Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
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
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 / 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
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 / Journalism
A low Skin Deep hazard score can simply mean little is known: missing toxicity data carries zero weight in the hazard score, and EWG advises choosing products with low hazard AND at least "fair" data availability.
Strong evidence: EWG's own advice and weighting table. The data-availability rating is built half from PubMed study counts, so heavily studied ingredients rate higher regardless of safety.
Source: EWG Skin Deep methodology page (2026 capture) Link to this fact
Hidden ingredients / Other evidence
The CIR draft says 1,4-dioxane, a known animal carcinogen, can contaminate ethoxylated ingredients such as polysorbates and that industry 'reported that it is aware' of it and uses 'additional purification steps' (polysorbates are steam-stripped), but it reports no measured 1,4-dioxane or ethylene oxide levels.
Strong evidence: The absence of numbers is a fact about this draft only; other sources may hold specifications or FDA measurements.
Source: CIR 2015 draft Industry-funded Link to this fact
Hidden ingredients / Other evidence
In IARC's 2018 list, titanium dioxide (Vols 47, 93, 2010), carbon black (2010), diethanolamine (2013) and coconut oil diethanolamine condensate, the cocamide DEA surfactant (Vol 101, 2013), were each printed as Group 2B, possibly carcinogenic to humans.
Strong evidence: 2018 snapshot; 2B is limited evidence; hazard not risk; the list does not give exposure from any product.
Source: IARC 2018, Agents Classified by the IARC Monographs, Vols 1-123 Link to this fact
Hidden ingredients / Other evidence
The 2018 list printed talc without asbestos or asbestiform fibers as Group 3 and perineal use of talc-based body powder as 2B (Vol 93, 2010), with a note that asbestos-containing talc should be regarded as carcinogenic to humans.
Strong evidence: Superseded in part: talc was reclassified in 2024 (Vol 136); this page records only the 2018 printed status.
Source: IARC 2018, Agents Classified by the IARC Monographs, Vols 1-123 Link to this fact
Information, not medical advice. See also: myths we won’t tell you.