Butylene Glycol

Butylene glycol (1,3-butanediol) is one of the most common cosmetic glycols — humectant, solvent for extracts, and texture aid[1].

What it does

Holds water, helps wet botanical extracts, and can reduce viscosity of gels. Often sits beside glycerinGlycerinStrongGlycerin · Polyol humectantThe workhorse humectant: cheap, endlessly studied, and better than the fashionable alternatives at holding water.Open in the Index → and propanediolFunctionalPropanediolFunctionalPropanediol · Glycol humectant / solventBio-based 1,3-propanediol humectant and solvent; lighter feel than butylene glycol for many formulas.Open in the Index →.

The evidence

CIR assessed butylene glycol as safe as used in cosmetics[1]. Functional humectancy is well accepted; it is not a therapeutic active.

How to use it

Ignore for routine building — it is scaffolding. Relevant mainly for rare contact allergy cases.