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 / 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 / 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
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 / 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 / Review of other studies
d-Limonene, a common fragrance/scent chemical, was detected in 100% of personal and area air samples in 7 nail salons despite not appearing as an ingredient on any safety data sheet the authors reviewed for the nail products used there.
Moderate evidence.
Caveats
Authors could not identify the actual source (possible fragrance classification, or an unreviewed product category such as lotions, scrubs, waxes or cleaning products); small pilot (7 salons).
Hidden ingredients / Measured in people or real products
Di(2-ethylhexyl) phthalate (DEHP), a plasticizer used to make nail polish more flexible and durable, was the most abundant of six phthalates measured on silicone wristbands in all 10 nail salons tested (median 391.80 ng/g-wristband), with diethyl phthalate (DEP) second highest (median 154.4 ng/g-wristband) — but the paper never discusses what produces its measured DEP, unlike its explicit attribution of DEHP to nail polish and d-limonene to cleaning/fragrance products.
Moderate evidence.
Caveats
Small sample (n=10 for phthalates); wristband measurement is a sorbed dose, not a direct air concentration; the paper's own figures and Discussion text mislabel this unit as ppb instead of the Methods/footnote's ng/g-wristband, an internal inconsistency in the published article.
Source: Han et al. 2022 Link to this fact
Hidden ingredients / Animal study
In a Dutch government study, isoeugenol was the only one of five skin-allergy fragrance chemicals to stimulate the lymph nodes of mice that breathed it (about 7-fold more cell growth after 6 hours a day for 3 days), while limonene and linalool did not.
Moderate evidence.
Caveats
Mice (6 per group), one lab, nose-only at 75 mg/m3, an unvalidated assay tested mostly on strong sensitizers; a hazard signal, not human disease. Government-funded (NVWA), no industry money declared.
Source: ter Burg 2014, Inhalation Toxicology Link to this fact
Hidden ingredients / Other evidence
Many chemicals on the founding 1965 FEMA flavor list are also common fragrance ingredients or labeled contact allergens, among them eugenol, isoeugenol, cinnamaldehyde, citral, linalool, geraniol, hydroxycitronellal, and d-limonene; the list covers eating them at the reported food levels, not breathing or skin contact.
Moderate evidence: FEMA numbers read from scanned OCR and checked on the page image only for eugenol and methyl eugenol; the paper does not discuss fragrance use.
Source: Hall & Oser 1965 (FEMA GRAS 3), Food Technology Industry-funded Link to this fact
Hidden ingredients / Other evidence
Wet cleaning rests on water, but the detergents and spotting agents hold alcohol ethoxylates, glycol ethers, D-limonene, monoethanolamine, quaternary ammonia and trade secrets; many safety data sheets lacked ingredient data, some noted skin and eye irritation, and ethoxylated alcohols can carry 1,4-dioxane (county study pending).
Moderate evidence: From the county's review of a sample of safety data sheets, not testing of products or garments; the report still rated wet cleaning health-green.
Source: SCDHS 2018 Link to this fact
Hidden ingredients / Other evidence
The hydroperoxides that cause this allergy are not listed on labels, so patients can only look for limonene and linalool, two of the 26 EU-declarable fragrance allergens.
Moderate evidence: Authors' statement about labeling in the EU; limonene and linalool on a label show the parent chemical, not whether any hydroperoxide is present.
Source: Dittmar & Schuttelaar 2019, Contact Dermatitis Link to this fact
Hidden ingredients / Other evidence
Limonene, linalool and Lyral are fragrance ingredients commonly found in personal care products, processed foods and beverages, and perfumes, and the society judges them relevant for many patch-tested patients.
Moderate evidence: Committee judgment based on cited reviews; no product-survey data in this paper.
Hidden ingredients / Other evidence
The fragrance terpenes in the restroom's urinal screens (alpha-terpinene, linalool, limonene, linalyl acetate and others, about 20 ppb total in one test) were the main chemicals that reacted with the lamp-made ozone.
Moderate evidence: Single room; deodorizer screens, not household fragrance; alpha-terpinene dominance is specific to this product.
Source: Link 2024, Environmental Science: Processes & Impacts Link to this fact
Hidden ingredients / Other evidence
Limonene and beta-pinene scent terpenes were measurable in every perfume, deodorant and cleaning liquid tested (about 0.1-0.3% and 0.04-0.65% of product weight), even though labels only say 'fragrance' or, for the cleaners, name limonene.
Moderate evidence.
Caveats
Six products; GC-MS of three terpenes only, so other scent chemicals are unmeasured; alpha-pinene was below the detection range. The abstract's beta-pinene range (0.4-0.7%) differs from Table 1 (0.04-0.65%).
Information, not medical advice. See also: myths we won’t tell you.