What it is
Glycol refers to ethylene glycol, a simple two-carbon diol that is fully miscible with water. In cosmetic formulations it can serve as a humectant and as a carrier solvent for other ingredients. The term glycol is sometimes used loosely on labels, but as an INCI entry it denotes ethylene glycol specifically.
Safety & warnings
Ethylene glycol is hazardous if ingested, so it is not used in products intended to be swallowed. In topical cosmetic use it appears at low levels; formulators more commonly choose related glycols such as propylene glycol or butylene glycol for skin care.
Origin & sourcing
Synthetic. Ethylene glycol is produced industrially, typically by hydration of ethylene oxide.
Questions everyone asks
What does glycol do in a sunscreen?
It mainly acts as a humectant to help retain moisture and as a solvent to dissolve and carry other ingredients in the formula.
Is glycol the same as propylene glycol?
No. As an INCI term, glycol refers to ethylene glycol, which is a different molecule from propylene glycol, though both are diols used as solvents and humectants.