What it is
1,2-Hexanediol is a clear, colorless, mildly viscous aliphatic diol with two hydroxyl groups on adjacent carbons of a six-carbon chain. In formulations it serves several roles at once: it acts as a humectant that helps leave-on products hold water, as a solvent that improves the solubility and clarity of other ingredients, and as a skin-conditioning agent that lends a soft feel. It is also widely used as a preservative booster, supporting a formula's antimicrobial system so it is often paired with a primary preservative rather than relied on alone.
Safety & warnings
Cosmetic reference sources describe 1,2-hexanediol primarily in terms of its functional benefits as a humectant, solvent, and preservative-support ingredient, and it appears in a wide range of mainstream leave-on and rinse-off products. Published ingredient pages reviewed here did not detail specific irritation or allergen concerns. As with any multifunctional glycol-type ingredient, people with very reactive or compromised skin may prefer to patch test a new product before regular use.
Origin & sourcing
1,2-Hexanediol is produced synthetically as a multifunctional aliphatic diol for specialty chemical and personal-care use; it is not sourced from a natural extract. It is supplied as a clear, colorless, hygroscopic liquid with a faint characteristic odor.
Questions everyone asks
Is 1,2-hexanediol a preservative?
It is not classified as a traditional preservative, but it works as a preservative booster, supporting a formula's antimicrobial system and helping extend shelf life when used alongside a primary preservative.
Does 1,2-hexanediol moisturize skin?
It provides moderate humectant properties that help leave-on products such as creams and serums retain water, though it is meant to support rather than replace primary moisturizers.
Is 1,2-hexanediol natural or synthetic?
It is a synthetic diol manufactured for use in cosmetics and other consumer products, supplied as a clear, colorless liquid.