Every fact on this site, with its evidence grade, its caveats, and a link to the source.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Laws and loopholes / Government agency
Under Australian law (cl. 7(8) of the Consumer Goods (Cosmetics) Information Standard 2020), a cosmetic product's fragrance can be listed on the label simply as "fragrance", "fragrances", "parfum" or "parfums", with no legal requirement to name the individual fragrance ingredients.
Strong evidence: Primary legal text quoted directly; this is the binding rule, not a compliance study of how often companies actually use the generic word versus listing ingredients.
Source: Consumer Goods (Cosmetics) Information Standard 2020 (Cth) Link to this fact
Laws and loopholes / Government agency
Australia's cosmetics-labeling law contains no fragrance-allergen list, threshold, or disclosure requirement of any kind, unlike the EU/UK (Regulation (EU) 2023/1545) or Canada's 2026 mandatory allergen list.
Strong evidence: Based on a full read of the instrument's text; confirms an absence rather than a stated policy choice explained in the text itself.
Source: Consumer Goods (Cosmetics) Information Standard 2020 (Cth) Link to this fact
Laws and loopholes / Government agency
Under New Zealand law (Schedule 1, cl. 1(2)(e) of the Cosmetic Products Group Standard 2020), a cosmetic product's fragrance can be labeled simply as "fragrance", "fragrances", "parfum" or "parfums", with no legal requirement to name the individual fragrance ingredients — wording essentially identical to Australia's rule (for fragrance ingredients other than the named allergens).
Strong evidence.
Caveats
Primary legal text quoted directly. The captured PDF carries a diagonal "DRAFT" watermark on every page despite its internal file title matching EPA's own published "CLEAN" filename; content is self-consistent and matches other sources' citations of this standard, but the watermark itself was not independently resolved. Current consolidated text (in force 1 Jan 2026) revokes the NZ override (Sch 1 cond. 1(6) '[Revoked]'), so 24 of the classic 26 allergens listed in Schedule 5 must now be named above 0.001%/0.01% on a plain reading; other fragrance ingredients can still be labeled 'fragrance'. Textual reading, not confirmed by EPA guidance. See src-2026-nz-epa-cosmetic-products-group-standard-consolidated-current.
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552) Link to this fact
Laws and loopholes / Government agency
New Zealand's 2020 cosmetics standard requires nanomaterial ingredients to be labeled with the word "nano" in brackets and notified to the EPA, a disclosure requirement Australia's contemporaneous 2020 cosmetics standard does not have.
Strong evidence: Primary legal text quoted directly (cl. 1(10) and Part 2 cl. 6).
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552) Link to this fact
Laws and loopholes / Government agency
The cosmetics industry's 2021 safety review of benzophenone-3 (oxybenzone) explicitly covers only its use as a light stabilizer/product-protectant at up to 0.5% concentration — not its use as an active sunscreen ingredient at up to 6%, which is regulated separately by the FDA under 21 CFR 352 and was not included in this safety review's concentration-of-use survey.
Strong evidence: Quoted directly from the industry panel's own report; do not read this report's 'safe' conclusion as covering benzophenone-3's sunscreen-active use.
Source: CIR 2021 Benzophenones Industry-funded Link to this fact
Laws and loopholes / Government agency
US federal regulation (21 CFR 352.10) permits oxybenzone (benzophenone-3) as a sunscreen active ingredient at up to 6 percent.
Strong evidence.
Caveats
Directly quoted from the codified text ("(l) Oxybenzone up to 6 percent"); the whole Part carries its own indefinite-stay notice since 2003-2004, so treat this as the codified ceiling, not necessarily FDA's current live enforcement position.
Source: 21 CFR 352.10 (2023 ed.) Link to this fact
Laws and loopholes / Government agency
21 CFR 352.10 lists 16 permitted OTC sunscreen active ingredients, each with its own maximum concentration: PABA 15%, avobenzone 3%, cinoxate 3%, dioxybenzone 3%, homosalate 15%, menthyl anthranilate 5%, octocrylene 10%, octyl methoxycinnamate 7.5%, octyl salicylate 5%, oxybenzone 6%, padimate O 8%, phenylbenzimidazole sulfonic acid 4%, sulisobenzone 10%, titanium dioxide 25%, trolamine salicylate 12%, and zinc oxide 25%.
Strong evidence: Two paragraph letters, (d) and (g), are reserved (no ingredient assigned).
Source: 21 CFR 352.10 (2023 ed.) Link to this fact
Laws and loopholes / Government agency
A 2002 FDA amendment renamed four sunscreen actives to their now-standard names (menthyl anthranilate to meradimate, octyl methoxycinnamate to octinoxate, octyl salicylate to octisalate, phenylbenzimidazole sulfonic acid to ensulizole) at unchanged concentration limits, but that amendment was itself stayed before its effective date and never took legal effect.
Strong evidence: The pre-2002 names remain the technically operative ones in the 2023 codification even though the newer names are now standard industry usage.
Source: 21 CFR 352.10 (2023 ed.) Link to this fact
Laws and loopholes / Government agency
The entire FDA sunscreen active-ingredient monograph (21 CFR Part 352) has carried an indefinite stay since an effective-date note dated June 4, 2003/2004, as printed in the CFR's own 2023 edition.
Strong evidence.
Caveats
The captured text states only the stay itself; it does not mention the 2019 proposed rule or the 2020 CARES Act OTC monograph reform that are understood (from outside this document) to now govern the monograph's actual reassessment.
Source: 21 CFR Part 352 (2023 ed.) Link to this fact
Laws and loopholes / Government agency
Under FDA's sunscreen combination rule, each active ingredient in a combination sunscreen must independently contribute a minimum SPF of at least 2, and the finished product's minimum labeled SPF must be at least the number of combined actives multiplied by 2.
Strong evidence: Applies only to combinations of actives named in the specific sub-lists cross-referenced in 352.20(a).
Source: 21 CFR 352.20 (2023 ed.) Link to this fact
Laws and loopholes / Government agency
FDA's standard reference sunscreen for validating SPF testing laboratories is an 8-percent homosalate preparation with a defined mean SPF of 4.47 (standard deviation 1.279).
Strong evidence: A laboratory-validation standard, not a claim about homosalate's real-world sun protection performance at that concentration in a finished product.
Source: 21 CFR 352.70 (2023 ed.) Link to this fact
Laws and loopholes / Other evidence
As of the Spring 2025 Unified Agenda, FDA's MoCRA-mandated fragrance-allergen labeling rule (RIN 0910-AI90) was still in "Proposed Rule Stage" with no CFR citation, about ten months past its statutory June 29, 2024 deadline for a proposed rule, and FDA's own projected date for issuing that proposed rule was May 2026.
Strong evidence: Government regulatory-tracking record, not itself a finding; a later edition (captured same batch) shows this self-projected date later slipped further to November 2026.
Source: Unified Agenda, RIN 0910-AI90, Spring 2025 edition, accessed 2026-09-28 Link to this fact
Laws and loopholes / Other evidence
FDA's own MoCRA overview page lists "Fragrance allergen labeling requirements" as one of three regulations MoCRA requires FDA to write, but gives it no date, docket link, RIN, or status of any kind — unlike the adjacent talc-asbestos testing-methods mandate on the same page, which links to a dated proposed rule (December 2024) and its later withdrawal (November 2025), and the PFAS report mandate, which links to a report FDA actually published (December 29, 2025).
Strong evidence.
Caveats
The page's silence on the fragrance-allergen rule does not by itself prove the rule is stalled; its actual tracked status (Proposed Rule Stage, deadline missed, target slipping) comes from FDA's separate Unified Agenda entries, not this page.
Source: FDA MoCRA overview page, accessed 2026-09-28 Link to this fact
Laws and loopholes / Other evidence
Great Britain keeps its own, separately amended copy of the EU cosmetics regulation (Regulation (EC) No 1223/2009) rather than automatically following the EU's current text, confirmed by UK-specific post-Brexit insertions such as Article 5A on Northern Ireland-established responsible persons.
Strong evidence.
Caveats
Confirmed directly from legislation.gov.uk's official contents page (accessed 2026-09-28). This page's table of contents does not itself show whether the fragrance-allergen Annex III specifically has been updated; that is checked instead via UK SI 2026/109.
Source: legislation.gov.uk, Reg. (EC) No 1223/2009 (GB-retained) Link to this fact
Laws and loopholes / Government agency
New Zealand's cosmetics Schedule 5 names the EU's classic 26 fragrance allergens individually, by CAS number, with the same 0.001% (leave-on) / 0.01% (rinse-off) disclosure thresholds the EU uses — but a New Zealand-specific override note then explicitly permits every one of those named substances (plus benzyl alcohol and two restricted musks) to be declared on the label only generically, as "fragrance" or "parfum," instead of by name.
Strong evidence.
Caveats
Verified by reading the full Schedule 5 table and its override note directly in this consolidated (pre-1-January-2026) text. The current (post-2026) version has now been read (src-2026-nz-epa-cosmetic-products-group-standard-consolidated-current): it retains Schedule 5's named-allergen list at the same thresholds (24 of the original 26 entries) but has revoked the override clause this claim describes (Sch. 1, condition 1(6), now "[Revoked]"), with no replacement found. This claim accurately describes the pre-2026 text only; see the current-text page and C355's extension for the current status.
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552, consolidated to 2025) Link to this fact
Laws and loopholes / Other evidence
A cosmetic product's fragrance-allergen labeling can legally differ between Great Britain and Northern Ireland, because Northern Ireland automatically continues to track EU cosmetics rules under the Windsor Framework (Annex 2's general alignment mechanism for placing manufactured goods on the market) while Great Britain runs its own, separately updated regime.
Strong evidence.
Caveats
Official UK government statutory guidance, updated 29 June 2026, checked directly (accessed 2026-09-28). States the general EU-alignment mechanism for NI, not a specific confirmation that any one EU amendment (such as Regulation 2023/1545) has by name reached NI.
Source: OPSS 2026 (GB/NI guidance) Link to this fact
Laws and loopholes / Other evidence
As of September 2026, Great Britain has not adopted the EU's expanded fragrance-allergen labeling list (Commission Regulation (EU) 2023/1545): the most recent identified GB amendment to the cosmetics regulation's restriction annexes (UK SI 2026/109, made 4 February 2026) addresses unrelated CMR substances, ozone, and a hexyl-salicylate concentration cap, and neither adds to the fragrance-allergen declaration list nor references Regulation 2023/1545, while Northern Ireland continues to track EU cosmetics rules generally under the Windsor Framework.
Strong evidence.
Caveats
Based on this SI's full primary text plus the GB/NI split documented in this batch's other two sources; does not rule out an allergen-list change in one of the five earlier GB cosmetics SIs (2022/659, 2023/836, 2024/455, 2024/1334, 2025/413) named in this SI's own footnote but not independently read here. GB's non-adoption is 'as of' this capture (2026-09-28), not a claim about a permanent decision; industry sources describe an OPSS consultation on alignment as only 'expected.'.
Source: UK SI 2026/109 Link to this fact
Laws and loopholes / Other evidence
UK SI 2026/109 adds a new maximum-use-concentration cap (0.001%-2%, by product type and age group) for hexyl salicylate, an ingredient already subject to the separate fragrance-allergen labeling threshold, not a new allergen added to the label-disclosure list.
Strong evidence.
Caveats
Read directly from the SI's Schedule 2 and Explanatory Note (2026-09-28). The concentration cap and the labeling-declaration threshold are two distinct legal mechanisms within the same Annex structure; conflating them would overstate what this SI does.
Source: UK SI 2026/109 Link to this fact
Laws and loopholes / Other evidence
Between the Spring 2025 and 2026 editions of the Unified Agenda, FDA's own self-projected date for its MoCRA fragrance-allergen labeling proposed rule slipped six months, from May 2026 to November 2026, and the rule's "Included in the Regulatory Plan" status changed from "Yes" to "No," with no CFR citation yet assigned in either edition.
Strong evidence: Government regulatory-tracking record comparing two editions of the same RIN; does not itself establish why the target slipped.
Source: Unified Agenda, RIN 0910-AI90, 2026 edition, accessed 2026-09-28 Link to this fact
Laws and loopholes / Other evidence
As of September 2026, more than two years after MoCRA's statutory June 29, 2024 deadline, FDA has not issued a proposed or final rule on cosmetic fragrance-allergen labeling.
Strong evidence: The Federal Register search result is a negative finding (absence of a document), not a citable published statement; phrased here as "as of September 2026" per the capture date.
Source: Unified Agenda, RIN 0910-AI90, 2026 edition, accessed 2026-09-28; federalregister.gov search, accessed 2026-09-28 Link to this fact
Laws and loopholes / Government agency
In 2023, the EU added mandatory individual labeling for 56 more fragrance allergens on cosmetic labels, on top of the 24 already required, bringing the total to roughly 80 — not a jump to 56 total.
Strong evidence: Figure is the Commission's own recital arithmetic (24 + 56); several secondary sources mistakenly describe this as expanding the list 'to 56.'.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
The EU's 56 newly added fragrance allergens were identified by the Scientific Committee on Consumer Safety (SCCS) in a 2012 opinion (SCCS/1459/11), eleven years before the labeling requirement actually took effect.
Strong evidence: The regulation does not reproduce the SCCS opinion's own data tables; the gap between scientific identification (2012) and legal implementation (2023) is itself notable.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
The new EU fragrance-allergen entries are implemented as 45 new Annex III reference numbers (327-371), several of which bundle multiple named plant-oil species or chemical isomers under a single entry number — for example one entry covers 7 named rose species and another covers 4 named lavender/narcissus species.
Strong evidence: Counted directly from the regulation's Annex text, cross-checked against page-image crops of two entries.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
The EU's fragrance-allergen labeling thresholds are unchanged by the 2023 amendment: an individual allergen must be named when it exceeds 0.001% in leave-on cosmetic products or 0.01% in rinse-off products.
Strong evidence: Same thresholds as the original 2003 rule; the amendment only changes which substances they apply to.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
Cosmetics manufacturers had until 31 July 2026 to stop placing non-compliant fragranced products on the EU market, and retailers may continue selling existing non-compliant stock until 31 July 2028.
Strong evidence.
Caveats
Exact dates from the regulation's own footnotes (*1, *2, *4); for 17 updated entries, continued sale in the interim required already complying with the pre-2023 rules as of 15 August 2023.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
The EU's 2023 fragrance-allergen expansion includes many whole essential oils and plant extracts by species, not just synthetic single chemicals — including lavender, rose, bergamot, ylang ylang, clove, sandalwood, patchouli, cedarwood, geranium, and peppermint oils.
Strong evidence: Each named oil/extract is its own Annex III reference number with its own CAS number(s); 'natural' or 'essential oil' products are not exempt from these labeling obligations.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
New Zealand's cosmetics standard, as consolidated and current to 1 January 2026, has revoked the clause that let its EU-style named fragrance allergens be declared only generically as "fragrance" or "parfum": Schedule 1, condition 1(6) now reads "[Revoked]", with no replacement provision found anywhere in the 308-page text.
Strong evidence.
Caveats
Primary legal text, read and grepped in full for the override's operative language, which was not found restated anywhere. This is this ingest's own textual finding, not a labeling change EPA's own regulatory-history description of the amendment names.
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552, consolidated and current to 1 Jan 2026) Link to this fact
Laws and loopholes / Government agency
24 of the EU's original 26 classic fragrance allergens remain individually named in New Zealand's Schedule 5 at the same 0.001% (leave-on) / 0.01% (rinse-off) disclosure thresholds the EU uses; one of the missing two (Lilial, CAS 80-54-6) has been moved to Schedule 4 and banned outright rather than merely restricted.
Strong evidence.
Caveats
Verified by reading Schedule 5's table directly (refs 45, 69-92 still carry the threshold condition; ref 83, Lilial, now reads "Line moved or deleted" and appears instead at Schedule 4 entry #1666).
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552, consolidated and current to 1 Jan 2026) Link to this fact
Laws and loopholes / Government agency
New Zealand's 2026 amendment did not adopt the EU's 2023 expanded fragrance-allergen labeling list (Commission Regulation (EU) 2023/1545, ~56 additional substances); New Zealand's named-allergen disclosure regime remains pinned to the EU's pre-2023 list.
Strong evidence.
Caveats
Confirmed by an exact count: the Schedule 5 individual-disclosure-threshold condition appears exactly 24 times in the document, all within reference numbers 45-92; no entry beyond ref 92 (including methyl eugenol, ref 102, one of the EU's newly added substances) carries it.
Source: Cosmetic Products Group Standard 2020 (NZ, HSR002552, consolidated and current to 1 Jan 2026) Link to this fact
Skin allergy / Review of other studies
EU scientific advisers (SCCS 2012) list 82 fragrance ingredients as established causes of skin allergy in people.
Strong evidence: Cite SCCS 2012 directly; this review is low reliability.
Source: Kumar 2020 (SCCS 2012), Journal of Cosmetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
In 658 Danish/Swedish patients with hand eczema, 67 (10.2%) reacted to fragrance chemicals commonly found in household products, and the standard fragrance-mix patch test alone would have missed more than half of these reactions.
Strong evidence.
Caveats
Clinic-referred hand-eczema population, not the general public. Confirmed directly against the full primary (Heydorn et al. 2003, Contact Dermatitis 48:317-323), not just its PubMed abstract or Kumar 2020's secondary table.
Source: Kumar 2020 (Heydorn 2003), Journal of Cosmetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
The fragrance chemicals most often found in household products were mostly not in the standard fragrance-allergy patch test used at the time: 6 of its 8 chemicals were in 12% of products or fewer.
Strong evidence.
Caveats
Frequency in products is not the same as clinical sensitization rate; FM II and hydroperoxide testing later added. Clinically confirmed in Heydorn et al. 2003 (n=658 hand-eczema patients, 3 centers): only 3 of the 14 chemicals selected from this paper's household-product survey were FM I constituents, and FM I caught only 45.5% of the fragrance-allergic patients (5.6% of all patients tested missed). The exposure-frequency leader, limonene (78% of products), caused only 0.8-0.9% oxidized-limonene reactivity clinically — product frequency of a chemical still does not predict its clinical allergy rate.
Source: Rastogi 2001, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
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.
Caveats
Dermatitis patients, not general population; 2005 test concentration (2.0% pet.) was later shown too low. Clinical relevance no longer just inferred: Andersch Björkman 2014 (ROAT) shows patients identified this way go on to develop dermatitis from twice-daily use of a cream/perfume containing oxidized linalool at concentrations as low as 0.3% (0.056% linalool hydroperoxides, ~27 µg/cm²) — inside the 0.1–2% range measured for individual fragrance ingredients in real products.
Skin allergy / Animal study
Common fragrance chemicals such as limonene (citrus) and linalool (lavender) react with air to form far stronger skin allergens; in mouse tests, oxidized limonene was about 10 times more potent than fresh limonene.
Strong evidence: Mouse LLNA potency; review of replicated data.
Skin allergy / Measured in people or real products
In European skin clinics, 2.8-5.2% of patients tested for dermatitis reacted to oxidized limonene.
Strong evidence: Consecutive dermatitis patients, not general population.
Skin allergy / Measured in people or real products
In patch tests of 2,900 dermatitis patients in six countries, 5.2% were allergic to oxidized limonene and 6.9% to oxidized linalool, two of the most common fragrance chemicals.
Strong evidence: Clinic population, not general public.
Source: Bråred Christensson 2016, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
Fresh limonene and linalool rarely cause allergy (0.1-0.3% of patients); the allergens form when these chemicals react with air, which also happens in essential oils and perfumes during storage.
Strong evidence: Parent-compound rates cited from IVDK/Danish data.
Source: Bråred Christensson 2016, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In 2,900 dermatitis patients tested at nine clinics in Europe, Asia, and Australia, 6.9% were allergic to air-oxidized linalool, the form a common floral scent chemical found in most perfumes, cosmetics, and many cleaners takes after contact with air.
Strong evidence: Dermatitis patients, not general population; 72% weak reactions; range 3-14% by clinic.
Source: Christensson 2012, Contact Dermatitis Link to this fact
Skin allergy / Measured in people or real products
60.5% of patients allergic to oxidized linalool would never have learned they had a fragrance allergy from the standard fragrance patch tests.
Strong evidence: Dermatitis patients.
Source: Christensson 2012, Contact Dermatitis Link to this fact
Skin allergy / Measured in people or real products
80% of patients allergic to oxidized linalool whose products were checked were using fragranced products, mainly shampoos, soaps, and creams.
Strong evidence.
Caveats
Linalool confirmed in their products in 38%; clinical relevance established in 41%. Andersch Björkman 2014 (ROAT), drawn from this same 2,900-patient cohort's Gothenburg patients, causally confirms the exposure-effect link: repeated open application of oxidized-linalool-containing cream/perfume at real-product concentrations (down to 0.3%) reproduced dermatitis, and participants who had already avoided linalool-containing products mostly reported improvement.
Source: Christensson 2012, Contact Dermatitis Link to this fact
Skin allergy / Review of other studies
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: Clinic patients referred for patch testing, not general population.
Skin allergy / Review of other studies
Standard allergy tests with fresh limonene and linalool miss most of these allergies, so European experts now recommend adding the oxidized forms to routine patch testing.
Strong evidence.
Skin allergy / Measured in people or real products
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: Clinic population referred for suspected contact allergy; single center.
Skin allergy / Review of other studies
Scent chemicals such as limonene and linalool rarely cause skin allergy when fresh, but once exposed to air they turn into much stronger allergens; the older the product, the more of them it contains.
Strong evidence: Review of experimental and clinical work; no new data.
Source: Karlberg & Lepoittevin 2021, Contact Dermatitis Link to this fact
Skin allergy / Measured in people or real products
Even the fragrance industry's own safety institute classes the cinnamon-scent chemicals cinnamal and cinnamyl alcohol as human skin sensitizers: in its volunteer tests, 29 of 451 people became allergic to cinnamal at 1% or more.
Strong evidence: Industry-run HRIPT/maximization panels, mostly unpublished RIFM reports; 0/≈200 sensitized at ≤0.5%.
Source: RIFM Expert Panel 2005, Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In people already allergic to cinnamal, a deodorant with just 0.01% of it triggered a reaction in 1 of 9, and 0.032% in 4 of 9; the industry limit is 0.05%, and it was set to prevent new allergies, not reactions in people already sensitized.
Strong evidence.
Caveats
Confirmed by the primary source, now in our evidence base: Bruze et al. 2003, an independent (non-industry, no COI declared), double-blind provocation study with a 20-patient non-allergic control group (0/20 reacted) and P<.001 statistics tying the reaction to both cinnamal-sensitization and the actively-scented axilla. The study's own authors recommend a deodorant limit below 0.01%, stricter than the 0.05% IFRA cap.
Source: RIFM Expert Panel 2005 (citing Bruze 2003), Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
The fragrance industry's own safety review of the rose ketone cis-beta-damascone records that 10 of 50 human volunteers became sensitized when it was patch tested at 5%, and that the test had to be stopped early because of the number of skin reactions.
Strong evidence: 5% is roughly 100x a fine-fragrance use level (max reported 0.02%); at 0.05% two panels gave 0/53 and 0/28.
Source: Lalko 2007 (RIFM), Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
Rose ketones are a real but uncommon allergen: 0.5% of 1606 consecutive European patch-test patients reacted to a 0.2% damascone mixture, and none of 202 Japanese dermatitis patients reacted at 2%.
Strong evidence: Clinic populations, elicitation prevalence not induction risk; original data are Frosch 2002 and Kozuka 1996, reported via the RIFM review.
Source: Lalko 2007 (RIFM), Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
About 1 in 5 people in the general population (20.1% of 20,107 people patch tested in 28 studies) are allergic to at least one common chemical that touches the skin, such as nickel, fragrance, preservatives, or hair dye.
Strong evidence: Meta-analysis, very high heterogeneity (I2 97%); mostly nickel; publication bias detected.
Skin allergy / Measured in people or real products
After nickel, the standard fragrance allergy test (Fragrance Mix I) was the most common positive in the general population: about 3.5% reacted, across 19 studies and 19,440 people.
Strong evidence: Pooled 1966-2017 (CI 2.1-5.4%); the largest modern study found 1.8-2.6% for the same test.
Skin allergy / Review of other studies
The standard fragrance patch test covers only 8 of the 82 fragrance chemicals known to cause allergy in people, so any single test undercounts fragrance allergy.
Strong evidence: Authors' discussion; oxidized limonene/linalool never tested in a general-population sample.
Skin allergy / Measured in people or real products
Among about 4,100 North American patients referred for allergy patch testing in 2019–2020, 12.8% reacted to the standard fragrance mix and 11.1% to oxidized linalool, both among the ten most common skin allergens and both up from 2017–2018.
Strong evidence: Referral population, not the general public; primary is DeKoven 2023 (NACDG), cited by the review.
Skin allergy / Review of other studies
Common fragrance ingredients such as limonene and geraniol turn into stronger skin allergens when they react with air in an opened bottle.
Strong evidence: Review relay only; the numbers come from the primary autoxidation studies on the transformation-products hub.
Source: Khalid & Abdollahi 2021, Iranian Journal of Pharmaceutical Research Link to this fact
Skin allergy / Measured in people or real products
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: Clinic rates are in dermatitis patients, not the general population; test preparations debated; fresh linalool is genuinely a weak sensitizer.
Source: Bickers 2003 (RIFM Expert Panel), Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
Skin allergy / Industry source
The industry once allowed the allergen citral only if mixed with a companion terpene (originally tested at about 20% d-limonene, later mandated at ≥25%), claiming the terpene 'quenched' the allergic reaction; the original 1976 evidence for this was a single unreplicated human test with no subject numbers reported and was already internally inconsistent, later industry HRIPTs could not reproduce quenching for a related aldehyde (cinnamaldehyde), and air-oxidized limonene, the proposed quencher, is itself now one of the commonest fragrance allergens (about 5% of patients tested).
Strong evidence.
Caveats
The failed replication documented in our evidence base is for cinnamaldehyde + eugenol/limonene, not citral + limonene itself; IFRA's formal withdrawal of the quenching rule is not documented in our evidence base. The founding 1976 test (Opdyke) also showed the effect failing at a different ratio of the same ingredients (cinnamic aldehyde:eugenol 2.5:1 sensitized where 1:1 had not), and its own essential-oil control (cinnamon bark oil) itself sensitized, contradicting the paper's own summary.
Source: Ford 1994 (RIFM) Industry-funded Link to this fact
Skin allergy / Animal study
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: Potency from mouse LLNA; cite Karlberg 2013 as primary; clinic data (Bråred Christensson, Sukakul) confirm oxidized forms are common human allergens.
Source: Pastor-Nieto 2021 (Karlberg 2013), Current Treatment Options in Allergy Link to this fact
Skin allergy / Lab study (cells or chemistry)
Chemicals that only become allergens after they are changed by air or by the skin's own enzymes are the worst-predicted group in the industry's own analysis (4.5- to 6.5-fold error, versus about 2-fold for directly reactive chemicals), because the dish assays cannot oxidize or metabolize anything.
Strong evidence: N=32 chemicals in the worst domain; TIMES-software-assigned mechanistic class, not exhaustively confirmed in vivo.
Source: Natsch 2015, Toxicological Sciences Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In a double-blind study, deodorants containing as little as 0.01% cinnamic aldehyde (cinnamal) triggered allergic skin reactions within weeks in people already allergic to it, while an identical unscented deodorant on the other armpit, and the same deodorants used by 20 non-allergic people, caused no reactions.
Strong evidence.
Caveats
Small cohort (9 sensitized test patients, double-blind arm), but statistically significant (P<.001) with a concurrent negative control group and randomized/blinded contralateral-axilla design.
Source: Bruze et al. 2003, Journal of the American Academy of Dermatology Link to this fact
Skin allergy / Measured in people or real products
For people already allergic to oxidized linalool (the air-exposed form of a common floral fragrance chemical), using a scented cream or perfume containing it at concentrations similar to real products (as low as 0.3% oxidized linalool, 0.056% linalool hydroperoxides) was enough to trigger eczema within three weeks of twice-daily use in a repeated-use trial.
Strong evidence.
Caveats
Small N (6 completers); participants were pre-selected as already patch-test-positive, not a general-population sample; lowest concentration tested (0.1% in perfume) did not produce a formal positive.
Source: Andersch Björkman 2014, Contact Dermatitis Link to this fact
Skin allergy / Measured in people or real products
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: No irritant reactions occurred in vehicle controls, so the effect is allergic rather than irritant; the reverse case (a general population screen) was not tested here.
Source: Andersch Björkman 2014, Contact Dermatitis Link to this fact
Information, not medical advice. See also: myths we won’t tell you.