Worth a closer look
Evidence key Strong Moderate Weak How we grade
Labeled fragrance allergen (EU) Limited by IFRA
- What it can be used for
- Adds scent and conditions skin (the functions the EU ingredient database, CosIng, lists for it; a product may use it for any of them)
- CAS number
- 127-51-5
Why it’s flagged
A fragrance allergen the EU requires companies to name on the label.
- Annex III entry 90. 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”.
Use limited by the fragrance industry's own IFRA standard.
- IFRA standard “Methyl ionone, mixed isomers”: 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
- Sanitary pads, panty liners and tampons can contain undisclosed fragrance allergens — chiefly alpha-isomethyl ionone (in every scented tampon tested), hexyl cinnamal and benzyl salicylate, plus trace limonene, linalool and geraniol — and in the EU they do not have to declare any of them. Strong evidence. Pastor-Nieto 2021 (Desmedt 2020)
- A violet-water cologne that doctors reported as a lavender-oil exposure in a boy with breast growth declared no essential oil on its ingredient list, and an essential-oil industry group's lab analysis found none; it reported a synthetic fragrance allergen (alpha-isomethyl ionone), azo dyes and diethyl phthalate instead. Go by the ingredient list of the actual product, not its scent name. Moderate evidence. Braunstein & Braunstein 2023 Industry-funded
- In one of the best-known reports linking 'lavender' products to breast growth in children, the boy's violet-water cologne declared no essential oil on its ingredient list; the essential-oil industry's own analysis found none, but reported a synthetic fragrance allergen (alpha-isomethyl ionone), azo dyes and diethyl phthalate, a fragrance solvent suspected of hormone disruption. Moderate evidence. Giroux & Orjubin 2020 (JCEM letter; Consortium Huiles Essentielles) 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
“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.