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.
Hidden ingredients / Measured in people or real products
In lab tests of 213 US household and personal-care products, not one label listed a phthalate, yet the phthalate DEP, a common fragrance solvent, turned up in half of the pooled conventional product samples.
Strong evidence: Products bought 2007-08; composited samples; content not dose.
Source: Dodson 2012, Environmental Health Perspectives Link to this fact
Hidden ingredients / Review of other studies
US law does not require the individual chemicals in a fragrance to be listed, so a shopper cannot tell from the label whether a scented product contains diethyl phthalate.
Strong evidence: Regulatory background statement, as of 2013.
Source: Parlett 2013, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Hidden ingredients / Review of other studies
None of the products used by the four affected children was ever chemically analyzed; the researchers could only assume that a product labeled as containing lavender oil actually met the international composition standard.
Strong evidence.
Caveats
Stated by the authors as a limitation; an industry letter later claimed one named cologne contained diethyl phthalate and no lavender oil, which has also never been independently verified.
Source: Ramsey 2019, The Journal of Clinical Endocrinology & Metabolism Link to this fact
Hidden ingredients / Review of other studies
The industry's own safety panel wrote that a single fragrance can contain 50-300 ingredients, that formulas are 'carefully guarded', and that the industry 'is often perceived as rather less than forthcoming by consumers and their physicians'.
Strong evidence: Direct quotation from an industry-authored 2003 paper; 50-300 is a range, not a measured count.
Source: Bickers 2003 (RIFM Expert Panel), Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
Hidden ingredients / Advocacy group testing
Ingredient labels cannot show what is inside 'parfum': a 2010 Canadian cosmetics survey had to leave out diethyl phthalate, a common fragrance solvent, because 'short of a laboratory analysis, there's no way to know'.
Strong evidence: Illustrative quote; for measured prevalence cite Dodson 2012 (DEP in 21/42 conventional composites, no label listed a phthalate).
Hidden ingredients / Government agency
US cosmetic labels can still say just "fragrance". The 2022 law requires companies to name fragrance allergens on the label, but only the ones the FDA lists in a regulation, which the law told the FDA to propose by June 2024.
Strong evidence: Statute §609(b); allergens, number and thresholds left to FDA; check whether the final rule is in force before saying labels carry them.
Source: MoCRA 2022 Link to this fact
Hidden ingredients / Government agency
Even the FDA can only ask what is in a cosmetic's fragrance after a serious adverse event it has reason to blame on the fragrance; the company may answer with "categories of ingredients", and the answer is exempt from public-records requests.
Strong evidence: Statute §605(f); 30-day deadline; records access separately excludes formulas (§610).
Source: MoCRA 2022 Link to this fact
Hidden ingredients / Review of other studies
About 1 in 10 (370 of 3,820) topical medicines in a Belgian survey were labeled as containing a fragrance ingredient, and there is no EU or Belgian legislation restricting fragrance in topical medicines.
Strong evidence.
Caveats
Now sourced directly from the primary (Nardelli 2009), not second-hand via Pastor-Nieto 2021; exact figures confirmed (370/3,820 = 9.7%, rounds to the paper's stated 10%). This is a label survey (fragrance listed as an ingredient), not a reaction-rate or chemical-analysis figure; 127 of the clinic's 3,378 iatrogenic-ACD patients (3.8%) had a confirmed reaction to one of the fragranced products. Nardelli 2009's own abstract misprints the product-count denominator as 3,280 — use 3,820 from its Methods/body.
Source: Pastor-Nieto 2021 (Nardelli 2009), Current Treatment Options in Allergy Link to this fact
Hidden ingredients / Review of other studies
Sanitary pads, panty liners and tampons can contain undisclosed fragrance allergens — chiefly alpha-isomethyl ionone (in every scented tampon tested), hexyl cinnamal and benzyl salicylate, plus trace limonene, linalool and geraniol — and in the EU they do not have to declare any of them.
Strong evidence.
Caveats
Primary source (Desmedt 2020, validated HS-GC-MS/FID, 10 scented Belgian AHPs) now in our evidence base. The compounds actually found above the EU 10 ug/g labeling threshold were alpha-isomethyl ionone (all 4 tampons, 12.6-19.1 ug/g), hexyl cinnamal and benzyl salicylate (one panty liner); limonene, linalool and geraniol were all trace (<10 ug/g) — the original claim named the wrong allergens as the notable ones.
Source: Pastor-Nieto 2021 (Desmedt 2020), Current Treatment Options in Allergy Link to this fact
Hidden ingredients / Measured in people or real products
Unlisted PFAS impurities (perfluorocarboxylic acids, including chain lengths that overlap PFOA) were found in nearly every PFAS-containing cosmetic tested in a 2024 study, and these unlisted impurities transferred into artificial sweat far more readily (43-76%) than the PFAS ingredient actually printed on the label (which showed negligible transfer).
Strong evidence.
Caveats
Bioaccessibility (partitioning into artificial sweat) is a precursor to, not proof of, skin absorption; sebum was not included in the assay and may raise this further; small sample; no PTFE-containing products were tested.
Source: Namazkar 2024, Environmental Science: Processes & Impacts Link to this fact
Hidden ingredients / Measured in people or real products
In Belgium, about 1 in 10 topical (skin-applied) pharmaceutical products — wound-healing ointments, NSAID gels, antiseptics, antihemorrhoidals, even corticosteroid-antibiotic creams — listed a fragrance ingredient, sometimes disclosed only as the single word "Perfume".
Strong evidence: 370/3,820 products in a Belgian label survey (2009); a label/composition survey, not chemical analysis; historical product list, not a current market snapshot.
Hidden ingredients / Measured in people or real products
A single undisclosed "Perfume" in one antibiotic-corticosteroid cream (Mycolog/Triadcortyl) caused allergic reactions in 34 patients — more than any other product in a 30-year clinic series — and its 28-ingredient composition was only obtained by directly asking the manufacturer, not from the label.
Strong evidence: Single-clinic case series; one product's undisclosed formula, not a general claim about all perfume-labeled products.
Hidden ingredients / Measured in people or real products
Health Canada's own testing of 252 Canadian cosmetic and personal care products found the fragrance solvent DEP in 70% of fragrance products, at levels up to 2.6% by weight, yet every DEP-positive product was labeled only with the generic term "parfum" — never DEP or any phthalate.
Strong evidence.
Caveats
N=252 individually tested products, Canadian market, 2007-08; detection frequency is lower than two smaller earlier surveys (Hubinger & Havery 2006, EWG 2002) found for fragrances specifically.
Source: Koniecki 2011, Environmental Research 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) adds relevant context but not a measurement: it reports PTFE is used at reported concentrations up to 30% (wider than the 13% cited here from CIR/VCRP), and explicitly classifies PTFE as NOT a PFAA precursor (per Harris 2022), which separates the PFOA/GenX manufacturing-impurity concern in this claim from a different, unrelated mechanism (environmental conversion of other PFAS side chains into PFOA) that Balan 2024 is mainly about. Net effect: no new evidence for or against PFOA/GenX presence in PTFE itself, so strength is unchanged.
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.
Hidden ingredients / Measured in people or real products
Lab tests commissioned by US campaigners found 38 chemicals not listed on the label across 17 popular perfumes; 10 of them had no published safety data at all.
Moderate evidence: NGO report, not peer reviewed; relayed through a student thesis; cite the report itself.
Source: Sarantis et al. 2010 (Not So Sexy), via Gilton 2011 Link to this fact
Hidden ingredients / Lab study (cells or chemistry)
Eight of nine cosmetic UV filters tested were estrogenic in human breast-cancer cells, and six of nine increased uterine weight in immature rats; avobenzone (butyl methoxydibenzoylmethane) was the one inactive in every assay.
Moderate evidence.
Caveats
EC50s 0.68-3.73 uM, low-micromolar and comparable to other xenoestrogens; oral uterotrophic ED50s are 45-934 mg/kg/day, far above cosmetic doses; in-vitro and in-vivo rankings disagree (homosalate and OD-PABA estrogenic in cells, inactive in rats).
Hidden ingredients / Measured in people or real products
In one of the best-known reports linking 'lavender' products to breast growth in children, the boy's violet-water cologne declared no essential oil on its ingredient list; the essential-oil industry's own analysis found none, but reported a synthetic fragrance allergen (alpha-isomethyl ionone), azo dyes and diethyl phthalate, a fragrance solvent suspected of hormone disruption.
Moderate evidence: Industry-funded letter; GC-MS/LC-MS/MS results given as prose with no concentrations, detection limits, lab or sample provenance; not independently confirmed.
Source: Giroux & Orjubin 2020 (JCEM letter; Consortium Huiles Essentielles), The Journal of Clinical Endocrinology & Metabolism Industry-funded Link to this fact
Hidden ingredients / Review of other studies
The only chemical analysis ever published of the products named in the 2019 lavender breast-growth case reports was done by an essential-oil trade group, covered two of the three products and reported no numbers.
Moderate evidence: True of the published literature as read; the NIEHS reply to this letter (dgaa227) has not been read.
Source: Giroux & Orjubin 2020 (JCEM letter; Consortium Huiles Essentielles), The Journal of Clinical Endocrinology & Metabolism Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
In a Belgian test of 10 scented tampons, panty liners and pads, 8 of the 24 fragrance allergens that EU cosmetics must name were found; all 4 tampons and 1 liner held at least one above 10 µg/g, the level at which a cosmetic would have to list it, and none named any allergen on the pack.
Moderate evidence: 10 products from one country (2019); presence in product, not transfer to the body; mostly weak sensitizers at 0.001-0.01%.
Hidden ingredients / Measured in people or real products
The fragrance allergens found most in scented tampons were α-isomethyl ionone (in every tampon, 12.6-19.1 µg/g) and hexyl cinnamal, not the familiar citrus and lavender terpenes.
Moderate evidence: N=4 tampons, Belgian market; limonene/linalool may be under-read by a headspace method that sees parents only.
Hidden ingredients / Review of other studies
FDA's own 1998 registry data, reproduced in full by the industry's cosmetic safety panel, show benzyl alcohol's biggest single cosmetic use was hair dye (130 of 1,572 formulations), with smaller counts in baby shampoo (5 of 21), baby lotion (3 of 53), moisturizers (8 of 769) and body/hand skin care (16 of 796).
Moderate evidence: Voluntary registry counts (Jan 1998); concentration-of-use reporting to FDA had already stopped by 1992 per the same report, so these are presence counts, not amounts used.
Source: Nair 2001 (CIR Expert Panel), International Journal of Toxicology Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
A 2024 lab study of six cosmetics found that ingredient labels can misdescribe the PFAS actually present: one product's named ingredient (a silane) appeared to be a different molecular isomer than the standard, and another's named phosphate-ester ingredient did not disclose that it contained shorter fluorocarbon chain lengths than its name implies.
Moderate evidence: Small sample (6 products from one country, 2 with naming issues); does not establish how common INCI-naming errors are across the wider market.
Source: Namazkar 2024, Environmental Science: Processes & Impacts Link to this fact
Hidden ingredients / Measured in people or real products
Benzyl alcohol, a fragrance allergen dubbed the "covert fragrance," was found in 32 of 533 US baby and children's personal care products (6%) with no "fragrance," "perfume," or "parfum" wording anywhere on the label.
Moderate evidence: Doesn't establish whether these products are marketed "fragrance-free"; measures label wording, not chemical content verification.
Hidden ingredients / Measured in people or real products
Only 16% of the chemicals detected above the testing limit in these hair products were listed anywhere on the product label; fragrance ingredients were almost never named individually, appearing instead as the single word "fragrance".
Moderate evidence: Label concordance rose to 54% only for the highest-concentration chemicals (>1000 ug/g); 28 product/component labels checked.
Hidden ingredients / Animal study
The air freshener's exact formulation is proprietary; GC/MS of its emissions identified toluene, limonene, alpha- and beta-pinene, terpinolene, sabinene and about a dozen other volatiles the consumer has no way to learn about from the label.
Moderate evidence: Qualitative GC/MS of one product, one test atmosphere, recoveries unknown; only peaks with 90%+ library-match certainty reported; brand unnamed.
Source: Anderson & Anderson 1997, Archives of Environmental Health Link to this fact
Hidden ingredients / Measured in people or real products
FDA's own testing of 48 consumer cosmetic products found the fragrance solvent diethyl phthalate (DEP) in all 5 fragrance products tested, at levels up to 38,663 parts per million (3.9% by weight), and in 27 of 48 products overall, though phthalate esters were named on the ingredient list of only some nail products, never on fragrance.
Moderate evidence: Single FDA laboratory, 48 products bought in the Washington DC area (~2003-05), method-validated HPLC-UV; concentration in the product, not absorbed dose.
Source: Hubinger & Havery 2006, Journal of Cosmetic Science Link to this fact
Hidden ingredients / Measured in people or real products
A common personal-care-product ingredient can appear on ingredient labels under several different chemical names (the silicone D5 may be listed as 'cyclopentasiloxane' or 'cyclomethicone'), which may not read as the same substance to a consumer trying to identify or avoid it.
Moderate evidence: Based on this study's own tested product labels and general INCI naming conventions for volatile methyl siloxanes, not a systematic label-disclosure survey.
Source: Coggon 2018, Environmental Science & Technology Link to this fact
Hidden ingredients / Measured in people or real products
Independent laboratory testing not funded by the essential-oil or fragrance industry chemically confirmed that one of these colognes genuinely contained lavender oil (linalool and linalyl acetate), the only time this has been done for an actual implicated product in this literature rather than a reference oil bought for a lab study.
Moderate evidence.
Caveats
Confirms exposure identity for one bottle used by one patient; says nothing about the products used by the other two children in this report, or by any child in other lavender case reports.
Source: Diaz 2016, Journal of Pediatric Endocrinology and Metabolism Link to this fact
Hidden ingredients / Other evidence
California state scientists estimate that the mass of PFAS in cosmetics is concentrated not in makeup but in shaving creams and gels, hair care products, facial cleansers, sun care products, and lotions and moisturizers, which together make up more than 90% of the total estimated PFAS mass in California cosmetics sold each year, while all makeup categories combined make up less than 3%.
Moderate evidence.
Caveats
Estimated from use-concentration ranges compiled from industry websites and patents that the authors say 'differed by orders of magnitude'; the model assumes 100% of PFAS reaches wastewater and exactly one PFAS ingredient per product; total mass estimates span roughly two orders of magnitude (650-56,000 kg/year).
Source: Balan 2024, Environmental Science & Technology Link to this fact
Hidden ingredients / Measured in people or real products
Fragrance materials not known to occur in any natural essential oil were found in products marketed as natural: a 'natural' body lotion contained 0.082% alpha-amylcinnamic aldehyde, a concentration that would require the essential oil itself to be about 16% pure synthetic aldehyde if it came from any known essential oil at typical use levels — evidence the 'natural' formulation included added synthetic fragrance material.
Moderate evidence.
Caveats
Authors' inference from concentration mathematics based on typical perfume-load assumptions, not a direct synthetic-vs-natural-origin test (e.g. isotope-ratio analysis) of the ingredient itself.
Hidden ingredients / Self-reported survey
Only about 1 in 4 Germans (27.5%) know that fragrance chemicals do not have to be fully disclosed on a product's label or safety data sheet.
Moderate evidence: Awareness item, not a measurement of actual disclosure; Germany 2019, n=1,102.
Source: Klaschka 2020a, Environmental Sciences Europe Link to this fact
Hidden ingredients / Measured in people or real products
Acetaldehyde, a possible human carcinogen (IARC Group 2B), was released by 23 of 42 baby products and was never listed on any label.
Weak evidence: Not quantified; may partly form during 40 C incubation.
Source: Nematollahi 2018, Air Quality, Atmosphere & Health Link to this fact
Hidden ingredients / Review of other studies
As early as 2004, a letter in Environmental Health Perspectives warned that fragrances can draw on thousands of chemicals and that most fragranced products had never been tested for human toxicity.
Weak evidence.
Caveats
The '4,000' figure comes from a 1991 book (Ashford & Miller) and describes untested products, not chemicals; later counts run ~3,000. Date 2020, now read as primary, corroborates 'thousands' as the right order of magnitude for the RIFM inventory (~2,600 active + ~3,500 discontinued) and separately states many individual fragrance materials lack toxicity data for standard endpoints — closer to Curtis's 'never tested' claim than any inventory count — but that is about individual chemicals with read-across-fillable data gaps, not about untested products, and does not confirm Curtis's specific '>4,000' figure.
Source: Curtis 2004, Environmental Health Perspectives Link to this fact
Hidden ingredients / Journalism
Laboratory testing commissioned by US campaigners found 38 chemicals not listed on the label across 17 popular fragrances, 14 per product on average, including hormone-disrupting synthetic musks.
Weak evidence: NGO report reproduced in a review; cite Sarantis 2010 directly; primary not in our evidence base.
Source: Sealey 2016 (citing Sarantis 2010, Not So Sexy), Environment International Link to this fact
Hidden ingredients / Other evidence
A 2015 student lab analysis of 12 popular US perfumes and body sprays found 14-33 separate organic chemicals in each product (130 in all), while US law lets the label say just "fragrance".
Weak evidence: Identities are unconfirmed library matches and were never published; counts depend on the detection threshold. Pair with Steinemann 2011 rather than citing alone.
Source: Lee 2015, Young Scientist Journal (Vanderbilt University) Link to this fact
Hidden ingredients / Measured in people or real products
In a university lab test, 3 of 4 cheap generic or dollar-store plug-in air fresheners gave off petroleum-type solvents (alkanes, one with n-hexane) and the fourth was mostly ethanol; none of these adds scent or appears on the package, and the brand-name plug-ins tested showed neither.
Weak evidence: Student journal; one unit per product; identities not confirmed with standards; no amounts measured.
Source: Pino-Delgado 2021 (J Student Res), Journal of Student Research Link to this fact
Hidden ingredients / Government agency
The industry safety panel's own risk calculation for PFOA (a persistent 'forever chemical' associated with PTFE manufacture) in lipstick relies on a single chemical supplier's claim of under 25 parts per billion in the raw material before it is formulated into a product — no actual PTFE-containing lipstick was tested for PFOA.
Weak evidence.
Caveats
The <25 ppb figure and the resulting '755-fold below EPA's advisory' conclusion are worst-case arithmetic on an unverified, pre-formulation raw-material claim, not a measurement of any real cosmetic product.
Source: CIR 2018 Industry-funded Link to this fact
Hidden ingredients / Industry source
PTFE (Teflon) is reportedly used in some cosmetics at concentrations up to 30%, more than double the 13% leave-on maximum cited from the industry-funded Cosmetic Ingredient Review.
Weak evidence.
Caveats
The paper's own use-concentration data for most PFAS ingredients 'differed by orders of magnitude' across sources; the specific source and current-market relevance of the 30% figure could not be verified for this ingest, and it may reflect a patent-claimed rather than marketed formulation.
Source: Balan 2024, Environmental Science & Technology Link to this fact
Information, not medical advice. See also: myths we won’t tell you.