Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
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.
The industry / Lab study (cells or chemistry)
The fragrance industry's own data show its main explanation for how fragrance chemicals cause allergy doesn't cover most of them: 34 of 62 ingredients (55%) sensitize despite having no predicted protein-binding alert.
Moderate evidence.
Caveats
Structural-alert software limitation; metabolic activation explains some. Roberts & Api 2018 (different 57-chemical fragrance dataset, no direct overlap confirmed with this claim's 62-chemical set) adds two further indirect-activation routes the alert software here evidently does not capture — slow autoxidation of tertiary allylic/benzylic C-H compounds to allergenic hydroperoxides/epoxides, and a proposed bio-sulfation route for benzylic alcohols — which could explain part of the unexplained 55% for chemicals with those structural motifs. The same paper separately proposes that some LLNA-positive, alert-free fragrance chemicals (hexyl/benzyl salicylate) may be LLNA false positives rather than true sensitizers at all, which would pull in the opposite direction (shrinking, not explaining, the true no-mechanism fraction) if any such chemicals are present in this claim's 62-ingredient set — not checked here, so the net effect on the 55% figure is unresolved and the grade is left unchanged.
Source: Lee 2024, Food and Chemical Toxicology Industry-funded Link to this fact
The industry / Lab study (cells or chemistry)
Those models underestimated allergy potency by more than fivefold for 18% of the 188 chemicals tested, and more than tenfold for 11%.
Moderate evidence.
Caveats
Prediction error, not a safety-limit error; worst outliers are non-fragrance chemicals. Natsch 2023 (same author, human-anchored retraining) shows this outlier structure is not simply an artifact of fitting to mouse data: only 6/139 chemicals (4.3%) shift by more than 3.3-fold when the same models are retrained against human-anchored potency values instead of LLNA.
Source: Natsch & Gerberick 2022, ALTEX Industry-funded Link to this fact
The industry / Industry source
The industry's standard safety package for a fragrance ingredient in 1994 covered acute poisoning and skin effects (irritation, allergy, sun reactions); breathing it in was not tested, because the industry judged inhalation 'not a route of toxicological concern'.
Moderate evidence.
Caveats
As of 2024, RIFM/Creme Global's aggregate exposure model (Lee 2024) does now include a full inhalation-TTC branch across ~3,000 fragrance ingredients (99% below the inhalation TTC), so the industry itself has since closed this specific 1994 scope gap methodologically — though whether ingredients assessed only under the older dermal-only dossiers were individually revisited is not stated. The gap's closure was gradual, not a single 2024 event: Comiskey et al. 2017 (Phase 2 of the same RIFM/Creme model) added the model's first-ever inhalation branch, 23 years after this 1994 dismissal, but only for air-care and personal-care spray products — household cleaning and laundry products were explicitly still excluded and named as future work in 2017, closing only in the 2024 paper.
Source: Ford 1994 (RIFM) Industry-funded Link to this fact
The industry / Lab study (cells or chemistry)
When the same lab-dish tests that replace animal testing are checked against real human allergy-test panels instead of mouse data, they explain only about 32-45% of how strongly a chemical causes allergy in people, and the mouse test itself does barely better, explaining only 43%.
Moderate evidence: The strictly-human comparison dataset (n=62) is small and the author flags it as biased/non-representative; a larger human dataset might do better.
Source: Natsch 2023, ALTEX Industry-funded Link to this fact
The industry / Lab study (cells or chemistry)
Neither the animal test nor its lab-dish replacements are strong predictors of real human allergy thresholds; they are about equally weak, shown independently in 2015 and again in 2023.
Moderate evidence: Both comparisons reuse overlapping historical human patch-test literature (HRIPT/HMT), not independent new human data.
Source: Natsch 2023, ALTEX Industry-funded Link to this fact
The industry / Lab study (cells or chemistry)
Whether a chemical is irritating to cells in a dish, not just whether it reacts with proteins, drives a lot of the mouse allergy test's readout in ways that don't reflect real human allergy.
Moderate evidence: Statistical inference from regression coefficients across three chemical subsets, not a direct mechanistic experiment.
Source: Natsch 2023, ALTEX Industry-funded Link to this fact
The industry / Lab study (cells or chemistry)
The fragrance industry's own 2007 safety review of benzyl salicylate assessed allergy, toxicity, and cancer risk in detail but never tested it for hormone-like activity at all; the first test came two years later, from an independent lab with no fragrance-industry funding.
Moderate evidence.
Caveats
The independent test found only a weak, partial effect, at concentrations well above the industry's own worst-case exposure estimate, so this closes a testing gap rather than reversing the 2007 review's 'safe as used' conclusion.
Source: Charles & Darbre 2009, Journal of Applied Toxicology Link to this fact
The industry / Measured in people or real products
In RIFM's own comparison of 57 fragrance chemicals, the mouse test used to set fragrance skin-allergy safety limits agreed with real human sensitization thresholds within about 3-fold for 76% of the chemicals tested, but was off by up to nearly 800-fold for others, including hexyl and benzyl salicylate.
Moderate evidence.
Caveats
Single paper/author group (RIFM staff plus an industry consultant), though a large (57-chemical), systematically protocolled primary dataset; the authors themselves call the outlier groups 'an alert for consideration, rather than… a general rule' given only 7 materials populate each. Corroborates, from a different metric and era, the LLNA-human accuracy gap C230 documents for the newer non-animal replacement tests.
Source: Api, Basketter & Lalko 2014, Cutaneous and Ocular Toxicology Industry-funded Link to this fact
The industry / Measured in people or real products
The study's own authors note that current diagnostic patch-test concentrations for oxidized linalool allergy are more than 500 times higher than the hydroperoxide levels they actually found in consumer products.
Moderate evidence: Industry-funded interpretation; does not itself prove patch tests over-diagnose, since already-sensitized skin can react to much lower doses than the diagnostic test threshold.
Source: Kern 2014, Analytical and Bioanalytical Chemistry Industry-funded Link to this fact
The industry / Measured in people or real products
Despite thousands of positive allergy-test reactions to oxidized limonene and linalool reported worldwide, the fragrance industry's own market-testing program concluded that where people are actually getting exposed to these allergens "remains elusive" — the industry itself has not identified the real-world consumer-product source of a widely documented skin allergy.
Moderate evidence.
Caveats
This is the industry's own conclusion, from an industry-funded study; it does not mean the allergy is not real or not caused by fragrance chemicals — only that the specific consumer-product exposure route has not been chemically confirmed even by the party with the strongest incentive to find an innocuous explanation.
Source: Natsch 2019, Food and Chemical Toxicology Industry-funded Link to this fact
The industry / Review of other studies
When RIFM's own scientists switched from mainly human patch-test data (their 2017 categorization) to a full weight-of-evidence approach that also folds in animal, computer-model, and lab-dish data, the assigned allergy-potency category changed for 29% of the same 82 fragrance chemicals — moving to a weaker category for 20.5% of them and a stronger one for 8.5%.
Moderate evidence.
Caveats
Same authors and institution comparing their own two categorization schemes; independent validation of either scheme against real-world human sensitization rates is not addressed in this paper.
Source: Na et al. 2022, Dermatitis Industry-funded Link to this fact
The industry / Other evidence
The fragrance industry lowered its recommended limit for isoeugenol in consumer products from 0.2% to 0.02% in 1998, in response to documented high and rising rates of contact allergy to it.
Moderate evidence.
Caveats
A single documented industry guideline change; the review notes it is unknown whether this will actually reduce isoeugenol sensitization, since chemically similar substitutes can cross-react.
Source: Johansen 2003, Am J Clin Dermatol 4(11):789-798, American Journal of Clinical Dermatology Link to this fact
The industry / Government agency
In February 1992, the Business Council on Indoor Air (an indoor-air industry trade association) told HUD that the American Medical Association, American Association of Allergy and Immunology, American College of Physicians, and American College of Occupational and Environmental Medicine had all stated (December 1991) that there was "inadequate scientific evidence to establish the existence of MCS as a disorder," and asked HUD to correct guidance that recognized MCS as a handicap.
Moderate evidence.
Caveats
Reported via the trade association's own letter and white paper, not read directly from the cited medical-society statements; BCIA is an interested industry group asking a housing regulator to narrow disability protections, which does not by itself make its scientific summary wrong but is a relevant interest to disclose.
Source: BCIA letter (1992) Link to this fact
The industry / Lab study (cells or chemistry)
A 2022 skin-absorption study of linalool, funded by the fragrance industry's own safety institute (RIFM) and run by RIFM's long-term contract lab, tested only fresh linalool and did not report the test material's oxidation state or test air-oxidized linalool, the form clinical studies link to skin allergy.
Moderate evidence: Industry-funded (RIFM); the gap mirrors the same undisclosed-oxidation-state pattern documented in RIFM's separate 2003 sensitization dossier for linalool.
Source: Brain et al. 2022 (An-eX/RIFM), International Journal of Pharmaceutics Industry-funded Link to this fact
The industry / Journalism
The Skin Deep database draws on about 60 sources including IFRA and the industry's own Cosmetic Ingredient Review panel, the EU banned-fragrance list, and the SCCNFP fragrance-allergy opinions, with reference dates running to about 2009; the page does not state whether sources are refreshed.
Moderate evidence: Source list from the page's own references; the live database may use newer data.
Source: EWG Skin Deep methodology page (2026 capture) Link to this fact
The industry / Other evidence
The main safety data set the oxybenzone sunscreen maker offered against clinic reports of oxybenzone allergy is 64 of its own unpublished studies, written up by its employees and former employees; the authors argue clinic-based literature overstates risk because clinic patients already have skin disease.
Moderate evidence.
Caveats
The authors' point about clinic selection is fair, but their healthy-volunteer design cannot measure risk in the photosensitive people where oxybenzone photoallergy is reported. 'Meta-analysis' here means pooling the sponsor's studies, with no search or inclusion criteria.
Source: Agin 2008 (oxybenzone HRIPT), Photodermatology, Photoimmunology & Photomedicine Industry-funded Link to this fact
Information, not medical advice. See also: myths we won’t tell you.