L-methylfolate (such as Metafolin® and Arcofolin™) is the active form of folate which is directly bioavailable and naturally occurring in foods. In contrast, folic acid, which is part of other conventional dietary supplements, must be activated before use by the body. The efficacy of this metabolic process differs from person to person, meaning that folic acid may not be adequately converted into metabolically active folate by some individuals.
L-methylfolate is identical to the main circulating form of folate in the body. It can be directly used by the body, independent of the underlying genotype of specific folate dependent enzymes. Individuals with polymorphisms in the enzymes involved, such as MTHFR, may not benefit sufficiently from folic acid supplements.