The difference between folic acid and methylfolate
| Folic acid | Methylfolate (5-MTHF) | |
|---|---|---|
| What it is | A man-made form of vitamin B9 | The active form of folate, also made in supplements |
| Where you find it | Most multivitamins and prenatals; enriched bread, pasta, cereal and corn masa flour | Some supplements and prenatals |
| Stability | Stable; survives cooking and baking, which is why it's used to fortify food | Sold as a supplement; not the form the CDC describes for fortification |
| Neural tube defect evidence | Proven to lower risk | No studies show it lowers risk |
| With an MTHFR variant | Still processed and raises blood folate | Some clinicians prefer it because the body may use it more easily |
"Folate" is the umbrella term for every form of vitamin B9, including natural folate in leafy greens, beans and citrus, folic acid and 5-MTHF.
Folic acid vs methylfolate with an MTHFR variant
The MTHFR enzyme makes 5-MTHF, so it is easy to assume a variant means folic acid doesn't work. The CDC says otherwise: people with an MTHFR variant can process all types of folate, including folic acid. People with two copies of C677T have blood folate only about 16% lower than people with none at the same intake, and 400 mcg of folic acid a day raises blood folate across genotypes.
MedlinePlus notes that a clinician may recommend methylfolate for someone with a variant because it may be easier to use. That is a reasonable choice, not a requirement, and there are no clinical guidelines to change folate intake based on genotype. See MTHFR mutation and MTHFR diet.
Pregnancy: follow your clinician
- The CDC advises 400 mcg of folic acid every day for anyone who could become pregnant, starting at least one month before conception, because neural tube defects form in the first weeks, often before a pregnancy is known.
- This applies even with an MTHFR variant.
- After a past pregnancy affected by a neural tube defect, the CDC cites 4,000 mcg a day starting a month before trying and through the first three months. Your clinician sets this.
- Check your prenatal label: some use 5-MTHF instead of folic acid. The CDC suggests confirming yours contains folic acid.
Don't switch prenatal vitamins or change your folate dose during pregnancy or while trying to conceive without talking to your obstetric clinician or midwife.
Safety and how much is too much
The adult upper limit for folic acid from supplements and fortified foods is 1,000 mcg a day, unless a clinician advises more. High intakes can hide a vitamin B12 deficiency while nerve damage progresses. If you take a folate supplement in any form, it's worth knowing your B12 level; see the vitamin B12 blood test.
Common questions
Is methylfolate better than folic acid?
Not for everyone. Folic acid has the strongest evidence, especially for pregnancy. Methylfolate is a reasonable option some clinicians prefer for people with MTHFR variants.
Should I take methylfolate instead of folic acid if I have MTHFR?
The CDC says people with MTHFR variants can process folic acid. Some clinicians suggest methylfolate anyway; ask yours, and if you could become pregnant, make sure you get 400 mcg of folic acid a day.
Can I take methylfolate while pregnant?
Ask your prenatal clinician. The CDC notes no studies show other folate forms lower neural tube defect risk, so it advises a supplement with folic acid.
Is L-methylfolate the same as 5-MTHF?
Yes, they are names for the same active form of folate, 5-methyltetrahydrofolate.
Can you take too much folic acid?
Adults should stay under 1,000 mcg a day from supplements and fortified foods unless a clinician advises more, because high intakes can mask low B12.
Sources
- About Folic Acid Centers for Disease Control and Prevention
- Clinical Overview of Folic Acid Centers for Disease Control and Prevention
- MTHFR Gene Variant and Folic Acid Facts Centers for Disease Control and Prevention
- MTHFR Gene Test MedlinePlus, U.S. National Library of Medicine
- Folic acid in diet MedlinePlus, U.S. National Library of Medicine
- Folate (Folic Acid): Vitamin B9 The Nutrition Source, Harvard T.H. Chan School of Public Health
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.