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 / 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 / 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 / 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 / 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 / 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 / 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
Information, not medical advice. See also: myths we won’t tell you.