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 Belgium, about 1 in 10 topical (skin-applied) pharmaceutical products, wound-healing ointments, NSAID gels, antiseptics, antihemorrhoidals, even corticosteroid-antibiotic creams, listed a fragrance ingredient, sometimes disclosed only as the single word "Perfume".
Strong evidence: 370/3,820 products in a Belgian label survey (2009); a label/composition survey, not chemical analysis; historical product list, not a current market snapshot.
Hidden ingredients / Measured in people or real products
A single undisclosed "Perfume" in one antibiotic-corticosteroid cream (Mycolog/Triadcortyl) caused allergic reactions in 34 patients, more than any other product in a 30-year clinic series, and its 28-ingredient composition was only obtained by directly asking the manufacturer, not from the label.
Strong evidence: Single-clinic case series; one product's undisclosed formula, not a general claim about all perfume-labeled products.
Information, not medical advice. See also: myths we won’t tell you.