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.
Health effects / Self-reported survey
Among autistic adults reporting health effects from fragranced products, 74.1% considered them potentially disabling under their own country's disability law (85.4% US, 82.4% AU, 54.5% UK), versus 25.4% of non-autistic adults (POR 7.62, 95% CI 4.95-11.72).
Moderate evidence.
Caveats
Self-reported severity against each country's own disability-law wording, not a clinical disability determination; sharp UK/US-AU divergence despite near-identical overall prevalence across countries.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
Health effects / Self-reported survey
59.4% of autistic adults reported losing workdays or a job in the past year because of fragranced-product exposure in the workplace, versus 7.6% of non-autistic adults.
Moderate evidence: Self-report; the comparable item in sibling Steinemann surveys may count 'became sick' without lost time, so this is plausibly an upper bound.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
Health effects / Self-reported survey
Among autistic adults, 62.9% reported health problems from air fresheners or deodorizers, 57.5% from the scent of laundry products from a dryer vent, 65.9% from being in a room cleaned with scented products, 60.5% from being near someone wearing a fragranced product, and 64.3% from other fragranced products (pooled across the US, Australia, and UK).
Moderate evidence.
Caveats
Pooled 3-country figures only; the paper's main text gives no country-by-country breakdown for these specific exposure items, so secondary citations quoting a country split (e.g. 71.4%/51.2% for the dryer-vent item) cannot be verified against this primary's own tables.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
Health effects / Self-reported survey
35.9% of autistic adults reported asthma attacks and 42.9% reported migraine headaches associated with fragranced products, versus 6.2% and 10.0% of non-autistic adults respectively.
Moderate evidence: Self-report, no clinical confirmation of asthma, migraine diagnosis or attribution to fragrance.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
Health effects / Measured in people or real products
Among hotel workers directly handling cleaning products, bleach, and laundry chemicals, the average estimated excess lifetime cancer risk from inhaled VOCs (4.1 in 100,000) was about 40 times the EPA's 1-in-a-million screening threshold, driven more than two-thirds by formaldehyde (then chloroform and benzene), even though measured VOC concentrations were at the low end of those reported in US buildings generally.
Moderate evidence: Preliminary/screening-level risk estimate extrapolated from short-term (6-9h) measurements to a 40-hr workweek; small sample (2 hotels); not a measured cancer incidence.
Health effects / Measured in people or real products
Despite directly and repeatedly handling cleaning products and bleach all shift, hotel housekeepers', laundry, maintenance, and office workers' calculated non-cancer hazard ratios for VOC exposure all fell below the standard threshold of 1 (ranging 0.3-0.5 across worker groups), though all remained above the more conservative 0.1 margin-of-safety benchmark the authors mention; formaldehyde contributed most of the hazard for every group except the single maintenance worker, where a lubricant-derived alkane (n-nonane) contributed slightly more (54% vs 46%).
Moderate evidence: Preliminary screening-level estimate from short-term sampling; maintenance-worker group size n=1.
Health effects / Self-reported survey
In a study of 74 French migraine patients and 30 controls, 35.2% of migraineurs (26/74) but no controls reported interictal olfactory hypersensitivity (OHS) — unusual sensitivity to ordinary smells between attacks, distinct from osmophobia during an attack.
Moderate evidence: Single-center, cross-sectional, self-report OHS ascertainment with no objective olfactory threshold testing.
Health effects / Self-reported survey
Migraine patients with interictal olfactory hypersensitivity scored far higher on a validated 5-item chemical odor intolerance index (pesticide, paint, perfume, new carpet, car exhaust) — 18.7 +/- 3.2 — than migraineurs without it (11.7 +/- 3.6) or headache-free controls (9.9 +/- 3.5), a clear dose-like gradient (all pairwise P <= 0.02).
Moderate evidence: Single-center, cross-sectional; the index is validated but coarse (5 items) and self-report.
Health effects / Self-reported survey
Among migraineurs, logistic regression linked interictal olfactory hypersensitivity to odor-triggered migraine (OR=5.347, 95% CI 1.426-20.043, P=0.0091), higher attack frequency, and visual hypersensitivity, but not to disease duration, age, sex, aura status, or auditory hypersensitivity.
Moderate evidence.
Caveats
Cross-sectional association, not causal; the reported odds ratios for attack frequency and visual hypersensitivity are below 1 despite OHS patients having the higher mean on both, an unexplained coding-direction detail in the original paper.
Health effects / Self-reported survey
Migraineurs with interictal olfactory hypersensitivity rated 12 everyday odorants (including mushroom, pine, strawberry, lemon, lavender, ether, mint, vinegar) as less pleasant than other migraineurs and controls — especially ether — while their intensity ratings of the same odorants did not differ from either group, pointing to an altered hedonic rather than psychophysical response.
Moderate evidence: Small single-center sample; hedonic rating is a behavioral task, not a biomarker, and the group-odor interaction was only a trend (P=0.0514).
Health effects / Self-reported survey
In a cross-sectional study of 113 German migraine patients, hypersensitivity to odors was reported by 38.1% preictally (before an attack), 61.9% ictally (during an attack), and 31.9% interictally (between attacks); 30.1% reported that odors could trigger a migraine attack.
Moderate evidence: Single tertiary-center, cross-sectional, self-reported via four non-validated yes/no questions; no healthy-control comparison or objective olfactory testing.
Source: Gossrau 2022, The Journal of Headache and Pain Link to this fact
Health effects / Self-reported survey
Migraine patients who reported interictal (between-attack) odor hypersensitivity had a significantly longer median disease duration than those who did not (28.5 vs. 20.0 years, p=0.015) and were on average 10 years older (p=0.002); no such disease-duration or age association was found for preictal or ictal hypersensitivity.
Moderate evidence.
Caveats
Cross-sectional association, not causal; cannot distinguish whether longer disease duration drives interictal sensitization or interictal sensitization (or age itself) drives a longer recorded disease course.
Source: Gossrau 2022, The Journal of Headache and Pain Link to this fact
Health effects / Self-reported survey
Interictal odor hypersensitivity in this cohort was positively associated with odor-triggered migraine attacks (OR=4.419, 95% CI 1.783-10.952, p=0.001) and with ictal hypersensitivity (OR=3.546, 95% CI 1.218-10.324, p=0.020) — the opposite direction from a Brazilian study (Fornazieri 2016) that found interictal hypersensitivity associated with LOWER osmophobia and trigger rates, but the same direction as an earlier French study (Demarquay 2006).
Moderate evidence.
Caveats
Three studies, three different self-report instruments, three different populations (German, Brazilian, French); instrument and population differences are not controlled for and could explain the direction split without implying a true biological paradox.
Source: Gossrau 2022, The Journal of Headache and Pain Link to this fact
Health effects / Self-reported survey
Preictal (premonitory-phase) odor hypersensitivity was strongly associated with both ictal hypersensitivity (OR=10.611, 95% CI 3.355-33.557, p<0.001) and with self-reported odor-triggered migraine attacks (OR=2.896, 95% CI 1.139-7.364, p=0.026), replicating in a second German cohort the pattern used elsewhere to argue that 'odor triggers my migraine' may often be a misattributed premonitory symptom rather than an independent external cause.
Moderate evidence: Cross-sectional, retrospective self-report design; cannot prospectively distinguish a genuine external trigger from a misattributed symptom of an attack already underway.
Source: Gossrau 2022, The Journal of Headache and Pain Link to this fact
Health effects / Self-reported survey
Patients with higher migraine-related disability (MIDAS) more often reported preictal odor hypersensitivity (OR=2.653, p=0.037) and had significantly higher MIDAS scores if they reported interictal hypersensitivity (median 37.0 vs. 23.0, p=0.004) or odor-triggered attacks (median 36.0 vs. 23.0, p=0.022); ictal hypersensitivity was not significantly associated with MIDAS category.
Moderate evidence: Cross-sectional association; does not establish that osmophobia causes greater disability or vice versa.
Source: Gossrau 2022, The Journal of Headache and Pain Link to this fact
Health effects / Other evidence
Intact methylparaben, ethylparaben, n-propylparaben, n-butylparaben, and isobutylparaben were detected in human breast tumor tissue, with methylparaben the dominant paraben at 62% of a mean total of 20.6 ng/g tissue.
Moderate evidence.
Caveats
Single lab, n=20 tumor-only convenience sample with no normal-tissue control; analytical recovery was only ~48.5%; procedural blank values were large and variable relative to the signal, and 2 of 20 tumors had negative blank-corrected totals.
Source: [[src-2004-concentrations-parabens-breast-tumours|Darbre 2004]], Journal of Applied Toxicology Link to this fact
Health effects / Measured in people or real products
In an industry-run human mass-balance study, only about 0.5% of the para-phenylenediamine (PPD) applied in a real commercial dark-shade oxidative hair dye was absorbed into the body (urine plus feces), amounting to about 7 milligrams out of roughly 1.3 grams applied, with the rest rinsed off in the first wash or remaining on the clipped hair.
Moderate evidence.
Caveats
Single 8-subject study, all male, industry-run (4 of 5 authors L'Oreal employees); a single consumer-type application, not repeated or occupational use; individual subjects ranged 0.32-1.02% absorbed, a 3-fold spread.
Source: Hueber-Becker et al. 2004, Food and Chemical Toxicology Industry-funded Link to this fact
Health effects / Measured in people or real products
In an industry-sponsored radiolabeled-tracer study, professional hairdressers' estimated systemic daily dose of para-phenylenediamine (PPD) from oxidative hair dyeing, even on a day with 6 full dye applications, was under 0.36 micrograms per kilogram body weight.
Moderate evidence.
Caveats
Single 18-subject study, sponsored by L'Oreal and other hair dye producers, three of seven authors L'Oreal employees; conducted with researcher-supervised training heads rather than real salon clients; the figure is the authors' own conservative upper bound (every non-detect urine sample counted as present at the limit of quantification).
Source: Hueber-Becker et al. 2007, Food and Chemical Toxicology Industry-funded Link to this fact
Health effects / Measured in people or real products
Hand contamination with PPD-equivalents was about 25-fold higher after cutting and drying just-dyed hair without gloves (148 ng/cm2) than after mixing and applying the dye while wearing gloves (6 ng/cm2), in the same study.
Moderate evidence: This is a between-task comparison (a gloved task vs. a different, ungloved task), not a controlled gloves-vs-no-gloves test of the same task.
Source: Hueber-Becker et al. 2007, Food and Chemical Toxicology Industry-funded Link to this fact
Health effects / Measured in people or real products
Baby powder use was associated with 60% higher levels of the phthalate metabolite MiBP, and baby shampoo use with 40% higher levels of the metabolite MMP, in a study of 163 US infants.
Moderate evidence: Associations only, not shown to be causal; product content was not measured.
Source: Sathyanarayana et al. 2008, Pediatrics Link to this fact
Health effects / Review of other studies
Reviewing 18 lab studies that met her own 5 empirical criteria, Herz found credible evidence that inhaled odors can affect mood, cognition, physiology and behavior, but results for the same odor (e.g., lavender, rosemary) were frequently inconsistent across laboratories and across dependent measures (subjective, physiological, behavioral).
Moderate evidence: Narrative (not systematic) review by a single author; only 18 of several hundred PubMed-identified articles met inclusion criteria; no PRISMA or formal quality appraisal.
Source: Herz 2009, International Journal of Neuroscience Industry-funded Link to this fact
Health effects / Review of other studies
No human study has shown that inhaled, aromatherapy-dose essential oil volatiles reach the bloodstream, and most reported mood/physiology effects of odors occur immediately rather than after the roughly 20 minutes a blood-borne (pharmacological) mechanism would require.
Moderate evidence.
Caveats
Absence-of-evidence argument; the review does not report a study that directly measured blood levels of inhaled aromatherapy-dose volatiles in humans, only rodent data (Jirovitz 1990, 1992; Kovar 1987).
Source: Herz 2009, International Journal of Neuroscience Industry-funded Link to this fact
Health effects / Measured in people or real products
In a controlled study of 90 female college students, simply telling them an ambient odor (lavender, neroli, or no odor at all) was "relaxing" lowered their heart rate and skin conductance, and telling them it was "stimulating" raised them, regardless of which odor — if any — was actually present.
Moderate evidence: Female-only sample (n=90); not independently replicated in the studies Herz reviewed.
Source: Campenni et al. 2004, via Herz 2009, International Journal of Neuroscience Industry-funded Link to this fact
Health effects / Measured in people or real products
Brominated flame-retardant chemicals (PBDEs) in Korean mothers' breast milk were among the highest levels measured anywhere in the world, comparable to or higher than North America, though the study's own calculated hazard quotients for infant intake of the three most abundant PBDEs were all below 1 (0.62, 0.42, and 0.19).
Moderate evidence.
Caveats
N=20 Korean mothers, 2007 samples; a hazard quotient below 1 reflects the study's own non-cancer reference-dose comparison for three congeners only (BDE-47, -99, -153), not a finding of safety for synthetic musks or for PBDE mixtures generally; the authors call for larger, longer-term studies.
Health effects / Measured in people or real products
In a second FDA trial of 48 healthy adults, all 6 tested sunscreen active ingredients — avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate — exceeded the FDA's 0.5 ng/mL systemic-absorption threshold after just a single application on day 1, not only after days of repeated maximal use.
Moderate evidence.
Caveats
Single trial from one research team/site; exceeding the threshold is a regulatory trigger for more toxicology testing, not a finding that the ingredients are unsafe — the paper explicitly states these findings do not indicate people should stop using sunscreen.
Source: Matta 2020, JAMA Link to this fact
Health effects / Measured in people or real products
Oxybenzone reached a geometric mean peak blood concentration of up to 258.1 ng/mL (lotion) in this FDA trial, roughly 500 times the agency's own 0.5 ng/mL toxicology-waiver threshold, and stayed above that threshold in more than three-quarters of participants through day 21, the last day the trial measured.
Moderate evidence.
Caveats
Maximal-use protocol (2 mg/cm2 over 75% of body surface area, repeated dosing days 2-4); the study stopped measuring at day 21, so it is unknown when oxybenzone levels actually fell below threshold.
Source: Matta 2020, JAMA Link to this fact
Health effects / Measured in people or real products
Three sunscreen active ingredients never previously measured in human plasma — homosalate, octisalate, and octinoxate — were shown in this FDA trial to be systemically absorbed above the 0.5 ng/mL threshold, with homosalate reaching a geometric mean peak of up to 23.1 ng/mL (about 46 times the threshold) and remaining above threshold in over half of participants through day 21.
Moderate evidence.
Caveats
Single trial; formulations tested used sub-maximal concentrations of at least one ingredient relative to the US legal maximum, so market products at full concentration could absorb more.
Source: Matta 2020, JAMA Link to this fact
Health effects / Measured in people or real products
In a small longitudinal pilot study of 25 women tracked across one menstrual cycle, tampon users had significantly higher urinary concentrations of 2-butanone (β=1.58 log ng/g, 95% CI 0.16-3.00, p=0.03) and methyl isobutyl ketone (β=0.63 log ng/g, 95% CI 0.03-1.22, p=0.04) than pad/liner users, after adjusting for race, visit, and background VOC exposure.
Moderate evidence.
Caveats
Small pilot cohort (n=25); observational, no causal claim; most other VOCs tested (hexane, n-nonane, hexanal, nonanal, benzene, toluene, p-isopropyltoluene) showed no significant tampon-vs-pad difference.
Source: Ding 2022, Journal of Women's Health Link to this fact
Health effects / Measured in people or real products
Women whose menstrual products contained more n-nonane, benzene, or toluene (based on the group's prior product-testing data) had correspondingly higher urinary levels of those same chemicals: n-nonane β=6.60 log ng/g (95% CI 1.63-11.57, p=0.009), benzene β=0.85 (95% CI 0.13-1.58, p=0.02), toluene β=0.13 (95% CI 0.03-0.22, p=0.009).
Moderate evidence: First direct product-content-to-urinary-biomarker linkage in this research line; small pilot cohort (n=25); observational.
Source: Ding 2022, Journal of Women's Health Link to this fact
Health effects / Measured in people or real products
Urinary VOC concentrations did not vary significantly across the menstrual cycle in this pilot (no significant change at any of 4 visits for any of 9 commonly detected VOCs); the hypothesized rise during heavy bleeding and decline afterward was not observed.
Moderate evidence: Null result; small pilot cohort (n=25) may be underpowered to detect a cycle-phase effect.
Source: Ding 2022, Journal of Women's Health Link to this fact
Health effects / Other evidence
A toxicokinetic model estimates that fat-soluble fragrance/solvent chemicals from feminine hygiene products (p-cymene, hexane, n-nonane) can build up in body fat to levels 1 to 4 orders of magnitude higher than in blood or urine, even though skin levels stay low.
Moderate evidence: Modeled, not directly measured in body fat; single research group's model not yet independently replicated.
Source: Lin 2025, Environmental Health Perspectives Link to this fact
Health effects / Other evidence
In a worst-case modeled exposure scenario, n-nonane from feminine washes approached a conservative no-appreciable-risk threshold (hazard ratio 0.07 of 0.1) and benzene from moisturizers exceeded a conservative cancer-risk threshold of 1 in 10 million, reaching about 1.8 in 10 million.
Moderate evidence: Highest-exposure scenario, not typical use; best-guess scenario risks were well below any threshold.
Source: Lin 2025, Environmental Health Perspectives Link to this fact
Hidden ingredients / Measured in people or real products
In a test of 6 best-selling US air fresheners and laundry products, researchers found 98 chemical detections (58 different chemicals) released into the air; none appeared on any product label, and only 1 (ethanol) appeared on a safety data sheet.
Moderate evidence: N=6 products, headspace only, semi-quantitative.
Source: Steinemann 2009, Environmental Impact Assessment Review Link to this fact
Hidden ingredients / Measured in people or real products
4 of the 6 products released at least one chemical the Clean Air Act classifies as a hazardous air pollutant (acetaldehyde, chloromethane, or 1,4-dioxane), and none was listed.
Moderate evidence: Paper text says 5 of 6; tables support 4. Two of three HAPs come from the base formulation, not fragrance.
Source: Steinemann 2009, Environmental Impact Assessment Review Link to this fact
Hidden ingredients / Self-reported survey
68.6% of Australians were unaware that fragrance ingredients don't have to be fully listed on labels.
Moderate evidence: Awareness survey item.
Source: Steinemann 2017, Preventive Medicine Reports Link to this fact
Hidden ingredients / Self-reported survey
73.4% of Swedes didn't know fragrance ingredients don't have to be fully disclosed, and 70.9% didn't know that fragranced products sold as 'green' or 'organic' can also release potentially hazardous air pollutants.
Moderate evidence: Awareness items; the HAP premise itself rests on other studies.
Source: Steinemann 2018 (Sweden), Air Quality, Atmosphere & Health Link to this fact
Hidden ingredients / Measured in people or real products
When researchers tested 25 best-selling US laundry, cleaning, personal-care, and air-freshener products, they found 133 different chemicals released into the air, but only 1 of them was listed on any product label.
Moderate evidence: Single headspace sample per product; VOC counts depend on detection threshold.
Source: Steinemann 2011, Environmental Impact Assessment Review Link to this fact
Hidden ingredients / Measured in people or real products
11 of 25 best-selling fragranced products (44%) released at least one chemical the EPA classes as a probable cancer-causing air pollutant, such as acetaldehyde or 1,4-dioxane, though the study couldn't tell whether these came from the fragrance or the rest of the formula.
Moderate evidence: Headspace, not exposure; mostly base-formula compounds.
Source: Steinemann 2011, Environmental Impact Assessment Review Link to this fact
Hidden ingredients / Self-reported survey
About two-thirds (64.6%) of US adults did not know fragrance ingredients don't have to be listed on the label, and more than half would prefer fragrance-free workplaces (53.2% vs 19.7% against) and health care (54.8% vs 22.4%).
Moderate evidence: Opinion survey.
Source: Steinemann 2016, Air Quality, Atmosphere & Health Link to this fact
Hidden ingredients / Measured in people or real products
Counting the word "parfum" undercounts scented children's products, because essential oils and individual fragrance chemicals are listed under other names.
Moderate evidence: Undercount size not measured for these products.
Source: Uber 2024, Jornal de Pediatria (Rio de Janeiro) Link to this fact
Hidden ingredients / Measured in people or real products
In a test of 42 fragranced baby products (shampoos, lotions, oils, sprays), 95% of the chemicals they released into the air were not listed on the label, safety data sheet, or company website.
Moderate evidence: Headspace presence only; Australian products.
Source: Nematollahi 2018, Air Quality, Atmosphere & Health Link to this fact
Hidden ingredients / Measured in people or real products
The best-selling US laundry detergent's label and safety sheet disclosed almost none of what it released; only ethanol was listed.
Moderate evidence: Same detergent measured in 2009, 2011, and 2013 papers; count once.
Source: Steinemann 2013, Air Quality, Atmosphere & Health Link to this fact
Hidden ingredients / Review of other studies
One product's safety data sheet listed twelve ingredients, every one of them only as 'trade secret' at '1-100%'.
Moderate evidence: Single example cited by EPA authors.
Source: Goldsmith 2014, Food and Chemical Toxicology Link to this fact
Hidden ingredients / Review of other studies
In a German test of six air fresheners, more than 90% of the chemicals they released were not declared on the product.
Moderate evidence: Secondary citation of Uhde & Schulz 2015 (not in our evidence base); by number of substances (>75% by concentration).
Source: Steinemann 2017, Building and Environment Link to this fact
Hidden ingredients / Review of other studies
Fragrance turns up in products people don't think of as scented: household cleaners and detergents, tampons and panty liners, medicines, medical devices, toys, and candles.
Moderate evidence: Qualitative list of exposure sources.
Source: Sukakul 2024, Acta Dermato-Venereologica Industry-funded Link to this fact
Hidden ingredients / Self-reported survey
When companies replace a chemical of concern, they often swap in one with far less safety data; one firm found a supplier's 'safer' substitute only looked safer because more of its ingredients were kept confidential.
Moderate evidence: Interview quotes and one anecdote.
Source: Scruggs 2011, Environmental Science & Policy Link to this fact
Hidden ingredients / Review of other studies
Testing cited by a 2010 review claimed the fragrance solvent DEP was found in all fragrances tested and in 71% of cosmetics, but the largest independent survey since (Koniecki 2011, n=252) found DEP in 70% of fragrances and 41% of cosmetics overall — lower than either earlier figure.
Moderate evidence.
Caveats
Secondary citation of EWG's 2002 testing (n=72), relayed via Crinnion 2010. Two larger, later, independent surveys (Hubinger & Havery 2006, n=48; Koniecki 2011, n=252) confirm DEP is common and fragrance-concentrated but do not reproduce the specific 100%/71% figures; detection frequency falls as sample size rises across all three surveys. Treat 'all'/'71%' as an upper bound from small early samples, not a population estimate.
Source: Crinnion 2010, Alternative Medicine Review Link to this fact
Hidden ingredients / Review of other studies
FDA's voluntary cosmetic registration listed benzyl alcohol in only 322 formulations in 1998 and 511 products in 2006, far below its real use in moisturizers, shampoos, baby products, and deodorants, which the authors call widespread under-reporting.
Moderate evidence.
Caveats
The 322-formulation count for 1998 is now confirmed against the primary source: CIR's 2001 safety report (Nair 2001) reproduces the identical FDA VCRP count in its own Table 2, with a full 34-category breakdown (largest use hair dyes and colors, 130/1572; baby shampoos 5/21; baby lotions 3/53) — this is the exact table Jacob & Barron's figure traces to, not a secondhand citation. The 511-products-in-2006 figure remains an unpublished personal communication (postdates the 2001 report, so it cannot confirm or deny it). The same 2001 report separately documents that FDA stopped collecting concentration-of-use data after 1992, an independently CIR-acknowledged registry gap that supports treating VCRP counts as an incomplete picture of real use, distinct from the authors' own 'under-reporting' framing.
Hidden ingredients / Review of other studies
The glycol-ether solvent propylene glycol methyl ether (PGME), mostly used in industrial coatings and cleaners, is officially listed as a possible 'fragrance ingredient' in cosmetics, and a Swiss survey found it making up 30–50% of one perfume.
Moderate evidence: INCI function listing plus one Swiss product survey (Dentan 2000, cited secondhand); US registry shows only nail-product uses.
Source: CIR 2008, International Journal of Toxicology Industry-funded Link to this fact
Hidden ingredients / Review of other studies
The single word 'fragrance' on a label can stand for dozens to hundreds of chemicals. The fragrance industry's own inventory (RIFM) lists about 2,600 chemicals in current active use, plus roughly 3,500 discontinued materials it keeps only for internal read-across comparison.
Moderate evidence.
Caveats
Primary now read directly (Date 2020, RIFM): ~2,600 active-use + ~3,500 discontinued = the 'over 6,000' figure in its abstract. Rádis-Baptista 2023 paraphrased this as '6,000 known, 2,000 used,' which is not what Date 2020 reports. This is the industry's own inventory count, corroborated only within RIFM's own publications, not independently, so it stays at moderate rather than strong.
Source: Rádis-Baptista 2023, Journal of Xenobiotics Link to this fact
Hidden ingredients / Review of other studies
Several hundred different label names can signal fragrance (chemical names, over 50 essential oils by common or Latin name, and synonyms such as aroma, parfum, perfume, and scent), so dermatologists say allergic patients are very unlikely to find fragrance-free products by reading labels alone.
Moderate evidence: Expert opinion.
Hidden ingredients / Review of other studies
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.
Caveats
Industry-funded letter (Consortium Huiles Essentielles, Giroux & Orjubin 2020), results as prose with no concentrations, detection limits, lab or sample provenance; not independently confirmed. The label did not claim lavender, so this is not a mislabeling example.
Source: Braunstein & Braunstein 2023, touchREVIEWS in Endocrinology Industry-funded Link to this fact
Hidden ingredients / Review of other studies
Nobody independently analyzed the products used by the children in the 2019 lavender breast-growth case reports: the only published analysis was by an essential-oil trade consortium, which covered two of the three products and reported no numbers; the researchers concede the products contain other, partly synthetic, substances whose composition may vary by where they were bought.
Moderate evidence.
Caveats
One earlier product was analyzed independently of industry: Diaz 2016 (now read as a primary), from the same clinic, used academic HPLC-UV/MS (McMaster University) to confirm linalool and linalyl acetate in an agua de violetas cologne. That analysis concerns Diaz's own Case 2 patient, not any of the three products used by Ramsey 2019's four patients (Mi Tesoro, Crusellas Violet Water, Baby Magic baby bath), so the claim as it applies to Ramsey 2019's own case-report products stands: none of those three was ever independently analyzed. The NIEHS reply to the consortium letter on the third product (dgaa227) has still not been read.
Source: Ramsey et al. 2020 (JCEM reply), The Journal of Clinical Endocrinology & Metabolism Link to this fact
Hidden ingredients / Self-reported survey
About a third of the personal care products people actually used were not in EWG's Skin Deep database at all, including 39% of perfumes and nearly all intimate-care products, so their hazards could not be rated.
Moderate evidence: Database coverage as of July 2022; EWG has since added products.
Source: Barrett 2025, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Hidden ingredients / Measured in people or real products
Once in the air, scent chemicals such as linalool, ionones, and the woody musk OTNE ('Iso E Super') reacted with ozone to form dozens of new oxidized chemicals, including a hydroperoxide. None of these was in the product.
Moderate evidence: Compound identities are tentative (formula-level mass spectrometry); products unquantified; no hazard testing.
Source: Wu 2024, Environmental Science & Technology Letters Link to this fact
Hidden ingredients / Animal study
The regulatory endocrine dossier on linalool tested 99.7%-pure, freshly handled material — not the air-oxidized linalool that forms in an opened bottle and that accounts for almost all of linalool's known allergy risk. Nobody has tested whether oxidized linalool is hormonally active.
Moderate evidence: This is standard and correct practice for a REACH dossier; it is a limit on what the result covers, not a flaw in the study.
Source: Hareng 2024, Archives of Toxicology Industry-funded Link to this fact
Hidden ingredients / Review of other studies
Plastic particles are added to cosmetics on purpose for texture, a silky or powdery feel, opacity, shimmer, and as carriers for other ingredients, not only as scrub beads; and the EU chemicals agency's definition does not count liquid, semi-solid, or water-soluble polymers as microplastics.
Moderate evidence: Definition statement is the review's reading of ECHA; check against Regulation (EU) 2023/2055.
Hidden ingredients / Review of other studies
PFOA and GenX, both EU Substances of Very High Concern, may be used in making PTFE; a 2024 review says these impurities must be kept to a minimum but reports no measured levels in cosmetics, and the label says only 'PTFE'.
Moderate evidence.
Caveats
No measurement of PFOA/GenX in any PTFE-containing cosmetic in this paper or our evidence base; presence in PTFE specifically is plausible, not shown. Namazkar 2024 (10.1039/d3em00461a) has since measured residual PFCAs including a C4-C8 (PFOA-range) chain-length span at 0.02-1.29 ug/g, 43-76% dermally bioaccessible, in real cosmetics — but in products listing PAPs/silanes/ethers, not PTFE. Balan et al. 2024 (10.1021/acs.est.3c06539) explicitly classifies PTFE as NOT a PFAA precursor (per Harris 2022). Oshima et al. 2020 (10.1038/s41598-020-70918-x, now a evidence base primary) directly measures PFOA formation (25.6-28.3 ppb) from the irradiation process used to make low-Mw PTFE micropowder, confirming the manufacturing mechanism is real — but tests industrial, not cosmetic-grade, PTFE, so it still does not measure PFOA/GenX in any cosmetic. Net effect: the mechanism this claim describes is now directly measured (not just asserted); the cosmetic-product measurement it lacks is still missing, so strength stays moderate.
Source: Jomaa 2024, Journal of the Netherlands Society of Toxicology (JNST) Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
In 2018, testing commissioned by Breast Cancer Prevention Partners of 25 personal care and 7 cleaning products found chemicals flagged for cancer, hormone disruption, respiratory, or developmental hazards that were not on the label; 99 of the 124 were on the fragrance industry's own ingredient list.
Moderate evidence: Not peer reviewed; labs, detection limits, and concentrations not reported; hazard = database flag; IFRA list includes multifunctional solvents/preservatives.
Source: BCPP 2018 Link to this fact
Hidden ingredients / Advocacy group testing
In a 2010 survey of more than 11,000 Canadian personal-care products with ingredient lists, 'fragrance' or 'parfum' was the most common ingredient of concern, listed on 56% of products and on about two-thirds of shampoos, soaps, and deodorants.
Moderate evidence: Self-selected volunteers read labels; product entries not de-duplicated; 2010 formulations; label count is a lower bound on fragranced products.
Information, not medical advice. See also: myths we won’t tell you.