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.
Fragrance is everywhere / Measured in people or real products
Besides the fragrance-mix allergens, 14 other common fragrance materials (including linalool, benzyl acetate, and hedione) were found in 40-97% of the 73 deodorants tested in 1996; for three of them (hedione, linalyl acetate, alpha-isomethyl ionone) no published human contact-allergy case existed at the time despite their widespread use.
Moderate evidence.
Caveats
Absence of published reports as of 1998 is not the same as absence of risk; testing history for these three substances specifically was not systematically reviewed by the authors beyond a literature check.
Source: Rastogi et al. 1998, Contact Dermatitis Link to this fact
Fragrance is everywhere / Government agency
Alpha-isomethyl ionone, an allergen on the EU's 1999 labeled list, was declared on 46.6% of 88 deodorants checked in 2007 and detected in about 65% of 23 analyzed deodorants (6-2,588 ppm); it was found in 21.7% of 516 consumer products in another survey.
Weak evidence.
Caveats
Small, older market surveys cited from other authors (German/Danish samples); label-declaration frequency, not exposure; the underlying patch-test rates for this chemical are low (0-2.1%).
Information, not medical advice. See also: myths we won’t tell you.