Fragrance allergen

Farnesol

Farnesol is a sesquiterpene alcohol with a soft green-floral scent, often compared to lily of the valley and linden blossom. It turns up at low levels in many essential oils and is also made from nerolidol. Perfumers use it for lily-of-the-valley effects and as a fixative.

Formula: C₁₅H₂₆O
Molar mass: 222.37 g/mol
CAS: 4602-84-0

Where it comes from

Farnesol has been reported in more than 30 essential oils, usually at low levels of 0.5 to 1.0 per cent, with cabreuva oil holding up to 2.5 per cent. It appears in citronella, neroli, tuberose, rose, ylang-ylang and ambrette seed. Synthetic farnesol, made from nerolidol, has largely replaced extraction from plants.

Smell and use

Mild and delicate: a fresh, green floral note with a lily-of-the-valley character and a sweet linden-flower quality. The odour is low in strength but long lasting, and one source says it seems stronger as it evaporates.

Perfumers reach for farnesol to build lily-of-the-valley notes and to add a fruity nuance, and it also acts as a fixative. It is used in rose and other floral compositions. Beyond perfume it is listed as a flavouring agent in foods and beverages.

On the label

Named on 30% of the 6,851 perfume ingredient lists we hold (2,023 perfumes).

EU: Annex III, entry 82. 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 II, a standard skin-clinic panel.

The SCCS opinion SCCS/1459/11 lists farnesol among its List B fragrance chemicals, and farnesol is one of the six components of Fragrance Mix II, a European patch-test screen. IFRA has a Restriction Standard (Amendment 49) with category limits and a purity specification of at least 96 per cent farnesol isomers. Most company reports summarised by PubChem give the classification '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 31% of 4,889
Eau de toilette 21% of 1,227
Extrait 36% of 341
Parfum 40% of 194
Cologne 35% of 114
Body spray 21% of 42
Other 19% of 27

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

Named alongside

Initio Parfums Privés

Acquired

Common questions

What does farnesol smell like?

Farnesol has a mild, delicate green-floral scent with a typical lily-of-the-valley character. Other descriptions mention fresh, sweet linden flower and an angelica-like tone. It is not a loud material, but it lasts.

Is farnesol natural or synthetic?

It is both. Farnesol occurs in neroli and ylang-ylang oils and in ambrette seeds, and it can be extracted from ambrette seed absolute. Today synthetic farnesol, made from nerolidol, mostly replaces that extraction.

Why is farnesol on my perfume label?

Farnesol is on the EU list of fragrance allergens that must be named in the ingredient list when they exceed set thresholds. For leave-on products such as perfume that threshold is 0.001 per cent of the finished product.