Butylene Glycol

Often included in a skin care formula to enhance the texture and penetration

Known to be hygroscopic, meaning it can increase skin’s water content (aka hydration)

May also help boost a formula’s stability

Clear, viscous liquid

Also known as butane-1,3-diol

Butylene glycol is a commonly used ingredient that plays multiple roles in cosmetics, including as a humectant, texture enhancer, solvent, and penetration booster. Research indicates butylene glycol not only helps raise water content in skin (aka hydration) but may also contribute to decreasing roughness on the surface of skin (depending on how it’s combined in the formula). While not known as a preservative in and of itself, some of butylene glycol’s properties can help boost a formula’s stability against microorganisms that may harm skin’s surface.

As a raw material, butlyene glycol is a clear and viscous liquid. It is similar to propylene glycol but has a lighter texture. It is used in a wide range of concentrations, with reports of up to 50%, although many suppliers cap it at 30%. The minimum amount tends to hover around 0.5%, in which case it’s typically part of a blend with plant extracts and/or preservatives.

The Cosmetic Ingredient Review board has evaluated several toxicology tests and other research concerning butylene glycol over the years and has determined it is safe within the wide concentration range currently used in cosmetics products. The U.S. Food and Drug Administration (FDA) has even determined that butylene glycol is safe as a food additive.

See: Propylene Glycol