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.
Skin allergy / Measured in people or real products
In a clinical study of 658 hand-eczema patients across 3 European centers, 67 (10.2%) reacted on patch testing to at least one fragrance chemical selected because it is common in household cleaning and personal-care products used on the hands.
Strong evidence: Clinic-referred hand-eczema population (3 tertiary centers), not a random sample of the general public.
Source: Heydorn 2003, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In industry's own comparative testing of 24 household cleaning-product formulations, liquid and powder laundry and dish detergents ranked among the least skin-irritating categories tested, below a standard 20% SDS irritant benchmark (liquid laundry detergent TR50 average 3.48 h; powder laundry and dish detergents >16 h, vs. SDS's 1.81 h).
Moderate evidence.
Caveats
Irritation (erythema from a single undiluted, fully occluded 4-h exposure), not allergy; single industry-funded study series with no independent replication; authors state results should not be extrapolated to real-use exposure conditions.
Source: Robinson et al. 2005, Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Other evidence
Household detergents and cleaners were preserved with MI far more often than cosmetics in two European surveys: 16 of 97 Swedish detergents (16.5%) against 1 of 204 cosmetics, and 30 of 291 Italian cleaning products (10.3%).
Moderate evidence: Secondary summary of ingredient-label surveys from about 2009-2010; counts are small and not recent.
Source: Lundov 2011, British Journal of Dermatology Link to this fact
Skin allergy / Other evidence
US dermatologists' society review: fragrance was the 2007 Allergen of the Year; the industry's RIFM database lists more than 2,800 fragrance ingredients, at least 100 of them known allergens, and fragrance allergens can be hidden in cleaning and cosmetic products, even ones marketed as fragrance free.
Moderate evidence: Narrative review relaying other papers' statements; no original data and no counts of products.
Source: Militello 2020, Dermatologic Clinics Link to this fact
Skin allergy / Other evidence
EWG Verified cleaners must label 26 fragrance allergens on the package at 0.01 percent (0.001 percent for hand dish soap, hand laundry detergent, and leave-on pet products), and post about 57 more on the product website.
Moderate evidence: The on-pack list is the pre-2023 EU 26; current EU cosmetics law requires about 80 on pack. The website list has a one-year phase-in and EWG reserves a transition period.
Source: EWG Verified criteria for cleaning products (10.24), Environmental Working Group, 2024 Link to this fact
Skin allergy / Other evidence
Scented laundry and cleaning products (hair-styling products, laundry detergent, fabric softener, usually floral-scented) formed one group of odors migraine patients named, and chronic migraine patients named this group more often than episodic patients (P = 0.037).
Weak evidence.
Caveats
Only 16 chronic patients, no correction for multiple tests, and the paper's own percentages do not reconcile; cross-sectional, so it cannot show that chronic migraine increases sensitivity.
Information, not medical advice. See also: myths we won’t tell you.