Methylfolate side effects

Folate Supplements for MTHFR Mutations

In years past, those with MTHFR mutations and either a history of miscarriage or neural tube defects were advised to take 4000 micrograms of synthetic folic acid to get around impaired folate metabolism.  It is now clear that a better approach is to supplement directly with methylfolate. Those with MTHFR mutations typically need at least 800 mcg per day of methylfolate.

Troubleshooting Methylfolate Supplements & Side Effects

The only problem with supplementing directly with methylfolate is that it can sometimes cause side effects such as mood changes and joint pain, particularly when taken in higher doses and if vitamin B12 is low.

If you are taking a prenatal that contains 800 mcg or more of methylfolate and find that it bothers you,  consider switching to a multivitamin that contains 400 micrograms of methylfolate (such as Thorne Basic Nutrients 2/day), and then add 400 to 1200 micrograms of folinic acid and perhaps some additional vitamin b12.

Folinic acid is another form of folate that is naturally found in foods. It is more readily converted to methylfolate than synthetic folic acid. I recommend Seeking Healthy Folinic Acid Lozenges, which come in two versions: one with hydroxo B12 and one that is folinic acid alone.  Another good quality product is Kirkman Labs Folinic Acid

Most people , however, will not have any problems with a prenatal containing 800-1000mcg of methylfolate.  Good options include: Thorne Basic Prenatal and Mama Bird. (For those the UK, I recommend Naturelo Prenatal).  These products all have very positive reviews on Amazon, without reports of side effects that can occur with high doses of methylfolate.


There are of course many other strategies to further improve fertility and reduce the risk of miscarriage for those with MTHFR mutations, as I explain in It Starts with the Egg.