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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 / Government agency
Alpha-isomethyl ionone ranks as an established human contact allergen in the EU opinion (category ++, 11-100 reported cases), but individual patch-test studies found positive rates of 0% to 2.1%, and the industry's own review lists four negative human induction tests.
Weak evidence: Low case counts and low prevalence; the industry review is the industry's position; the ++ rating partly reflects how often it has been tested.
Information, not medical advice. See also: myths we won’t tell you.