5-MTHF folate is the most abundant folate found in the human body. It is found naturally in food, but is most easily absorbed from a dietary supplement. MTHF folate is the most bioavailable folate found in food supplements. It can be used immediately by your body and does not need to be converted by the enzyme methylenetetrahydrofolate reductase (MTHFR).
Up to 25% of the population has a variant in the MTHFR gene (MTHFR 677TT) that significantly impairs their ability to metabolise folic acid. The research is still preliminary, but people with the MTHFR 677TT variant are likely to benefit from MTHF folate supplementation rather than taking a folic acid supplement.