Cited skincare — every flag names its source, no upsell.
Hy

Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde

Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde · Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde (Lyral) · Hydroxymethylpentylcyclohexenecarboxaldehyde

A lily-of-the-valley scent banned in the EU, because it was one of the most common causes of fragrance allergy.

What it does

It was used for its lily-of-the-valley scent and was one of the most common causes of fragrance allergy in European patch tests. The EU banned it: no new products from August 2019 and none on shelves from August 2021. Products made for other markets, or before the ban, can still list it.

The EU’s ingredient database lists it as a fragrance (adds scent).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗

The evidence, graded

expert consensusTreemoss (Evernia furfuracea), oakmoss (Evernia prunastri) and HICC (Lyral) were the three most frequent allergens when a Copenhagen clinic patch-tested 1,508 eczema patients with each of the EU's 26 labeled fragrance allergens. Commission Regulation (EU) 2017/1410 prohibited HICC, and atranol and chloroatranol, from 23 August 2019 for new EU products and 23 August 2021 for stock on EU shelves. Those two are the mosses' main allergens.Heisterberg 2011 · Contact Dermatitis ↗

Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.

Also known as

lyral, HICC

Browse all 1238 ingredients — grouped by what they do, each with whatever evidence we can cite.

This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
Want more like this?
Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.
See what Drop doesHow Drop works