Citronellol

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

106-22-9, 26489-01-0, 7540-51-4, 1117-61-9

Why it’s flagged

• A fragrance allergen the EU requires companies to name on the label.

  • Annex III entry 86. 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 “Citronellol”: 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

• In a rat model of Parkinson's disease, oral citronellol (25 mg/kg/day) given as a month-long pretreatment before each day's dose of the neurotoxin rotenone reduced brain oxidative stress, inflammatory cytokines, glial activation and the loss of dopamine-producing neurons. Moderate evidence. Jayaraj 2022
• The researchers report that citronellol content varies up to 1000-fold within the same product category, which they attribute to the absence of regulation of fragrance content in household products. Moderate evidence. Kim 2024
• A lab analysis of 59 soaps, surface cleaners, laundry and dish-washing products from four European countries found the citrus-scent chemical limonene in 78% of them, linalool in 61% and citronellol in 47%; all three are fragrance chemicals linked to skin allergy. Moderate evidence. Rastogi 2001 Industry-funded
• Citronellol is treated as safe by default – GRAS at the US FDA, a 'non-toxic' biopesticide at the US EPA, and limited only by the fragrance industry's own voluntary IFRA standard – yet this government-funded study found it is brain-penetrant and calls for its content in consumer products to be regulated. Moderate evidence. Kim 2024
• Citronellol, a rose-scented fragrance ingredient present in about half of household products, crosses the blood-brain barrier: brain-to-blood ratios were 0.5-0.8 in fish, up to 0.6 in mice, and 0.77 in a laboratory barrier built from human brain cells. Moderate evidence. Kim 2024
• At high doses in zebrafish and mice, citronellol pushed tryptophan metabolism toward 3-hydroxykynurenine, a neurotoxic metabolite, and produced brain inflammation, roughly double the oxidative stress, a five-fold rise in dying brain cells, a leaky blood-brain barrier and anxiety-like behavior. Moderate evidence. Kim 2024
• The vapor from a single cologne contained at least twenty identifiable chemicals – limonene, linalool, linalyl acetate, alpha- and beta-pinene, terpinolene, citronellol, anethole, coumarin, diethyl phthalate among them – none of which appear on the label. Moderate evidence. Anderson & Anderson 1998

Each finding shows its evidence grade. See every graded fact or how we grade.

Check your products

Check a whole labelProducts that list itEWG Skin DeepShop fragrance-free

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Flagged the same way

• Limonene
• Linalool
• Geraniol
• Hexyl Cinnamal
• Benzyl Alcohol
• Benzyl Salicylate

Official lists checked September 2026. Spotted a mistake? Tell us.