Citral
Also known as Citral, 3,7-Dimethyl-2,6-octadienal, Geranial/Neral mixture, Lemonal
“EU SCCS says: restricted.”
Citral (CAS 5392-40-5) is a well-characterized fragrance allergen — a mixture of two acyclic monoterpenoid isomers, geranial (E) and neral (Z), responsible for lemon/citrus odor in essential oils (lemongrass, lemon, lime, citronella). It is regulated as a fragrance allergen under EU Cosmetics Regulation 1223/2009 Annex III (Reference 70), requiring label declaration above 0.001% in leave-on products and 0.01% in rinse-off products. The 2024 SCCS Final Opinion (SCCS/1666/24) reviewed industry-derived QRA2 safety levels for the sensitisation endpoint and concluded that QRA2-derived concentrations can be considered safe in relation to induction of sensitisation, while flagging methodological refinements still needed before a firm conclusion could be drawn; SCCS agreed a NESIL (No Expected Sensitisation Induction Level) of 1400 µg/cm² for Citral. The RIFM Fragrance Ingredient Safety Assessment (Api et al. 2020, FCT) and earlier dermal sensitization threshold review (Lalko & Api 2008) provide the underlying toxicology dataset. Citral is NOT listed in the CIR Quick Reference Table (verified absent in QRT versions Dec 2017/Jul 2018, Sept 2022, and Dec 2025) — fragrance materials are typically assessed by RIFM/IFRA/SCCS rather than CIR. Beyond sensitisation, animal eye-toxicity studies have reported lens opacity / cataract effects at high doses (mechanism: Citral inhibits ALDH1A1 retinoic-acid metabolism in lens tissue), but this is not a routine cosmetic-use concern at fragrance-level concentrations.
Major fragrance ingredient providing lemon/citrus aroma; principal odor component of lemongrass, lemon, lime, citronella, and many citrus essential oils
Authoritative SCCS sensitisation review (2024) plus comprehensive RIFM safety assessment (2020) and dermal-sensitisation threshold derivation (Lalko & Api 2008) provide a data-rich exposure-and-toxicology dataset
QRA2-based safe use levels established by industry methodology and accepted by SCCS as safe for sensitisation induction at proposed cosmetic concentrations (with methodology caveats)
- · No CIR safety assessment exists (Citral absent from CIR QRT Dec 2017/Jul 2018, Sept 2022, and Dec 2025 versions) — toxicology coverage relies on SCCS and RIFM rather than CIR
Regulated EU fragrance allergen (Annex III Reference 70): label declaration required above 0.001% (leave-on) or 0.01% (rinse-off); Citral is on the original list of 26 fragrance allergens with documented sensitisation potential in clinical patch-test studies
Pre-oxidized Citral is more sensitising than fresh material — air-oxidation of geranial/neral generates secondary reactive products; storage and product-stability matter for real-world allergen exposure
SCCS/1666/24 (29 July 2024) considered Citral safe at QRA2-derived levels for sensitisation endpoint induction, but flagged methodological aspects of QRA2 needing refinement; final conclusion provisional pending those clarifications
Citral inhibits ALDH1A1 (aldehyde dehydrogenase 1A1) and has been associated with lens opacity / cataract formation in high-dose animal eye studies; not a typical concern at fragrance use levels but a documented mechanistic finding
SCCS/1666/24 Final Opinion on Citral (CAS No. 5392-40-5, EC No. 226-394-6) - sensitisation endpoint, adopted 29 July 2024 — QRA2-derived …
“The SCCS has noted that the QRA2 methodology has indicated that Citral can be considered safe in relation to the induction of sensitisation at the concentrations proposed for use in cosmetic products. However, the SCCS has identified some aspects of the QRA2 methodology that still need clarification and therefore, some refinement is needed before a firm conclusion on the safety of Citral could be drawn.”— sccs_o_287.pdf, Section 4 CONCLUSION (p. 44); also Section 1 ABSTRACT (p. 3)
EU Regulation 1223/2009 Annex III (Restricted Substances) — Reference 70: 3,7-Dimethyl-2,6-octadienal (INCI: Citral, CAS 5392-40-5); frag…
“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 0,01 % in rinse-off products”— EU Reg 1223/2009 Annex III, Reference 70 (Citral / 3,7-Dimethyl-2,6-octadienal), column (h)