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Hydroxycitronellal in skincare
Lily-of-the-valley scent; one of the more potent fragrance sensitizers. EU-mandated allergen disclosure above threshold.
Found in both AM and PM scented products, particularly floral-scented formulations. PM leave-on products carry higher sensitization risk. One of the stronger sensitizers among the EU 26 mandatory fragrance allergens.
What it is
Hydroxycitronellal (7-hydroxycitronellal, 7-hydroxy-3,7-dimethyloctanal) is a synthetic fragrance aldehyde with a sweet, lily-of-the-valley, muguet-like scent, widely used in floral fragrances. One of the 26 fragrance allergens requiring mandatory individual declaration under EU Cosmetics Regulation 1223/2009 Annex III if present above 0.001% in leave-on products or 0.01% in rinse-off products. Among the more potent contact sensitizers in the EU 26 list. Sensitization rate ~1–3% in patch-tested populations. The EU SCCS has specifically noted hydroxycitronellal as a fragrance allergen warranting particular caution.
The facts
| Category | Fragrance Allergen (Aldehyde) |
| Typical use | Morning and evening |
| Concentration YARAI treats as a full dose | 1% |
| EU maximum permitted concentration | 1.0% (1.0%) |
| EU Cosmetics Regulation annex | III |
| EU status | restricted |
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. Hydroxycitronellal at 1% and hydroxycitronellal 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
EU Annex III restricted fragrance allergen: max 1.0% in leave-on and rinse-off.
Common questions
What does hydroxycitronellal do in a skincare product?
Lily-of-the-valley scent; one of the more potent fragrance sensitizers. EU-mandated allergen disclosure above threshold.
How much hydroxycitronellal should a product contain?
YARAI treats 1% 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.
Is hydroxycitronellal restricted in the EU?
The EU Cosmetics Regulation permits this ingredient up to 1.0% in leave-on cosmetics, listed under III. 1.0%
When should I use hydroxycitronellal?
Found in both AM and PM scented products, particularly floral-scented formulations. PM leave-on products carry higher sensitization risk. One of the stronger sensitizers among the EU 26 mandatory fragrance allergens.
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.