L-5MTHF is the active form of folate, but ironically, it is far less studied than the synthetic (inactive) form folic acid. Because of that, the safe upper limit of L-5MTHF is not known precisely, but we can draw some conclusions from existing data about the risks of high-dose folic acid.

Methylation is a very small, foundational chemical function in your body. It involves the moving of a methyl group, which is a carbon with three hydrogens that you can picture a lot like a Mickey Mouse head with an extra ear (shudder).