1,2-Propanediol (propylene glycol) ek chhota diol hai jo skincare mein humectant, solvent aur penetration enhancer ke taur par use hota hai. Yeh actives ko dissolve karne aur moisture ko retain karne mein madad karta hai. Yeh zyada tar formulations mein base ingredient ke roop mein use hota hai, treatment ingredient nahin.