Fragrance allergen names on ingredient labels

Why one page for seven names

We work from documents; we have not tested any products. People who react to fragrance are often told to check labels for named substances, and the names are scattered across regulations, patch-test lists and chemistry databases. This page puts seven of them side by side: citronellol, geraniol, coumarin, eugenol, benzyl salicylate, hexyl cinnamal and benzyl alcohol. It is a reading guide to what our sources say, not a list of things to avoid.

Fragrance ingredients are not inherently harmful. The issue is what labels mean for people who react to them. Two companion pages cover the other substances most often named in this literature, linalool and limonene, and our page on the EU list of 26 fragrance allergens covers the regulation in more depth.

How to use this page

Each section below follows the same order: identity from PubChem, then what PubMed abstracts and other sources report, then a line on what we found no source for. Findings are attributed (“one study reports”) because an abstract is one study, not a settled fact. Studies of patch-tested patients describe people who were already being investigated for dermatitis, so they are not rates for the general public.

On names: where PubChem lists synonyms we quote them as PubChem synonyms, and we do not say which name any label uses. If you are comparing a label to this page, read the maker’s published list, then use the synonym lists to see whether a word you do not recognise is one of the same substance. How “parfum” and “aroma” fit in is explained in what is parfum and how to read an ingredient list.

Citronellol

Identity. PubChem (US National Library of Medicine, compound 8842) lists CAS numbers 106-22-9 and 26489-01-0 and the synonyms “Citronellol; 3,7-Dimethyloct-6-en-1-ol; Cephrol; 3,7-DIMETHYL-6-OCTEN-1-OL; Elenol; Rodinol; 2,3-Dihydrogeraniol”. It describes citronellol as “a monoterpenoid that is oct-6-ene substituted by a hydroxy group at position 1 and methyl groups at positions 3 and 7”, with a role as a plant metabolite, and notes it as “alcohol form of citronellal; found in rose oil”.

Where it sits in allergy testing. A PMC review says fragrance mix II was introduced in 2005 and contains citronellol at 0.5%, alongside citral, coumarin, hydroxyisohexyl 3-cyclohexene carboxaldehyde, farnesol and alpha-hexyl-cinnamal, at 14% total in petrolatum. DermNet’s baseline series page lists “Fragrance mix II (lyral, citral, farnesol, citronellol, hexyl cinnamic aldehyde, coumarin)”.

What studies report. One study (PubMed abstract, PMID 35671905, Food and Chemical Toxicology 2022) says citronellol is “one of the most used fragrance compounds worldwide”, that “pure citronellol is non-allergenic”, and that the main issue is that it autoxidizes when exposed to air and then becomes allergenic. A second study (PMID 32638395, Contact Dermatitis 2020) patch tested 658 dermatitis patients and reports positive reactions in 0.15%-0.31% of patients for purified citronellol and 0.61%-4.5% for oxidized citronellol. It concludes that oxidized citronellol detects more cases than purified citronellol, and that these cases are not all detected using fragrance mix II. A survey of household detergent labels (PMID 29940212, Regulatory Toxicology and Pharmacology 2018) reports that citronellol and linalool were among the pairs that co-occurred most often together in products.

What we found no source for. The label name citronellol takes in a particular product; whether a given product’s citronellol has oxidised; and any legal limit on it.

Geraniol

Identity. PubChem (compound 637566) lists CAS numbers 106-24-1 and 624-15-7 and the synonyms “GERANIOL; Geranyl alcohol; Lemonol; trans-Geraniol; (E)-3,7-Dimethylocta-2,6-dien-1-ol; (E)-Geraniol; beta-Geraniol”. It describes geraniol as “a colorless to pale yellow oily liquid with a sweet rose odor” and “a monoterpenoid” with a role as “a volatile oil component, a fragrance, an allergen and a plant metabolite”. PubChem’s text says it is found within essential oils including rose oil, citronella, lemongrass and lavender, and “is commonly used by the food, fragrance, and cosmetic industry”. It also says “Sensitivity to geraniol may be identified with a clinical patch test.”

Where it sits in allergy testing. The PMC review gives fragrance mix I as a 1% mixture of seven synthetic substances including geraniol and eugenol, plus oak moss, and DermNet lists geraniol in fragrance mix I. The same review says that in animal experiments the oxidation products of terpenes including geraniol were markedly more allergenic than the unoxidised raw substances, and notes that geraniol can be activated both outside the body (a prehapten) and in the skin (a prohapten).

What studies report. One study (PMID 23510343, Contact Dermatitis 2013) patch tested 655 patients and reports positive reactions in 0.15-1.1% for pure geraniol and 0.92-4.6% for oxidized geraniol, adding that oxidized geraniol detects more patients but that testing only oxidized geraniol does not detect all. Another (PMID 31566752, Contact Dermatitis 2020; 1476 patients) says geranial and neral, found in autoxidation of geraniol, gave 3.4% and 1.9% positive reactions, and that “patch testing with pure geraniol was shown to be of little value”. A Spanish retrospective study (PMID 20573166, 2010) reports geraniol was the allergen most frequently found in the 86 patients tested with a fragrance series. A case report (PMID 20646673, Dermatitis 2010) describes a bartender allergic to lime peel whose reaction was to geraniol, “a minor component of the peel oil”. A review on patch testing (PMC11334351) reports that among massage therapists tested with individual ingredients, citral, isoeugenol and geraniol ranked as the most prevalent causes of contact allergy.

What we found no source for. The label name geraniol takes; how common geraniol allergy is in the general population; and which products contain it.

Coumarin

Identity. PubChem (compound 323) lists CAS numbers 91-64-5 and 103802-83-1 and the synonyms “coumarin; 2H-Chromen-2-one; 2H-1-Benzopyran-2-one; cumarin; 1,2-Benzopyrone; chromen-2-one; Tonka bean camphor”. It describes “colorless crystals, flakes or colorless to white powder with a pleasant fragrant vanilla odor”, “a chromenone having the keto group located at the 2-position”, and a role as “a fluorescent dye, a plant metabolite and a human metabolite”. Its text says coumarin occurs naturally in many plants, spices and foods, including tonka bean, cinnamon, lavender and green tea, and is “used as an additive in perfumes and fragranced consumer products at concentrations ranging from <0.5% to 6.4% in fine fragrances to <0.01% in detergents”.

Where it sits in allergy testing. Coumarin is in fragrance mix II, at 2.5% according to the PMC review, and DermNet lists it in the same mix.

What studies report. The evidence conflicts. A mouse study (PMID 17988284, Contact Dermatitis 2007) says there is “controversy as to whether coumarin… is a contact allergen”, reports that coumarin of purity above 99.9% produced no T-cell activation or allergic response, and concludes that pure coumarin has very weak sensitizing capacities, if any, and that contaminants may account for earlier reports. By contrast, a prospective study (PMID 35690165, JAAD 2022; 291 patients) reports that immediate patch reactions to benzyl alcohol, sorbic acid and coumarin were more frequently observed than standard patch test reactions. The household detergent survey (PMID 29940212) says the fragrance allergens co-occurring together most frequently within households were eugenol, coumarin and cinnamyl alcohol.

What we found no source for. Which of the PubChem synonyms a label would use, and how much coumarin any product contains beyond the ranges PubChem quotes.

Eugenol

Identity. PubChem (compound 3314) lists CAS 97-53-0 and the synonyms “eugenol; 4-Allyl-2-methoxyphenol; 4-Allylguaiacol; Eugenic acid; Allylguaiacol; Caryophyllic acid; p-Eugenol; 2-Methoxy-4-prop-2-enylphenol”. It describes “clear colorless pale yellow or amber-colored liquid” with an “odor of cloves”, and “a phenylpropanoid formally derived from guaiacol”, a major component of clove essential oil. Its text lists eugenol as found in cinnamon, clove and bay leaves, and says it is used in perfumeries, flavorings, essential oils and in medicine. PubChem also gives it the role “a sensitiser” and “an allergen” and calls it “a Standardized Chemical Allergen”.

Where it sits in allergy testing. DermNet lists eugenol in fragrance mix I, separately from isoeugenol, and the PMC review lists it among the seven synthetic substances of that mix. DermNet’s fragrance page says a positive patch to the mix “indicates that you are allergic to one or more fragrance chemicals”, so a positive does not point to eugenol alone.

What studies report. One study (PMID 34414573, Contact Dermatitis 2021) reports that in patients photoallergic to ketoprofen, contact allergy to eugenol was more prevalent than to isoeugenol (23.3% vs 6.7%), while in the dermatitis group the relationship was the opposite (0.4% vs 0.9%). The detergent survey (PMID 29940212) reports eugenol among the substances that co-occurred most often within households.

What we found no source for. The label name used for eugenol, and how many people in the general population react to it alone.

Benzyl salicylate

Identity. PubChem (compound 8363) lists CAS 118-58-1 and the synonyms “BENZYL SALICYLATE; Benzyl 2-hydroxybenzoate; Benzyl o-hydroxybenzoate; Salicylic Acid Benzyl Ester; Phenylmethyl 2-hydroxybenzoate; FEMA No. 2151”. It describes “a colorless liquid” as “a member of phenols and a benzoate ester”, functionally related to salicylic acid.

What PubChem quotes on safety. PubChem reproduces a statement that “the CIR Expert Panel concluded that Benzyl Salicylate is safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating and non-sensitizing, which may be based on a quantitative risk assessment (QRA).” That is the panel’s conclusion as quoted by PubChem, with its conditions, and we do not add to it.

What studies report. The household detergent survey (PMID 29940212) says benzyl salicylate “was used frequently in all-purpose cleaners”. A study of 36 patients with frontal fibrosing alopecia (PMID 33351203, Contact Dermatitis 2021) reports benzyl salicylate among the most frequently positive patch-test allergens (22%) and that it was likely relevant to the dermatitis, but its authors only “speculate” about a relationship with the alopecia. A worldwide multicenter study (PMID 8796746, 1996; 167 subjects) reports that allergy to benzyl salicylate was more common in Japan than in Europe or the United States, and that in Asian patients it was a more frequent allergen. A laboratory study (PMID 30325045, Journal of Applied Toxicology 2019) reports that after forced degradation benzyl salicylate was found unreactive in both peptide-reactivity assays used.

What we found no source for. The label name; where it appears in products other than the all-purpose cleaners one survey names; and the relationship of the alopecia finding to cause, which the authors themselves call a speculation.

Hexyl cinnamal

Identity. PubChem (compound 1550884) is titled alpha-hexylcinnamaldehyde and lists CAS 101-86-0. Its synonyms include “(2E)-2-benzylideneoctanal; 2-Benzylideneoctanal; alpha-Hexylcinnamic aldehyde; alpha-Hexylcinnamyl aldehyde; alpha-Hexyl-beta-phenylacrolein; FEMA No. 2569”. It describes the substance as “a member of the class of cinnamaldehydes carrying a hexyl substituent at the alpha-position” and, in another entry, “a commercially-available skin sensitizer”. Different sources in our set write the name differently: the PMC review says “alpha-hexyl-cinnamal”, DermNet says “hexyl cinnamic aldehyde”, and the PubMed abstracts say “hexyl cinnamal” and “alpha-hexyl cinnamal”. We found no source that states which spelling a label uses.

Where it sits in allergy testing. The PMC review gives alpha-hexyl-cinnamal as the largest share of fragrance mix II at 5%, and a 2008 recommendation paper (PMID 18279149, Contact Dermatitis) names it among the components of fragrance mix 2 recommended for the European baseline series.

What studies report. The detergent survey (PMID 29940212) says the 26 labelled substances were named most often as limonene, linalool and hexyl cinnamal. A 2026 label review of 245 cosmetic and household cleaning products in Turkey (PMID 42324175, Contact Dermatitis) likewise reports linalool, limonene and hexyl cinnamal as the most frequent fragrance substances. The laboratory study (PMID 30325045) reports hexyl cinnamal unreactive in both peptide-reactivity assays after forced degradation. We include that without drawing a conclusion: it is a chemistry result, not a statement about people.

What we found no source for. Which synonym a label uses, and its individual rate of contact allergy, since the sources give figures for the mix as a whole.

Benzyl alcohol

Identity. PubChem (compound 244) lists CAS numbers including 100-51-6 and the synonyms “benzyl alcohol; phenylmethanol; benzenemethanol; phenylcarbinol; Benzenecarbinol; Hydroxytoluene; Benzoyl alcohol; alpha-Toluenol; Phenylmethyl alcohol”. It describes “a clear colorless liquid with a pleasant odor” that “may irritate skin, eyes, and mucous membranes”, and “an aromatic alcohol” with roles as “an antioxidant, a metabolite, a solvent and a fragrance”, used “in perfumery and flavoring”. Several of its listed uses are medical, which is outside this page.

What studies report, and where they disagree. The sources differ in tone. An IVDK analysis (PMID 35080274, JEADV 2022) describes benzyl alcohol as “a widely used preservative, solvent and fragrance material” and a rare sensitizer: of 70,867 patients patch tested, 146 (0.21%) reacted, 89% only weakly, and it concludes benzyl alcohol “cannot be regarded as a significant contact allergen”. A North American analysis (PMID 33579596, JAAD 2021; 50,799 patients) lists benzyl alcohol 1% in petrolatum among the preservatives with the lowest positive rates (0.3%). A 2026 article (PMID 42955808, Cutis) calls it “an underrecognized contact allergen” and says the American Contact Dermatitis Society named it the 2026 Allergen of the Year. The same article says it “can be present in products marketed as ‘clean,’ ‘sensitive,’ ‘fragrance-free,’ or ‘hypoallergenic’ due to current labeling regulations”, and that when used as a fragrance it “may be omitted from the visible ingredient list under US Food and Drug Administration regulations that protect proprietary fragrance formulas as trade secrets.” The prospective study (PMID 35690165) reports immediate reactions to benzyl alcohol more frequently than standard patch-test reactions.

Our guide to FDA fragrance labeling covers the trade-secret rule, and our pages on fragrance-free versus unscented cover what the words on a front label mean.

What we found no source for. Whether benzyl alcohol on a given label is there as preservative, solvent or fragrance; no source we hold lets us tell from a list.

What the EU labelling text says

Commission Regulation (EU) 2023/1545 amends Regulation (EC) No 1223/2009 on labelling of fragrance allergens in cosmetic products. Its recitals say perfume and aromatic compositions are to be referred to by the terms “parfum” or “aroma” in the list of ingredients, complemented by substances required under the “Other” column of Annex III, and that 24 fragrance allergens were then individually labelled. They say the SCCS identified 56 additional fragrance allergens “which have clearly caused allergies in humans”, and that an obligation to label them individually should be introduced “when their concentration exceeds 0,001 % in leave-on products and 0,01 % in rinse-off products”. They add that substances such as prehaptens and prohaptens that can be transformed to known contact allergens by air oxidation or bioactivation “should be treated as equivalent to fragrance allergens”. The transition periods are given as 3 and 5 years.

Here is the limit of what we hold: our copy of the regulation includes the recitals and the line “Annex III to Regulation (EC) No 1223/2009 is amended as follows”, but not the Annex entries. We therefore do not say which of citronellol, geraniol, coumarin, eugenol, benzyl salicylate, hexyl cinnamal or benzyl alcohol appear in the list, and we do not give EU names for them. See the EU 26 page for what we could confirm. For the US, the FDA’s Fragrances in Cosmetics page says that “under U.S. regulations, fragrance and flavor ingredients can be listed simply as ‘Fragrance’ or ‘Flavor.’”

How this site’s watch list works

This part is ours, and it is not a regulation. When we check a product, we read the maker’s published ingredient list. Our fragrance-free test is whether that list shows fragrance, parfum, aroma, perfume, essential oils or fragrance chemicals. Our watch list of named fragrance substances is a tool we use for the last category: a product whose maker list names one of these substances, or others such as linalool and limonene, is flagged. The watch list is our own, built from the patch-test lists above, and no regulator wrote it. Two limits follow. A product that says only “parfum” or “fragrance” is already outside our fragrance-free test, so the watch list adds nothing there. And a label that lists none of the names does not prove none is present, because of the trade-secret rule above.

What we don’t fully know

We found no source for any substance’s name as it appears on labels, and we did not retrieve the Annex of the EU regulation. The PubMed material on this page consists of abstracts, which we quote as abstracts; we did not read full papers. Findings conflict for coumarin and benzyl alcohol. We do not know how much of each substance is in any product. For questions about your own skin, ask a clinician or an allergy or dermatology society.