Folinic acid (5-formyltetrahydrofolate) is a naturally occurring folate. It can convert easily to methylfolate without the enzyme dihydrofolate reductase. This allows your body to regulate the amount of methylated vitamins it needs, without flooding your body and therefore avoiding negative effects.
It is not folic acid
It is important to note that folinic acid is different from folic acid. Folic acid is a synthetic, oxidized, and water-soluble form of folate (vitamin B9) that does not exist in nature, whereas folinic acid exists naturally and is biologically active.
Methylfolate + Folinic Acid
Methylfolate is needed to bypass the MTHFR mutation and support methylation. Folinic acid is needed to support DNA base production, DNA repair, energy production, and neurotransmitter formation. During growth periods when a lot of DNA is being made, such as in pregnancy, it is very important to have both.