Abstract:In view of the poor stability and low bioavailability of folic acid （FA） and its derivatives，such as 6S-5-methyltetrahydrofolate （6S-5-MTHF），this study systematically reviewed their relevant metabolic pathways.Emphasis was placed on elucidating the mechanisms by which key environmental factors，including light，temperature，pH，and oxygen，affect their stability.On this basis，the feasibility of strategies to enhance stability，such as optimizing encapsulation techniques，incorporating appropriate stabilizers，and controlling external environmental conditions，was explored.This review aimed to provide a theoretical reference and practical basis for the effective application of FA compounds in the food industry and pharmaceutical formulations.