What is Folic acid? Folic acid or folate is a B vitamin. It is also referred to as vitamin M, vitamin B9, vitamin Bc (or folacin), pteroyl-L-glutamic acid, and pteroyl-L-glutamate. Food supplement manufacturers often use the term folate for something different than “pure” folic acid: in chemistry, folate refers to the deprotonated ion, and folic acid to the neutral molecule—which …