Quick answer

Folate is the vitamin's family name and the form in food. Folic acid is the man-made form in fortified foods and most supplements: about 85% is absorbed with food, against about 50% of food folate. Methylfolate is the main form in blood and, as a supplement, absorbs as well or better.¹

Key facts

Labels count folic acid at 1.7 mcg DFE per microgram; for methylfolate, each maker picks a factor no higher than 1.7.¹
Whichever form you take, the folate circulating in your blood ends up mostly as methylfolate.^1,2
US advice for anyone who could become pregnant names folic acid, even for people with an MTHFR variant.³
Folate was formerly called folacin and is sometimes called vitamin B9.¹

The three forms

Folate in food comes in forms with extra glutamate links that the gut trims off before absorbing them. About half of it is absorbed, against at least 85% of folic acid taken with food.¹

Folic acid is the man-made form used in fortified foods and most supplements. An enzyme, dihydrofolate reductase, must convert it before the body can use it, and how active that enzyme is varies widely between people.¹

Methylfolate, also sold as L-methylfolate or 5-MTHF, is the main form of folate in the blood. As a supplement it is absorbed as well as folic acid or better, but no official factor converts it to DFE: the FDA lets makers use the folic acid factor of 1.7 or their own lower one.¹

Folate forms side by side¹
What to compare	Food folate	Folic acid	Methylfolate
Where it is found	Leafy greens, beans, liver, fruit	Fortified grains and most supplements	Some supplements; the main form in blood
Share absorbed	About 50%	About 85% with food, nearly 100% without	As much as folic acid or more
Label conversion	1 mcg counts as 1 mcg DFE	1 mcg counts as 1.7 mcg DFE	Up to 1.7 mcg DFE per mcg, set by the maker

What folic acid does

Once absorbed, folic acid is converted into the same active forms the body makes from food folate, so the functions below apply whichever form you take.¹

Has a role in making DNA and in normal cell division*^1,3,4

Moderate evidence

A long-established role of the vitamin. NIH describes folate as needed to make DNA and other genetic material and for cells to divide, and the EU, after review by its food safety authority, permits the statement that folate has a role in the process of cell division. It describes what folate does at recommended intakes, not an added effect from larger amounts.

Amount studied: Recommended intake: 400 mcg DFE a day for adults, from all sources

Contributes to normal blood formation*^1,4,5

Moderate evidence

Red blood cells are made from rapidly dividing cells, which need folate to copy their DNA. NIH explains that when this step falters, the body makes red blood cells that are unusually large and abnormal, and the folic acid prescribing label describes an outside source of folate as required to keep red blood cell production normal. The EU permits the statement that folate contributes to normal blood formation.

Amount studied: Recommended intake: 400 mcg DFE a day for adults, from all sources

Converting folic acid, and unmetabolized folic acid

Single doses of 300 or 400 mcg of folic acid leave some unchanged folic acid in the blood, while doses of 100 or 200 mcg do not. Whether this unmetabolized folic acid affects health is not known.¹

How often you take it may matter too: in research NIH summarizes, frequent small doses left more of it circulating than one larger dose of the same total. Possible effects on immune cells are still being studied.¹

In a crossover study of 24 women, a single dose of methylfolate raised plasma folate sooner and higher than the same amount of folic acid, whether or not they carried two copies of the MTHFR variant, and it rarely left unchanged folic acid in the blood.²

MTHFR and methylfolate

People with two copies of the MTHFR 677C>T variant make methylfolate less efficiently. About 25% of Hispanic people, 10% of White and Asian people and 1% of African American people carry two copies. NIH calls the research on supplements for them inconclusive, while noting that some might do better with methylfolate.¹

In a 24-week trial in 144 women, 416 mcg a day of methylfolate raised red blood cell folate more than 400 mcg a day of folic acid.⁶

This is the case made for methylfolate: it skips the step the variant slows. The CDC, as NIH reports, still advises 400 mcg of folic acid rather than methylfolate for anyone who could become pregnant.^1,2

Which to choose

Folic acid is the form behind US pregnancy advice and grain fortification, and it has a fixed DFE factor. Methylfolate is absorbed at least as well and rarely leaves unchanged folic acid in the blood, but its DFE count varies by maker. Food folate counts toward your needs and has no upper limit.^1,2

What's in ours

What’s in ours

Men's Multi: Folate, 680 mcg DFE (400 mcg Folic Acid) per serving, from the label

Men's Multi uses folic acid: 400 mcg per serving, which its label lists as 680 mcg DFE. That meets the 400 mcg DFE adult recommendation the functions above are based on.¹

Cautions for every form

Choosing methylfolate does not remove the cautions. Large amounts of any folate can mask low vitamin B12 while the nerve damage it causes goes on, and methotrexate, some anti-seizure medicines and sulfasalazine interact with folate whatever its form.^1,3

Methylfolate studied as an add-on to antidepressants was given at 7,500 to 15,000 mcg a day, far above the upper limit, and NIH says doses like these should be taken only under medical supervision.¹

Questions people ask

Is methylfolate better than folic acid?

It is absorbed as well or better, and in one 24-week trial it raised red blood cell folate more. But US advice for anyone who could become pregnant still names folic acid, and methylfolate has no official DFE factor.^1,6

What does folic acid do?

Once converted, the same jobs as folate from food: the body uses it to make DNA, to divide cells and to process homocysteine. It is also the form used to fortify grains in the US.^1,3

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.