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Hydroxyisohexyl 3-cyclohexene Carboxaldehyde in skincare
HICC / Lyral. BANNED in EU since 2021 due to potent sensitization. Originally one of the EU 26 allergens; now prohibited.
BANNED in the EU since August 2021 due to high sensitization rates. If found in a product, it indicates non-EU-compliant or pre-ban stock. Originally one of the EU 26 mandatory fragrance allergens. Still permitted in some non-EU markets. Avoid all products containing this ingredient.
What it is
Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde (HICC, trade name Lyral) was a widely used synthetic fragrance with a sweet, floral, lily-of-the-valley scent. Originally one of the 26 fragrance allergens requiring mandatory declaration under EU Cosmetics Regulation 1223/2009. However, due to its very high sensitization rate (~2–5% in patch-tested populations, among the highest of all fragrance allergens), the EU banned HICC from all cosmetic products effective August 23, 2021 (Commission Regulation EU 2019/831). Products containing HICC are non-compliant in the EU. Still permitted in some non-EU markets (US, parts of Asia). Individuals with any fragrance sensitivity should strictly avoid.
The facts
| Category | Fragrance Allergen (Aldehyde). EU BANNED |
| Typical use | Morning and evening |
| Concentration YARAI treats as a full dose | 0% |
| EU Cosmetics Regulation annex | II |
| EU status | prohibited |
| EU and US differ | No FDA restriction. Still used in US fragrances. |
Why the amount matters, not just the presence
Most ingredient checkers tell you whether something is in the bottle. That is a smaller question than it sounds. Hydroxyisohexyl 3-cyclohexene Carboxaldehyde at 0% and hydroxyisohexyl 3-cyclohexene carboxaldehyde at a trace level are not the same ingredient in any way that affects your skin.
An ingredient list is ordered by quantity, so position carries real information. YARAI reads that position and scores accordingly, which is why the same ingredient can land differently in two different products.
The honest limit: a list gives order, not percentages. Estimating concentration from position is an estimate. It is a better estimate than ignoring position, and it is still an estimate. We would rather tell you that than let a number look more certain than it is.
Regulatory status
Banned in EU cosmetics (Annex II) since August 2017 (HICC / Lyral). SCCS found it to be a strong contact allergen with no safe-use threshold.
Common questions
What does hydroxyisohexyl 3-cyclohexene carboxaldehyde do in a skincare product?
HICC / Lyral. BANNED in EU since 2021 due to potent sensitization. Originally one of the EU 26 allergens; now prohibited.
How much hydroxyisohexyl 3-cyclohexene carboxaldehyde should a product contain?
YARAI treats 0% as a full dose for this ingredient. Below that, the ingredient is present but is scored as contributing less. An ingredient list gives you the order of ingredients, not their percentages, so this is an estimate read from position rather than a measurement.
When should I use hydroxyisohexyl 3-cyclohexene carboxaldehyde?
BANNED in the EU since August 2021 due to high sensitization rates. If found in a product, it indicates non-EU-compliant or pre-ban stock. Originally one of the EU 26 mandatory fragrance allergens. Still permitted in some non-EU markets. Avoid all products containing this ingredient.
Check your own products
Point your camera at a product. YARAI identifies it from the label, finds that product's full ingredient list from published sources, and scores it. No barcode and no box needed, which is how it handles imported and small-brand products.
Concern level, category and thresholds on this page are read directly from the same data the YARAI app scores with, so this page and the app cannot disagree. EU figures cite Regulation (EC) No 1223/2009. Last built 2026-09-09. Nothing here is medical advice.