Worth a closer look
Evidence key Strong Moderate Weak How we grade
Labeled fragrance allergen (EU) Scent ingredient Limited by IFRA
- What it can be used for
- Adds scent (the functions the EU ingredient database, CosIng, lists for it; a product may use it for any of them)
- CAS number
- 107-75-5
Why it’s flagged
A fragrance allergen the EU requires companies to name on the label.
- Annex III entry 72. 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”.
Used to add scent: its official function is perfuming or fragrance.
- Listed functions: 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.”
Use limited by the fragrance industry's own IFRA standard.
- IFRA standard “Hydroxycitronellal”: use limited. Source: IFRA Standards Library
IFRA, the fragrance industry's own standards body, sets maximum amounts for this material in different kinds of products.
What the research says
- Seal of Acceptance products must also exclude a named 34-ingredient Ecz-clusion List (including cinnamic alcohol, cinnamic aldehyde, coumarin, eugenol, farnesol, geraniol, hydroxycitronellal, isoeugenol, oak moss absolute and several citrus extracts), chemical UV absorbers other than titanium/zinc/iron physical sunscreens, and formaldehyde releasers, in any amount. Strong evidence. NEA 2026
- Concentrations of hydroxycitronellal found in some 'natural' perfumes (up to 6.04%) exceeded the concentration shown to sensitize 36% of healthy volunteers in repeated-insult patch testing (5%), and were also well above the fragrance industry's own 1996 recommended maximum (equivalent to about 1% in the finished product). Moderate evidence. Rastogi 1996
- In a 1996 Danish GC-MS analysis, 91% (20 of 22) of perfumes marketed as based on natural ingredients contained 1 to 7 of 11 well-known fragrance sensitizers at concentrations up to 7.7%, including one perfume with 6.04% hydroxycitronellal — above the concentration shown to sensitize 36% of healthy volunteers in patch testing. Moderate evidence. Rastogi 1996
- People with chronic, treatment-resistant hand eczema and a history of reacting to scented products can ask their dermatologist for patch testing beyond the standard fragrance mix, including citral, Lyral, hydroxycitronellal and oxidized limonene/linalool. Moderate evidence. Heydorn 2003 Industry-funded
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
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Flagged the same way
Official lists checked September 2026. Spotted a mistake? Tell us.