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
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Moderate evidence: NGO report, not peer reviewed; relayed through a student thesis; cite the report itself.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 / 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.
Moderate 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. Graded moderate: rests on one product-testing study relayed through a review.
Source: Pastor-Nieto 2021 (Desmedt 2020), Current Treatment Options in Allergy 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
The chemical composition of all five fabric-softener dryer-sheet products tested was undisclosed (a trade secret); gas chromatography/mass spectrometry of one scented brand's emissions found only petroleum-derived aromatic compounds (toluene, styrene, xylenes, trimethylbenzene, isopropylbenzene) plus phenol and thymol — no fragrance terpenes, esters, or alcohols were detected, even though prior published analyses had found such compounds (limonene, linalool, benzyl acetate, and others) in fabric-softener emissions generally.
Moderate evidence.
Caveats
Only one of the five brands was chemically analyzed, and only qualitatively (recovery percentages unknown); about half of the detected GC/MS peaks could not be identified at all, so unidentified compounds — possibly including fragrance materials — cannot be ruled out.
Source: Anderson & Anderson 2000, Journal of Toxicology and Environmental Health, Part A Link to this fact
Hidden ingredients / Journalism
Of the volatile organic compounds identified coming from the dryer vent and the laundry products' own headspace, only ethanol was listed on either product's label or Material Safety Data Sheet.
Moderate evidence: Restates the primary study's disclosure finding (Steinemann 2013); same underlying product as in the 2009 and 2011 Steinemann headspace papers, not an independent product.
Source: Kessler 2011 (EHP Forum), Environmental Health Perspectives Link to this fact
Hidden ingredients / Review of other studies
The word 'parfum' on a cosmetic ingredient list can stand for up to several hundred fragrance chemicals, so a consumer cannot tell whether fragrance allergens beyond the 26 EU-labeled ones are present.
Moderate evidence.
Caveats
The specific 'several hundred' figure is the author's characterization, citing industry practice, not a count from her own data; Nardelli et al. 2011 (cited) found 30 relevant fragrance allergens in specific products, only 18 of which are on the labeled list of 26.
Source: Klaschka 2012, International Journal of Hygiene and Environmental Health Link to this fact
Hidden ingredients / Measured in people or real products
Most healthcare workers using disinfectants did not know whether the products they used contained quaternary ammonium compounds: 99 of 543 subjects (18.2%) could not be classified by exposure status from self-report alone, and researchers had to independently review Material Safety Data Sheets with 3 experts to determine actual product ingredients.
Moderate evidence.
Caveats
This describes a French occupational healthcare-worker population in 2006-2007, not consumers; it does not measure how well consumers can identify QACs in household cleaning products from labels today.
Source: Gonzalez 2014, Clinical & Experimental Allergy Link to this fact
Hidden ingredients / Other evidence
Reading a product's ingredient label does not tell a consumer whether a listed preservative has actually undergone an environmental risk assessment — that status depends on invisible regulatory classification (which EU regulation covers the product category) rather than on anything printed on the package, per a 2016 German household inventory study.
Moderate evidence: Inference from the paper's regulatory-coverage analysis, not a consumer-comprehension study.
Source: Wieck 2016, Environment International Link to this fact
Hidden ingredients / Measured in people or real products
When low-molecular-weight PTFE micropowder (the fine Teflon powder used as a filler and slip agent) is manufactured by gamma-irradiating PTFE in open air, it releases PFOA — a persistent 'forever chemical' — at levels that can exceed the EU's regulatory limit: 28.3 ppb measured after air irradiation, versus a 25 ppb REACH limit that took effect in July 2020.
Moderate evidence.
Caveats
Measured by the manufacturer (Daikin Industries, a major fluoropolymer producer) and Osaka University on laboratory-irradiated PTFE samples, not on a finished consumer or cosmetic product; a single industrial lab's LC-MS measurements, not independently replicated in this evidence base.
Source: Oshima et al. 2020, Scientific Reports Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
Even irradiating PTFE in a vacuum (no oxygen present) still produced up to 25.6 ppb of PFOA at higher radiation doses (400 kGy), right at the EU's regulatory limit, showing that removing atmospheric oxygen during manufacture reduces but does not eliminate PFOA formation.
Moderate evidence.
Caveats
Lower doses (200-300 kGy) in the same vacuum experiment showed no detectable PFOA (below the 5 ppb detection limit); the relationship between dose and PFOA was not perfectly linear (500 kGy gave a lower reading, 19.0 ppb, than 400 kGy's 25.6 ppb) so this is not a simple dose-response curve.
Source: Oshima et al. 2020, Scientific Reports Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
Gamma irradiation traps two kinds of free radicals inside PTFE — one at the broken ends of polymer chains, one within the chain — at roughly a 10:1 ratio; it is specifically the chain-end radicals reacting with oxygen and water after exposure to air that go on to form PFOA, while the more persistent in-chain radicals mostly do not.
Moderate evidence.
Caveats
Mechanistic finding from electron spin resonance (ESR) spectroscopy on lab samples; explains why the manufacturing process works, not a claim about health effects or consumer exposure by itself.
Source: Oshima et al. 2020, Scientific Reports Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
Besides PFOA, gamma-irradiated PTFE also released smaller amounts of related short-chain perfluorocarboxylic acids: about 46 ppb perfluorobutanoic acid (PFBA), 26 ppb perfluoropentanoic acid, 20 ppb perfluorohexanoic acid, and 15 ppb perfluoroheptanoic acid, and, when irradiated in an air-filled sealed bag, a wider range of these acids from 4 to 13 carbons.
Moderate evidence.
Caveats
Measured in laboratory-irradiated PTFE samples, not a finished product; short-chain PFAS are generally considered less bioaccumulative than PFOA but some (e.g. PFHxA) remain under regulatory scrutiny — this evidence base has not separately assessed their toxicology.
Source: Oshima et al. 2020, Scientific Reports Industry-funded Link to this fact
Hidden ingredients / Review of other studies
Unlike most retail candles labeled only "fragrance," the candles in this study had their full wax and fragrance formulations precisely known and reported, because they were purpose-built for the research with fragrance industry cooperation.
Moderate evidence.
Caveats
This transparency applies only to these custom research candles, not to any candle sold at retail; the study does not show that any specific commercial candle's contents are disclosed.
Source: Salthammer 2021, Environment International Industry-funded Link to this fact
Hidden ingredients / Other evidence
A 1998 GC-MS survey of 71 European deodorants found 226 distinct fragrance and non-fragrance chemicals – more than ten times the 21 fragrance substances the same research group had specifically targeted and quantified in a companion study on the same products.
Moderate evidence: Single study, 1998 market snapshot (product formulations have changed since); no concentrations measured for any of the 226 chemicals, only presence/absence by product type.
Source: Rastogi et al. 1998 (Contact Dermatitis 39:293), Contact Dermatitis Link to this fact
Hidden ingredients / Other evidence
Methyl anthranilate, flagged by this 1998 GC-MS/SAR survey as an aromatic amine (a structural class linked to sensitization and other toxicity concerns), was found in 22 of 71 European deodorants tested, a chemical identity a fragrance label would not disclose since it is covered by the generic term 'parfum'.
Moderate evidence: Structural classification, not a clinical allergy finding for this specific compound in this paper; presence only, not concentration.
Source: Rastogi et al. 1998 (Contact Dermatitis 39:293), Contact Dermatitis Link to this fact
Hidden ingredients / Other evidence
Products labeled 'fragrance free' have been shown to still contain fragrance ingredients, used as preservatives, masking perfumes, or botanicals.
Moderate evidence: Secondary citation of Scheinman's clinical observations, not this review's own new data.
Source: Johansen 2003, Am J Clin Dermatol 4(11):789-798, American Journal of Clinical Dermatology Link to this fact
Hidden ingredients / Review of other studies
Fragrance in deodorants and antiperspirants often functions as a deliberate odor-masking ingredient at percent-level concentrations (e.g., linalool combined with dihydromyrcenol at 0.2-1% w/w, or a multi-fragrance blend of musk, skatole, lemon oil, lavender oil, jasmine, vanillin, benzoin, benzyl acetate, and menthol in one patented licorice-root deodorant), separate from and in addition to any anti-microbial active in the same product.
Moderate evidence.
Caveats
Review compiling cosmetics-industry patents and older formulation studies, not new experimental data; the specific listed formulations are patent examples, not necessarily current marketed products.
Source: Kanlayavattanakul & Lourith 2011, International Journal of Cosmetic Science Link to this fact
Hidden ingredients / Review of other studies
Body odor intensity has a genetic component: people carrying the ABCC11 gene variant linked to dry earwax (common in East Asian populations) had less body odor and lower levels of the odor-carrier protein apolipoprotein D than people without it, in the study this review cites.
Moderate evidence.
Caveats
Single cited primary study relayed by this review, not independently verified here; ABCC11's role in foot odor and isovaleric acid formation is separately noted but not from the same study.
Source: Kanlayavattanakul & Lourith 2011, International Journal of Cosmetic Science Link to this fact
Hidden ingredients / Lab study (cells or chemistry)
In a lab test of 25 commercial underarm deodorants, 9 (36%) showed measurable estrogen-like activity in a human breast-cancer-cell assay, concentrated almost entirely in sprays (7 of 10) versus roll-ons (1 of 9) and sticks (1 of 6) from the same product lines.
Moderate evidence.
Caveats
Single lab, single 5-day cell-proliferation assay (E-Screen/MCF-7) per product; no second confirmatory assay, no dermal absorption or human data; the assay is a mixture 'sum parameter' that cannot identify which ingredient(s) drove any one product's result.
Hidden ingredients / Lab study (cells or chemistry)
Testing 62 individually purchased fragrance-related ingredients found in the deodorants, 8 were estrogenic in the same cell assay – including the musk HHCB/galaxolide and benzyl salicylate – at potencies the study describes as comparable to parabens, a preservative class with well-documented weak estrogenic activity.
Moderate evidence.
Caveats
Potencies were 100,000 to 100,000,000 times weaker than estradiol (EC50 3.08×10^-6 to 1.45×10^-4 M; EEF 2.34×10^-8 to 1.15×10^-6); a positive result in this cell assay does not establish that any dose reaches human tissue.
Hidden ingredients / Measured in people or real products
Before candles were lit, the largest class of chemicals detected across the products was esters (30 of 34 dominant compounds identified), which manufacturers disclose on the label only as 'fragrance' or 'aroma oil.'
Moderate evidence.
Caveats
Most of these ester identities were quantified by a predictive (ECN) method rather than authentic calibration standards, so individual concentrations carry more uncertainty than the 24 directly-calibrated target compounds; no specific health hazard was established here for most of the named esters.
Source: Ahn et al. 2015, Journal of Hazardous Materials Link to this fact
Hidden ingredients / Measured in people or real products
329 of 5,588 fragranced cosmetic products (5.9%) named one or more of the 26 EU fragrance allergens on the ingredient list without the words 'parfum', 'fragrance' or 'aroma' also appearing on the label; 45 of these 329 (13.7%) were marketed with 'organic/eco', 'sensitive', 'pure' or 'natural' in the product name.
Moderate evidence: Label survey; whether this reflects deliberate omission or labeling inconsistency by the manufacturer is not determined.
Source: Bennike 2017/2018 Link to this fact
Hidden ingredients / Measured in people or real products
In a 2018 Korean government survey of 482 market deodorants, 18 of 26 screened fragrance allergens and 13 of 27 screened biocidal ingredients were actually detected in the products; some fragrance ingredients reached extreme concentrations in individual products, including benzyl benzoate at 142,344 mg/kg (about 14% of product weight) and thymol at 271,525 mg/kg (about 27% of product weight).
Moderate evidence: Single Korean-market survey (64-482 products depending on the ingredient panel); concentrations are maxima found in specific products, not typical or average levels.
Source: Kim et al. 2018, Science of The Total Environment Link to this fact
Hidden ingredients / Other evidence
Even "unscented" or "fragrance-free" products may contain a perfume or essential oil added specifically to mask the unpleasant odor of the product or its other ingredients.
Moderate evidence: General statement in a narrative review, not a count of how many fragrance-free-labeled products actually contain a masking fragrance.
Source: de Groot 2020, Dermatitis 31(1):13-35, Dermatitis® Link to this fact
Hidden ingredients / Review of other studies
In the EU, an entire perfume or fragrance composition can be declared on the ingredient list as the single word 'parfum' or 'aroma', legally hiding every chemical in it except the handful of allergens that must be named separately.
Moderate evidence: Restates the regulation's text; not new data, and the same point is made by other evidence base sources.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Advocacy group testing
Auditing the printed ingredient lists of 20 popular perfumes sold in Belgium, Denmark, and the Netherlands against 13 official and NGO hazard lists (EDC lists, EU harmonized classifications, the SVHC candidate list, the EU fragrance-allergen list, environmental-persistence lists) turned up 26 problematic substances across the 20 products.
Moderate evidence.
Caveats
Based on declared ingredient lists only, not chemical analysis of the products; every label also carries the undisclosed catch-all 'Parfum', so true chemical content is larger than what was audited.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Advocacy group testing
Only 2 of the 20 tested perfumes contained no suspected endocrine-disrupting chemical (EDC) on their declared ingredient list; the other 18 contained at least one.
Moderate evidence: Counts declared ingredients only; a perfume could contain additional undisclosed EDCs hidden under 'Parfum'.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Animal study
GC-MS of the scented candle's emissions detected methylene chloride (2.71% of peak area, a carcinogen with two known toxic-metabolite pathways) and the phthalate DEHP (0.1%), neither of which would appear on a candle's fragrance or wax label.
Moderate evidence.
Caveats
Detected in headspace/combustion emissions, not necessarily added as ingredients; percentages are of total VOC peak area, not of candle mass, and the specific candle's ingredient list is not published.
Source: Mohamed et al. 2025, Frontiers in Public Health Link to this fact
Hidden ingredients / Measured in people or real products
FDA's 2010 follow-up testing of 84 consumer cosmetic products found the fragrance solvent diethyl phthalate (DEP) in all 11 fragrance products tested (up to 36,006 ug/g, about 3.6% by weight) and in 20 of 60 adult-use products overall, while dibutyl phthalate (DBP) was found only in nail products (11 of 24, up to 62,607 ug/g), even though phthalates carried in as part of 'fragrance' are not required to be named on the label.
Moderate evidence.
Caveats
Single FDA laboratory follow-up survey, 84 products bought in or near Washington DC or online before August 2010 (exact purchase date not stated); HPLC-UV product concentration, not absorbed dose.
Source: Hubinger 2010, Journal of Cosmetic Science Link to this fact
Hidden ingredients / Government agency
The report states that the vast majority of chemicals in current commercial use have never been tested at all for endocrine-disrupting activity, and that unlike active ingredients in pharmaceuticals and pesticides, most materials, articles, and consumer goods are not required to declare their full chemical make-up, leaving many sources of hormone-disrupting exposure simply unknown.
Moderate evidence: General statement about global chemical commerce as a whole, not a count or rule specific to fragrance or personal-care ingredients.
Source: WHO/UNEP 2012 Link to this fact
Hidden ingredients / Review of other studies
"Alum stone" deodorants are potassium alum (Al3K(SO4)2, 12H2O), which does contain aluminum, sometimes marketed under the name "potassium alum" or the misleading "double potassium sulfate," which omits the word aluminum entirely.
Moderate evidence: Single review's characterization of marketing language, not a systematic label survey.
Source: Martini 2020, Annales de Dermatologie et de Vénéréologie Link to this fact
Hidden ingredients / Measured in people or real products
Hormone-disrupting chemicals in household cleaners, synthetic detergents, fabric softeners, air fresheners, and deodorants are almost always added as fragrance or preservative, not as the product's main ingredient, so their presence rarely shows up as a headline ingredient a shopper would notice.
Moderate evidence: Based on a database of listed ingredients matched to EPA hazard flags, not chemical measurement of the actual products; a single country's product registry (South Korea, 2020).
Source: Lee & Ji 2022, Ecotoxicology and Environmental Safety Link to this fact
Hidden ingredients / Measured in people or real products
Certain hormone-disrupting chemicals recur together on the same product's ingredient list more often than chance: benzisothiazolinone with hexyl cinnamaldehyde in synthetic detergents, and the fragrance chemical Lilial (butylphenyl methylpropional) with citronellol in fabric softeners, identified by mining co-occurrence patterns across thousands of Korean household products.
Moderate evidence: Association-rule mining measures how often chemicals are listed together on ingredient lists, not their combined toxicity or exposure when the product is used.
Source: Lee & Ji 2022, Ecotoxicology and Environmental Safety Link to this fact
Hidden ingredients / Government agency
DEA and its condensates (cocamide DEA, lauramide DEA) are not banned from cosmetics, but US Cosmetic Ingredient Review guidance says they should not be combined with nitrite or other nitrosating agents in a formulation, because that reaction can form N-nitrosodiethanolamine (NDELA), an animal carcinogen that is not itself listed on any ingredient label.
Moderate evidence.
Caveats
This paper restates the regulatory rationale (citing 1983/1986 CIR positions) but does not itself measure NDELA formation in any tested product; the formation-measurement gap is still open in our evidence base.
Source: Kraeling 2004, Food and Chemical Toxicology Link to this fact
Hidden ingredients / Measured in people or real products
A 2007 NRDC test found one or more of five phthalate esters (DBP, DEP, DIBP, DIHP, DMP) in 12 of 14 US air fresheners, including some labeled all-natural or unscented, and none of the 12 positive products listed phthalates as an ingredient on the label.
Moderate evidence.
Caveats
Small sample (14 products), not independently replicated in this evidence base; NRDC's primary report is not yet a evidence base source. Nearly 20 years old; current formulations may differ.
Source: EPA 2007, citing NRDC 2007 Link to this fact
Hidden ingredients / Measured in people or real products
In the 2007 NRDC air-freshener test, diethyl phthalate (DEP) was the phthalate found at the highest concentrations: three samples at 360, 1,100 and 7,300 ppm, and six more samples at 6.3 ppm or less; di-n-butyl phthalate (DBP), the only one of the five on California's Proposition 65 reproductive-toxicity list, was found at much lower levels (four samples under 1 ppm, one at 4.5 ppm).
Moderate evidence.
Caveats
Reported by EPA to more decimal/sample-level detail than the secondhand 2017 review citation already in our evidence base; NRDC's own report remains unverified as a evidence base primary.
Source: EPA 2007, citing NRDC 2007 Link to this fact
Hidden ingredients / Government agency
Benzophenone migrates into food from UV-cured printing inks on paperboard packaging even without direct contact — including through frozen storage at -20C and via the vapor phase from secondary packaging — and the UK Food Standards Agency estimated high-level adult dietary exposure at 1.2-1.5 micrograms/kg body weight per day.
Moderate evidence: Exposure estimate combines a 97.5th-percentile high-consumption food-frequency scenario with average measured occurrence levels, not a direct biomonitoring measurement.
Source: IARC 2013 Link to this fact
Hidden ingredients / Measured in people or real products
Styrene migrates from polystyrene food-contact packaging into food; US dietary intake from this route has been estimated at roughly 9 micrograms per day (Lickly et al. 1995), with strawberries and avocados showing the highest detected styrene concentrations in an FDA Total Diet Study of 70 foods.
Moderate evidence.
Caveats
Modeling-based estimate combining migration data and consumption factors, not a direct measurement of total dietary intake in a real population; food styrene can also arise from natural/other sources, not only packaging migration.
Source: IARC 2019 (Vol. 121) Link to this fact
Hidden ingredients / Government agency
EPA lists moth repellents and air fresheners among household-product sources of organic-gas (VOC) indoor air pollution, and notes that paradichlorobenzene, a chemical carrying an 'avoid breathing vapors' warning on moth-repellent labels, is also the key active ingredient in many air fresheners.
Moderate evidence: EPA names the shared ingredient and the moth-repellent warning; it does not separately assess air-freshener-specific health risk.
Source: US EPA, "The Inside Story" Link to this fact
Hidden ingredients / Measured in people or real products
In a database analysis of Korean household chemical products, the most prevalent chemicals flagged as endocrine disruptors were compounds added as fragrance ingredients or preservatives (e.g. linalool, D-limonene, hexyl cinnamaldehyde), not the product's main functional ingredient.
Moderate evidence.
Caveats
Ingredient-list matching against EPA CompTox/ToxCast hazard flags, not measured concentrations or confirmed toxicity in the products as sold; single-country (South Korea) database of household chemical products (air fresheners, cleaners, detergents, fabric softeners, deodorants), not personal-care/cosmetic products specifically.
Source: Lee & Ji 2022, Ecotoxicology and Environmental Safety Link to this fact
Hidden ingredients / Measured in people or real products
Diethyl phthalate (DEP), the phthalate most often found in fragrance products, most likely comes from the fragrance ingredient itself, where it functions as a solvent and fixative rather than from another use in the formulation.
Moderate evidence.
Caveats
This is the authors' interpretive conclusion drawn from DEP's concentration pattern across product categories (highest in fragrance products, by far), not a direct mechanistic test of fragrance-longevity. The 'fixative' function (slowing evaporation of more volatile scent components, making scent last longer) is standard perfumery-formulation terminology, consistent across sources, but this specific single 2006 FDA study is the only one in our evidence base that states the fixative role explicitly; the fragrance-concentration finding itself is independently replicated by two other surveys (Koniecki 2011, Dodson 2012) already in our evidence base.
Source: Hubinger & Havery 2006, Journal of Cosmetic Science Link to this fact
Hidden ingredients / Review of other studies
An FDA laboratory survey concluded that phthalate esters found in most cosmetic products most likely enter via the fragrance ingredient itself, where they function as a solvent/fixative rather than for some other purpose.
Moderate evidence.
Caveats
This is the study authors' own interpretive conclusion (source attribution), not a direct measurement of fixative function or of scent longevity; it is consistent with, but does not by itself prove, the specific mechanism that phthalates make fragrance 'last longer'. Based on a single FDA survey (n=48 products, 2006), though its DEP findings are independently corroborated by later, larger surveys (Koniecki 2011, n=252).
Source: Hubinger & Havery 2006, Journal of Cosmetic Science Link to this fact
Hidden ingredients / Measured in people or real products
This industry-funded skin-irritation study of 24 detergent formulations reports no fragrance or enzyme content for any tested product; formulation details, including whether products were fragranced or enzyme-containing, are described only as 'available upon request' from the funding trade association, not disclosed in the published paper.
Moderate evidence: Absence of disclosure in a single paper; cannot confirm whether fragrance/enzyme content varied across the 24 formulations or influenced the irritation results.
Source: Robinson et al. 2005, Food and Chemical Toxicology Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
Electron microscopy found nanosized particles or nanostructures in two spray products that were NOT labeled or marketed as nanotechnology-based (a regular silver spray and a regular disinfectant spray), while three products that WERE labeled nanotechnology-based (facial, hair, and skin-hydrating sprays) showed no detectable particles or structures under the same microscopy.
Moderate evidence: Morphological/TEM evidence only, not chemical confirmation of nanomaterial identity; single-lab study of 10 products.
Source: Nazarenko 2014, Environmental Science: Nano Link to this fact
Hidden ingredients / Measured in people or real products
In a 2007 NRDC lab test, none of 14 US air fresheners listed phthalates as an ingredient on the label, and 10 of the 14 listed no ingredients at all.
Moderate evidence: Single lab, one sample per product, not peer reviewed or independently replicated since 2007.
Source: NRDC 2007, Clearing the Air Link to this fact
Information, not medical advice. See also: myths we won’t tell you.