Isohexadecane
Also known as Isohexadecane, Branched C16 hydrocarbon, 2,2,4,4,6,6,8,8-octamethylnonane
“CIR Expert Panel says: safe as used in cosmetics.”
Isohexadecane is a branched-chain synthetic C16 hydrocarbon (isoalkane) widely used as a lightweight emollient and solvent in cosmetics. The CIR Expert Panel assessed it as safe when formulated to be non-irritating (IJT 31(S3): 269-295, 2012), consistent with the class-wide assessment covering related isoalkanes (isododecane, isoeicosane). A 2004 case report (Bharati and King, Contact Dermatitis) documents a confirmed case of allergic contact dermatitis from isohexadecane via patch testing, indicating rare sensitisation potential. Emollient spreading studies (Gore et al. 2020) characterise its in-use behaviour in O/W emulsions but do not raise safety concerns.
Lightweight, non-greasy emollient providing skin smoothness and spreadability
Solvent for actives and lipophilic ingredients in cosmetic formulations
CIR Expert Panel found safe when formulated to be non-irritating: 269-295, 2012)
Good oxidative stability as a saturated hydrocarbon; no rancidity concerns
- · Rare allergic contact dermatitis documented by patch-test-confirmed case report (Bharati and King 2004, PMID 15186389)
- · CIR approval is qualified: formulations must be non-irritating (SQ finding)
CIR Quick Reference Table (12/2017, revised 07/2018) — Isohexadecane row: Finding=SQ, Detail=safe when formulated to be non-irritating, C…
“Isohexadecane | SQ | safe when formulated to be non- irritating | IJT 31(S3): 269-295 (2012)”— QRT-122017revised072018.pdf, p. 64