Propylene Glycol (Cosmetic) vs Sodium Hyaluronate: which is worse?

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.

What is Sodium Hyaluronate?

Sodium hyaluronate is the sodium salt form of hyaluronic acid. It has a slightly smaller molecular weight than free hyaluronic acid, which allows better penetration into the outer layers of the stratum corneum. It is the form most commonly used in topical serum formulations.

Documented risks

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.

Sodium Hyaluronate: Sodium hyaluronate shares the excellent safety profile of hyaluronic acid. It is an endogenous compound, non-allergenic, non-irritating, and thoroughly reviewed as safe by the CIR. No concerns regarding carcinogenicity, hormones, or systemic toxicity exist.