Geraniol
Also known as Geraniol, (2E)-3,7-Dimethyl-2,6-octadien-1-ol, trans-3,7-Dimethyl-2,6-octadien-1-ol, (E)-Geraniol
“EU SCCS says: restricted.”
Geraniol is a monoterpene alcohol used as a fragrance ingredient, naturally occurring in rose, palmarosa, citronella, and many essential oils. It is one of the original 26 EU fragrance allergens of mandatory disclosure under EU Regulation 1223/2009 Annex III (Entry 78), requiring label declaration above 0.001% in leave-on products or 0.01% in rinse-off products. SCCS Opinion 1459/11 (December 2011) classified Geraniol in allergenicity tier +++ (101-1000 documented patch-test reactions), placing it among established human contact allergens alongside Cinnamal, Citral, Coumarin, Eugenol, Farnesol, Hydroxycitronellal, and Isoeugenol. The 2022 RIFM safety assessment (Api et al., Food Chem Toxicol 167 Suppl 1) concluded geraniol use as a fragrance ingredient is supported by existing data with a No Expected Sensitization Induction Level (NESIL) of 11000 μg/cm², not genotoxic, MoE >100 for repeated-dose and reproductive endpoints, not phototoxic. PubMed evidence (Hagvall et al. 2007, 2012, 2018) demonstrates geraniol functions as a pre-hapten and pro-hapten — autoxidation in air forms hydroperoxides, geranial, and neral (the actual sensitizers), and skin metabolism produces analogous reactive species. The 2018 Swedish multicentre study (n=1,476 dermatitis patients) found 8% positive patch reactions to oxidized geraniol at 11% test concentration vs only 1% to pure geraniol at 6%, confirming that oxidation products drive most clinical sensitization. CIR has not issued a standalone safety assessment for Geraniol — fragrance ingredients are typically deferred to RIFM by CIR practice; Geraniol is referenced as a sensitizing constituent in CIR botanical group assessments (e.g., Rosa damascena 2022, Rosa centifolia 2023).
Widely used natural fragrance ingredient providing characteristic rose-floral, sweet, and slightly citrus odor notes; principal odor component of rose oil and palmarosa oil
Naturally occurring constituent of geranium, rose, palmarosa, citronella, and lemongrass essential oils — used in fragrance formulations targeting natural-product positioning
RIFM 2022 NESIL of 11000 μg/cm² provides quantitative skin sensitization induction threshold for QRA-based formulation; concentrations below this with appropriate antioxidant protection can be designed to be non-sensitizing
RIFM 2022 confirmed not genotoxic, not phototoxic/photoallergenic, MoE >100 for systemic toxicity at typical fragrance use concentrations
- · Regulated EU fragrance allergen (Annex III Entry 78): label declaration mandatory above 0.001% (leave-on) or 0.01% (rinse-off) due to documented sensitization in susceptible individuals
- · SCCS/1459/11 allergenicity tier +++ (101-1000 reported reactions): Geraniol is an established contact allergen in humans, ranked among the higher-prevalence fragrance sensitizers
- · Cross-reactivity with citral (geranial+neral mixture) and geranyl acetate documented — patch-test positive patients to one terpene-aldehyde commonly react to others in the metabolic chain
Pre-hapten/pro-hapten dual-pathway activation: pure geraniol has weak intrinsic sensitization potency, but autoxidation in air (during product storage and use) produces hydroperoxides, geranial, and neral that are the actual clinical sensitizers — formulators must consider antioxidant systems and shelf-life storage stability
Oxidized geraniol patch-test prevalence (8% at 11% conc., Swedish 2018 multicentre study) substantially exceeds pure geraniol prevalence (1%) — most clinical sensitization in real consumers is to oxidation products formed in product, not the pure ingredient
No standalone CIR safety assessment exists (fragrances deferred to RIFM by CIR practice); regulatory weight rests on SCCS opinion and EU Annex III listing, with RIFM 2022 update providing toxicology endpoints
SCCS/1459/11 Opinion on Fragrance Allergens in Cosmetic Products (adopted 13-14 December 2011) — Geraniol (CAS 106-24-1) classified as es…
“GERANIOL 106-24-1 +++”— sccs_o_073.pdf, Table 13-1 (Established contact allergens in humans)
EU Regulation 1223/2009 Annex III (Restricted Substances) — Entry 78: Geraniol, CAS 106-24-1; fragrance allergen labeling required above …
“Entry 78, Geraniol, CAS 106-24-1, EC 203-377-1; the presence of the substance must be indicated in the list of ingredients referred to in Article 19(1)(g) when its concentration exceeds 0,001 % in leave-on products or 0,01 % in rinse-off products”— EU Reg 1223/2009 Annex III, Entry 78