU labels. It is also a natural component of many botanical and “clean” fragrance blends, so natural sourcing does not lower the risk for sensitised skin.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.