Eugenol
4-Allyl-2-methoxyphenol · clove note
What it is
The main aromatic compound in clove oil, also in cinnamon and bay leaf. Natural, widely used in perfume and even in dentistry, and a well-documented contact allergen.
In this product: Fragrance. Supplies a warm, spicy, clove-type note.
Dose & route, what actually matters
The harm is allergic contact dermatitis in already-sensitised people from leave-on skin exposure. For the general population at normal use it is not a systemic hazard. Honest framing matters here.
EUROPEAN UNION
Annex III declarable fragrance allergen. Must be named on the label above 0.001% leave-on / 0.01% rinse-off, reaffirmed by Commission Regulation (EU) 2023/1545. Classified Skin Sens. 1B under GHS.
UNITED STATES
No federal restriction. California's 2020 Right-to-Know Act requires reporting at the same thresholds as the EU. Otherwise hides under “Fragrance.”
The evidence
In contact-dermatitis patch testing, eugenol was positive in 55.4% (87 of 157) of fragrance-mix-sensitised patients tested individually.
human · 2000 · source
Eugenol is an EU Annex III fragrance allergen requiring label declaration above 0.001% leave-on / 0.01% rinse-off, reaffirmed by Commission Regulation (EU) 2023/1545.
regulatory · 2023 · source
California Prop 65: Not listed.
How to avoid it
Read the full list, eugenol is named on EU labels above threshold. Note it occurs naturally in clove, cinnamon, and ylang-ylang oils, so “natural” fragrance is not automatically safe 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.