Hexyl Cinnamal
Also known as Hexyl Cinnamal, Hexyl cinnamaldehyde, alpha-Hexylcinnamaldehyde, alpha-Hexyl cinnamic aldehyde, AHCA, 2-Benzylideneoctanal, 2-(phenylmethylene)octanal
“EU SCCS says: restricted.”
Hexyl Cinnamal (alpha-hexylcinnamaldehyde, CAS 101-86-0, C15H20O) is a synthetic aromatic aldehyde with a jasmine-like odor used widely in fine fragrance and personal care. EU Regulation 1223/2009 Annex III Entry 87 lists it as one of the 26 originally regulated fragrance allergens, requiring label disclosure when concentration exceeds 0,001% in leave-on or 0,01% in rinse-off products (confirmed unchanged by Reg (EU) 2023/1545). SCCS/1459/11 (2012) classifies HEXYL CINNAMAL as an established contact allergen in humans (Table 13-1) with rating ++ — i.e., 10-100 published positive patch test cases — placing it among the lower-tier sensitizers (vs. +++ for Cinnamal/Citral/Limonene-oxidised and ++++ for HICC). It appears in opinion List B (less frequently reported allergens) and is NOT categorised as a prehapten in Table 13-6 (no autoxidation activation pathway). Hexyl Cinnamal has been a constituent of Fragrance Mix II (FM II) since Frosch et al. 2005 (Contact Dermatitis 52:216-225; PMID 15859994), tested at 5% in petrolatum, where AHCA ranked among the five most reactive constituents but with lower prevalence than HICC, citral, farnesol, or citronellol. Basketter et al. 2015 (Cutan Ocul Toxicol; PMID 24988491) characterizes it as a 'weaker skin sensitizer than predicted by LLNA' — historically used as a regulatory positive control precisely because of low-to-moderate human sensitization potency. Clinical case reports (Rubio-González 2015, PMID 25109769) confirm individual sensitization with cross-reactivity to cinnamaldehyde. CIR has NOT published a standalone safety assessment — verified absent from QRT-122017revised072018.pdf (alphabetical traversal: Hexamethylindanopyran → Hexyl Isostearate → Hexyl Laurate → Hexyl Methacrylate → Hexyl Methicone → Hexyldeceth-2; no 'Hexyl Cinnamal' or 'Hexyl Cinnamaldehyde' row exists). Per CIR policy, fragrance-only ingredients are deferred to RIFM Expert Panel (REXPAN) and IFRA Standards (IFRA Standard 49 governs hexyl cinnamic aldehyde use; Amendment 49 dated 2020). No PubMed-indexed Api/RIFM standalone safety assessment exists for hexyl cinnamic aldehyde — only RIFM internal report numbers (e.g., 55866) are referenced externally.
Provides characteristic jasmine-floral fragrance note widely used in fine perfumery, personal care, and household products.
Basketter et al. 2015 characterizes hexyl cinnamal as a 'weaker skin sensitizer than predicted by murine LLNA' — its historical use as a regulatory positive control reflects its low-to-moderate (rather than strong) human sensitization potency.
Not classified as a prehapten in SCCS Table 13-6 (no autoxidation activation pathway documented), distinguishing it from limonene/linalool/geraniol prehapten allergens — formulation shelf-life less likely to amplify sensitization risk via hydroperoxide formation.
Recognized by U.S. FDA as GRAS for flavoring use; dermal LD50 in rats >3000 mg/kg indicating low acute toxicity.
- · Established contact allergen in humans per SCCS/1459/11 Table 13-1: classified ++ (10-100 published positive patch test cases). Asterisked as 1999 SCCNFP-identified fragrance allergen.
- · Cross-reactivity with cinnamaldehyde and other cinnamate-derived fragrance allergens documented in clinical case reports (Rubio-González 2015, PMID 25109769).
- · Reg (EU) 2023/1545 expanded the Annex III allergen list to ~80 substances; Entry 87 thresholds for Hexyl Cinnamal remain unchanged in the expansion.
Mandatory EU label disclosure (Annex III Entry 87) when concentration exceeds 0,001% leave-on or 0,01% rinse-off; ingredient cannot be hidden under generic 'Parfum/Fragrance' declaration above these thresholds.
Constituent of Fragrance Mix II (FM II) clinical patch test screen at 5% in petrolatum (since Frosch 2005, PMID 15859994); AHCA reactivity ranks among the five FM II constituents but with lower prevalence than HICC, citral, farnesol, and citronellol.
No standalone CIR safety assessment exists — verified absent from CIR QRT December 2017/July 2018 revision via alphabetical traversal (Hexyl Isostearate present, Hexyl Cinnamal absent). CIR defers fragrance-only ingredients to RIFM Expert Panel and IFRA Standards (IFRA Standard 49, Amendment 2020).
SCCS/1459/11 — Opinion on Fragrance Allergens in Cosmetic Products (adopted 13-14 December 2011, revised 26-27 June 2012). HEXYL CINNAMAL…
“HEXYL CINNAMAL* 101-86-0 ++”— sccs_o_073.pdf, p. 104 (Table 13-1: Established contact allergens in humans)
EU Regulation 1223/2009 Annex III (Restricted Substances) — Entry 87: Hexyl Cinnamal / 2-Benzylideneoctanal, CAS 101-86-0, EC 202-983-3; …
“0,001 % in leave-on products”— EU Reg 1223/2009 Annex III, Entry 87