Butylene Glycol vs Urea (Cosmetic): which is worse?

What is Butylene Glycol?

Butylene glycol (1,3-butanediol) is a small diol used in cosmetics as a humectant, solvent, and skin-conditioning agent. It is closely related to propylene glycol but has a slightly larger molecular structure, often making it even better tolerated.

What is Urea (Cosmetic)?

Urea is a naturally occurring organic compound that is a byproduct of protein metabolism, found in urine and skin. In cosmetics, synthetic urea is used at varying concentrations for different effects: 2–10% as a humectant; 10–20% as a keratolytic (softening/exfoliating thickened skin); 20–40% for calluses and nail penetration.

Documented risks

Butylene Glycol: Butylene glycol has a good safety profile and is better tolerated by sensitive skin than propylene glycol at equivalent concentrations. The CIR has confirmed it safe for cosmetic use. It is non-carcinogenic, non-mutagenic, and not an endocrine disruptor. Contact sensitization is rare. It is widely used in Korean beauty (K-beauty) formulations as a preferred humectant.

Urea (Cosmetic): Cosmetic urea is safe and has been used for decades in dermatology for very dry and keratotic skin conditions. The CIR has confirmed safety at cosmetic concentrations. At concentrations above 10%, it may cause mild stinging on broken or inflamed skin. No carcinogenicity or hormone disruption is documented. Urea is considered an active ingredient in OTC skin softeners in Europe.