What is Hydroxycitronellal?
Hydroxycitronellal (INCI: Hydroxycitronellal; chemical name: 7-hydroxy-3,7-dimethyloctanal; also called Cyclamen aldehyde) is a synthetic fragrance chemical that provides a distinctive lily-of-the-valley, green floral scent. It is widely used in perfumery for floral compositions — particularly in feminine perfumes and fresh, green fragrance accords. It is also a common ingredient in soap, body care, and household cleaning product formulations.
Hydroxycitronellal is one of the eight components of Fragrance Mix I (FM I), the internationally standardized patch test mixture used to screen for fragrance contact allergy. Its inclusion in FM I reflects its historical significance as a clinically important allergen identified through decades of contact dermatitis research.
Under EU Cosmetics Regulation 1223/2009, hydroxycitronellal is among the 26 fragrance allergens that must be individually declared on cosmetic ingredient labels when present above threshold concentrations. India's INCI labeling conventions follow EU standards, so it should similarly be declared on compliant Indian product labels.
Why does Hydroxycitronellal cause reactions?
Hydroxycitronellal causes Type IV delayed hypersensitivity contact dermatitis. Its aldehyde functional group is reactive toward amino acid residues in skin proteins (particularly lysine), allowing it to form stable haptenic conjugates that the immune system can recognize.
The sensitization rate for hydroxycitronellal in the general population is around 1–3% in fragrance-exposed populations, placing it among the more common fragrance allergens. Co-sensitization with other FM I components is frequent — patients who react to hydroxycitronellal often also react to geraniol, cinnamyl alcohol, or other components.
Where is Hydroxycitronellal found in products?
- Perfumes and colognes: Classic floral and fresh feminine fragrances
- Soap: Very commonly used in floral-scented soap formulations
- Body lotion and shower gel: Green floral product lines
- Household cleaning products: Dishwashing liquids, fabric softeners with floral scents
- Air fresheners: Floral room sprays and plug-ins
How to spot Hydroxycitronellal on labels
- Hydroxycitronellal — INCI name; will appear individually declared on EU-compliant and Indian-compliant cosmetic labels when above threshold
- 7-hydroxy-3,7-dimethyloctanal — IUPAC name (appears in scientific literature and safety data sheets)
In Indian products 🇮🇳
Hydroxycitronellal is found in many fragrance-containing Indian cosmetics and personal care products, particularly in floral-scented soaps, shower gels, and perfumed body lotions. Popular Indian soap brands and body care products with rose, lily, or fresh flower scents are likely sources. Indian-manufactured perfumes and attars using synthetic fragrance compounds may also contain it.
Indian consumers experiencing fragrance-related dermatitis should check for "Hydroxycitronellal" in ingredient lists of fragranced leave-on products used on the face, neck, and hands.
Safer alternatives
- Fragrance-free personal care: Remove all fragranced products from the routine
- Fragrance-free floral alternatives: Some brands create products with light scents from non-allergenic aroma compounds
- Patch testing for specific component: If you react to FM I, individual component testing can identify whether hydroxycitronellal specifically is the culprit vs. other components