A method of reducing photodegradation of cholecalciferol when exposed to UV radiation in a composition containing cholecalciferol comprising combining with cholecalciferol a compound of formula (I) in an amount effective to quench excited state energy from cholecalciferol and transfer the excited state energy from cholecalciferol to the compound of formula (I),wherein one of R1 and R2 is a straight or branched chain C1-C30 alkoxy radical, and the non-alkoxy R1 or R2 is hydrogen； and R3 is a straight or branched chain C1-C30 alkyl radical, thereby photostabilizing the cholecalciferol compound.
