Pentylene Glycol vs Propylene Glycol (Cosmetic): which is worse?

What is Pentylene Glycol?

Pentylene glycol (1,2-pentanediol) is a multifunctional cosmetic ingredient used as a humectant, solvent, and antimicrobial/preservative booster. It is increasingly used as a 'natural' alternative to traditional glycols and can be derived from sugarcane.

What is Propylene Glycol (Cosmetic)?

Propylene glycol is a small synthetic organic compound (diol) used in cosmetics as a humectant, solvent, and skin-conditioning agent. It is produced from propylene oxide (petroleum) but also from bio-based sources.

Documented risks

Pentylene Glycol: Pentylene glycol has a good safety and tolerability profile. It is less irritating than propylene glycol and is suitable for sensitive skin formulations. No carcinogenic or endocrine effects are identified. It is COSMOS/ECOCERT acceptable when bio-based. Minor irritation is possible at high concentrations in compromised skin.

Propylene Glycol (Cosmetic): Propylene glycol is safe at typical cosmetic use concentrations (1–15%). The CIR and EU SCCS have both reviewed and affirmed its safety. It can cause contact sensitization and irritant reactions in some individuals, particularly at concentrations above 5% in leave-on products; those with sensitive or compromised skin may react. It is rapidly metabolized if absorbed and is not bioaccumulative. There is no evidence of carcinogenicity or endocrine disruption at cosmetic use levels. Note: this entry covers topical cosmetic use; ingested large doses (antifreeze context) are toxic, which is a separate matter.