Should I take methylfolate or folic acid?

Folate is essential for making DNA and for methylation. Supplements come in two main forms, and the choice between them confuses a lot of people.

The key difference

• Folic acid is the synthetic form used in fortified flour, cereals and most multivitamins. The body converts it through several steps — including the MTHFR enzyme — into the active form.
• Methylfolate (L-methylfolate or 5-MTHF) is the active form. It bypasses the conversion steps.

According to the NIH Office of Dietary Supplements, the Recommended Dietary Allowance for adults is 400 mcg dietary folate equivalents per day. The upper limit for synthetic folate from supplements and fortified foods is 1,000 mcg a day, partly because high intakes can mask vitamin B12 deficiency.

What guidelines say

The US Preventive Services Task Force recommends that everyone who is planning or capable of pregnancy take a daily supplement with 0.4 to 0.8 mg (400–800 mcg) of folic acid. The USPSTF specifically notes that people with MTHFR variants can still process folic acid, and doesn't recommend a different form based on genotype. Folic acid has the decades of trial data behind neural tube defect reduction.

When methylfolate may be considered

Some people with two copies of the MTHFR C677T variant, or who don't tolerate folic acid, choose methylfolate. It's a reasonable option, but it isn't required, and genotype alone isn't a reason to take high doses. See what MTHFR means on a genetic test.

The bottom line

A folate-rich diet plus folic acid covers most people's needs. Methylfolate is a fine alternative, not a necessity. Compare the two in detail on our methylfolate vs folic acid page, and talk with a clinician before changing doses, especially if you're pregnant or planning pregnancy.