Folic acid is the synthetic form of folate. Over 50% of the population has MTHFR gene mutations and cannot process folic acid properly which then becomes toxic to the body. That’s because MTHFR mutations have a hard time converting folic acid so the body can use it. It’s all about homocysteine. MTHFR SNPs lack the enzymes to break down the levels in the body. Folate (natural form of B9) is needed to do this. Folic acid (synthetic form of B9) becomes toxic to the body. Symptoms of MTHFR mutations