Worth a closer look
Evidence key Strong Moderate Weak How we grade
Labeled fragrance allergen (EU) Skin allergen Scent ingredient Oxidizes into stronger allergens
- What it can be used for
- Adds scent and reduces or masks body odor (the functions the EU ingredient database, CosIng, lists for it; a product may use it for any of them)
- CAS number
- 78-70-6
Why it’s flagged
A fragrance allergen the EU requires companies to name on the label.
- Annex III entry 84. Source: EU Cosmetics Regulation, Annex III (restricted)
Must be named on EU labels above 0.001% in leave-on and 0.01% in rinse-off products. Elsewhere, including the US, it can hide inside “fragrance”.
Classified as a skin sensitizer (may cause an allergic skin reaction).
- Skin Sens. 1B (H317). Source: EU CLP Regulation, Annex VI harmonized classification
EU hazard statement H317: may cause an allergic skin reaction.
Used to add scent: its official function is perfuming or fragrance.
- Listed functions: deodorant, perfuming. Source: EU CosIng ingredient database
The EU ingredient database (CosIng) lists this ingredient's function as perfuming or fragrance, so it may be there to add scent, even on a label that never says “fragrance.”
Reacts with air to form stronger skin allergens.
- Forms allergenic hydroperoxides when exposed to air. Source: ihateperfume.com graded evidence
These scent chemicals react with air once a product is opened and form hydroperoxides, which are much stronger skin allergens. See the graded evidence below.
What the research says
- Common scent chemicals such as linalool hardly cause allergy when fresh, but once exposed to air they form new chemicals that do: in 1,511 dermatitis patients at six European clinics, 1.3% were allergic to air-oxidized linalool (later studies with a stronger test found about 7%). Strong evidence. Matura 2005
- Oxidized forms of limonene and linalool, formed when these common fragrance terpenes react with air, are now treated as a standard, distinct fragrance-allergen category in mainstream dermatology, alongside fragrance mix I/II and balsam of Peru. Strong evidence. Aristizabal-Torres 2025
- Among 5,773 people tested for eczema at a Swedish hospital, 9.4% were allergic to the air-oxidized forms of two of the most widely used scent chemicals: linalool (7.0%) and limonene (5.1%). Strong evidence. Sukakul 2022
- A positive patch test for oxidized linalool is not just a lab artifact: patients who test positive also develop real dermatitis from everyday-strength fragranced products used the way a consumer would use them, not only from the strong test doses used in the clinic. Strong evidence. Andersch Björkman 2014
- Limonene and linalool become skin allergens when they react with air: in European dermatitis clinics, 3.9-20% of patients tested reacted to oxidized linalool and 1.4-13.7% to oxidized limonene, against under 1% for the fresh chemicals. Strong evidence. Ogueta 2022
- The two molecules that give lavender oil its scent, linalool and linalyl acetate, were put through the full regulatory endocrine test battery (OECD guideline cell assays plus rat uterotrophic, Hershberger and one-generation reproductive studies) and came back negative on estrogen and androgen endpoints — in a study written, run and entirely funded by BASF, the company that manufactures both chemicals, with all five authors BASF employees. Strong evidence. Hareng 2024 Industry-funded
- Many fragrance chemicals become stronger skin allergens after the bottle is opened: limonene, linalool and geraniol react with air at room temperature to form hydroperoxides that, in mouse tests, sensitize at 5-10 times lower concentrations than the fresh chemical. Strong evidence. Pastor-Nieto 2021 (Karlberg 2013)
- The industry's safety panel cleared linalool, a lavender-scented chemical in most fragranced products, as raising 'no safety concerns' after testing the fresh chemical; independent clinics later found that air-exposed (oxidized) linalool causes allergic reactions in about 7% of patients patch-tested for skin allergy (2,900 patients in 9 centers; 5,773 in Sweden, with rates rising). Strong evidence. Bickers 2003 (RIFM Expert Panel) Industry-funded
About ingredients flagged like this one:
- In a survey of 187 US pediatric personal-care products, preservatives (57.8% of products) were a more common source of contact allergens than fragrance (29.4%), even though the products were being screened specifically for hypoallergenic/fragrance-related marketing claims. Moderate evidence. Hamann 2015
Each finding shows its evidence grade. See every graded fact or how we grade.
Don’t want it on you or in your air? Look for “fragrance-free,” not “unscented.” An unscented product can still contain a masking fragrance. Why the words matter.
What this page can’t tell you
These lists describe what a substance can do, its hazard. The risk from one product depends on how much is in it and how you use it, and the label doesn’t say how much.
Not being on a list doesn’t make an ingredient safe. It may never have been assessed.
“Fragrance” or “parfum” on a label can hide this ingredient and many others. In the US, the individual chemicals in a fragrance are rarely named on the label.
Check your products
Check a whole labelProducts that list itEWG Skin DeepShop fragrance-free
“Products that list it” opens Open Beauty Facts, a free database anyone can edit.
Flagged the same way
Official lists checked September 2026. Spotted a mistake? Tell us.