Fragrance allergen

Isoeugenol

Isoeugenol is an isomer of eugenol with a spicy, clove-like scent and a carnation-like edge. It occurs in ylang-ylang and clove oils and can be made from eugenol. Perfumers use it in carnation, spicy and ambery notes. It is one of the older named fragrance allergens.

Where it comes from

PubChem says isoeugenol occurs in ylang-ylang oil and other essential oils. ScenTree puts it at about 1% in clove bud oil and up to 0.5% in ylang-ylang fractions, and says it can be produced from eugenol by isomerisation. The SCCS reports cis and trans forms, with the trans form making up 82 to 88% of trade products.

Smell and use

Spicy and clove-like, with a floral, carnation-like character. HSDB records a spice-clove odour, and JECFA describes a floral, carnation-like aroma.

HSDB says isoeugenol is used in perfumery in a large number of blossom compositions, mostly for clove and carnation types but also in oriental perfumes. ScenTree lists carnation, spicy and ambery notes, often combined with eugenol, and says vanillin was once produced from it.

On the label

Named on 27% of the 6,851 perfume ingredient lists we hold (1,855 perfumes).

Also filed as
(E)-2-methoxy-4-(prop-1-enyl)phenol, (Z)-2-methoxy-4-(prop-1-enyl)phenol
EU
Annex III, entry 73. Must be named above 0.001% in leave-on products (0.01% rinse-off).
Great Britain
Required, same thresholds. GB Annex III
Patch tests
In Fragrance Mix I, a standard skin-clinic panel.

Isoeugenol is named in Great Britain's Annex III and has long been on the EU list: it must be listed above 0.001% in leave-on or 0.01% in rinse-off products. SCCS/1459/11 (2012) places it in its +++ band (101 to 1000 reported positive reactions). IFRA's index lists a Restriction standard (2020). In PubChem's summary of ECHA company reports, 99.7% say it may cause an allergic skin reaction.

A list that does not name it does not prove it is absent: brands only have to name it above the threshold.

Frequency by concentration

  • Eau de parfum 28% of 4,889
  • Eau de toilette 22% of 1,227
  • Extrait 27% of 341
  • Parfum 35% of 194
  • Cologne 29% of 114
  • Body spray 7% of 42
  • Other 19% of 27

Share of the perfumes we hold a list for, in each concentration.

Named alongside

Share of the lists naming Isoeugenol that also name each of these.

Perfumes whose box names it

Common questions

What does isoeugenol smell like?

Spicy and clove-like, with a floral, carnation-like side. HSDB records a spice-clove odour, and JECFA describes a floral, carnation-like aroma.

Is isoeugenol the same as eugenol?

No. It is an isomer: PubChem says the allyl group of eugenol is replaced by a prop-1-enyl group. ScenTree says eugenol smells less fruity but more woody and vanillic.

Why is isoeugenol on my perfume label?

It is one of the older named fragrance allergens in both the EU and Great Britain. It must be listed once it passes 0.001% in a leave-on product or 0.01% in a rinse-off product.