Glycerin vs Pentylene Glycol: which is worse?

What is Glycerin?

Glycerin is a simple polyol (sugar alcohol) that is colorless, odorless, and viscous. It naturally occurs in all animal and vegetable fats and is the backbone of triglyceride molecules. Cosmetic glycerin is typically derived from vegetable oils (plant-based) or as a biodiesel byproduct.

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.

Documented risks

Glycerin: Glycerin is one of the safest cosmetic ingredients known, with centuries of use. The CIR has repeatedly confirmed its safety. It is non-irritating, non-allergenic, and non-toxic. At very high concentrations in leave-on products (>30%), it can have a dehydrating paradox effect — pulling water from the dermis if the environment is very dry — but this is not a health risk. It is safe for all ages including infants.

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.