Methyl Folate, or (6S)-5-MTHF, is a powerful form of folate, and Quatrefolic® is its fourth-generation delivery system. Our bodies often lack the ability to effectively convert synthetic folic acid into active folate, meaning unmetabolized folic acid can accumulate and disrupt the metabolism of natural folates. Supplementing with 5-MTHF is far better, as it can even cross the blood-brain barrier without masking pernicious anemia!