Quick answer

Folate is a B vitamin your body uses to make DNA and new cells, including red blood cells. Adults need 400 mcg DFE a day, and most people in the US get enough from food and fortified grains. Folic acid, the supplement form, has an adult upper limit of 1,000 mcg a day.^1,2

Key facts

Folic acid taken with food is about 85% absorbed, against about 50% of the folate naturally in food.²
That gap is why labels count folate in DFE: 400 mcg of folic acid is listed as 680 mcg DFE.²
Most people in the US get enough, but 17% of women aged 19 to 30 fall short even counting supplements.²
Anyone who could become pregnant is advised to take 400 mcg of folic acid a day, on top of the folate in food.^1,3
The upper limit exists because large amounts of folic acid can hide low vitamin B12.²

What folate does in the body

Your body needs folate to make DNA and other genetic material, and for cells to divide.¹

Folate works as a carrier of single carbon units, the small chemical pieces cells hand along when they copy DNA and RNA and process amino acids. One of its main jobs turns homocysteine, an amino acid in the blood, into methionine, which the body then uses to make a methyl donor needed in many reactions.²

Cells that divide quickly depend most on a steady supply, which is part of why needs go up in pregnancy.²

The body holds about 15 to 30 mg of folate, about half of it in the liver and the rest in blood and other tissues.²

Bacteria in the colon also make folate, but how much this adds to the body's supply is unclear.²

What the evidence shows

Each statement below is a well-established nutrient function, graded moderate, with the amount it rests on beside it. They describe what folate does when you get enough, not an extra effect from taking more.

Has a role in making DNA and in normal cell division*^1,2,4

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*^2,4,5

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

Contributes to normal homocysteine metabolism*^2,4

Moderate evidence

Folate is needed to turn homocysteine, an amino acid in the blood, into methionine. In trials summarized by NIH, folic acid lowered blood homocysteine: by 26% in 818 Dutch adults aged 50 to 70 who took 800 mcg a day for 3 years, and by 18.5% in women who took folic acid with vitamins B6 and B12. The EU permits this statement. Homocysteine is a blood marker, and lowering it has not changed most of the long-term health outcomes it was studied for.

Amount studied: 800 mcg of folic acid a day on its own, and up to 2,500 mcg a day combined with vitamins B6 and B12

Contributes to maternal tissue growth during pregnancy*^1,2,3,4

Moderate evidence

Pregnancy raises the need for folate because of its role in making DNA while tissues grow quickly, so the recommended amount rises from 400 to 600 mcg DFE a day. The EU permits this statement. Separately, US advice is that everyone who could become pregnant gets 400 mcg of folic acid a day from supplements, fortified foods or both, on top of food folate, and the US Preventive Services Task Force recommends a daily supplement with 400 to 800 mcg.

Amount studied: 600 mcg DFE a day in pregnancy from all sources; 400 to 800 mcg of folic acid a day as a supplement for anyone who could become pregnant

How much folate you need

Adults need 400 mcg DFE of folate a day from all sources, the same amount for men and women.¹

The recommended amount rises to 600 mcg DFE a day during pregnancy and 500 mcg DFE while breastfeeding.¹

The recommended amount counts folate from every source, in DFE. The upper limit counts only folate from supplements and fortified foods, in plain micrograms, because folate that occurs naturally in food has not been reported to cause harm.²

Folate, folic acid and methylfolate

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.²

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.²

Supplement labels give folate in mcg DFE and, when folic acid is used, the folic acid amount in parentheses. A label reading 680 mcg DFE (400 mcg folic acid) holds 400 mcg of folic acid.²

Where folate comes from

Folate is naturally present in beef liver, vegetables (especially asparagus, brussels sprouts and dark green leafy vegetables such as spinach and mustard greens), fruits and fruit juices (especially oranges and orange juice), and nuts, beans and peas such as peanuts, black-eyed peas and kidney beans.¹

In the US, folic acid is added to enriched bread, flour, cornmeal, pasta and rice, to fortified breakfast cereals, and to some corn masa flour used for tortillas and tamales.¹

Spinach, liver, asparagus and brussels sprouts are among the richest foods. Because enriched grains have carried folic acid since 1998, bread, pasta and rice count toward the total too.²

Folate for hair, skin and men

NIH lists sores on the tongue and inside the mouth, and changes in the color of the skin, hair or fingernails, among the effects of getting too little folate.¹

Those are signs of a shortage. None of the sources we use report a trial of folate supplements for hair or skin in people who already get enough.

Men need the same 400 mcg DFE a day as women who are not pregnant. US men average 602 mcg DFE a day from food alone, and about 5% of men over 50 take in more folic acid than the upper limit, mostly from supplements.^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 lists 680 mcg DFE, which is 400 mcg of folic acid. That is more than the 400 mcg DFE adults need each day and 40% of the 1,000 mcg upper limit for folic acid. It is made for men and is not meant for pregnancy.^1,2

Side effects, medicines and who should ask first

The upper limit for adults is 1,000 mcg a day of folate from supplements and fortified foods, which for folic acid equals about 1,667 mcg DFE. It is 800 mcg for teens aged 14 to 18. Folate naturally present in food has no limit, and the limits do not apply to higher doses taken under medical supervision.^1,2

Large amounts of folic acid can correct the anemia caused by low vitamin B12 without stopping the nerve damage it also causes, so the B12 problem can go unnoticed until the damage is permanent. Large doses might also make the effects of low B12 worse.^1,2,5

Ask your pharmacist or doctor first

Folate supplements could interfere with methotrexate when it is used for cancer, and the methotrexate label says to take products containing folic acid then only if a doctor directs it. When methotrexate is used for rheumatoid arthritis, psoriasis or polyarticular juvenile idiopathic arthritis, the same label tells prescribers to give folic acid or folinic acid to reduce side effects.^1,2,6,7

On the medicine's label

Ask your pharmacist or doctor first

Phenytoin, carbamazepine and valproate can lower blood folate, and folate supplements might lower blood levels of these medicines. The phenytoin and folic acid labels both say folic acid can lower phenytoin levels or weaken its effect.^1,2,5,8

On the medicine's label

Ask your pharmacist or doctor first

Sulfasalazine reduces how much folate the body absorbs and can lead to low folate. Its label reports reduced absorption of folic acid when the two are taken together.^1,2,9

On the medicine's label

Folate deficiency is rare in the US. When it happens, it can cause megaloblastic anemia, with weakness, fatigue, trouble concentrating, irritability, headache, heart palpitations and shortness of breath. Low vitamin B12 can cause the same blood picture, so these signs need a doctor's diagnosis rather than a supplement.^1,2

Ask first if you take methotrexate, an anti-seizure medicine or sulfasalazine
Ask first if you plan to take more than 400 mcg of folic acid a day and have not had your vitamin B12 checked⁵
Ask first if you have had colorectal adenomas or colorectal cancer¹
Ask first if you are pregnant, planning a pregnancy or breastfeeding, or have had a pregnancy affected by a neural tube defect²

Questions people ask

What is the difference between folate and folic acid?

Folate is the name for the whole vitamin, including the forms found in food. Folic acid is the man-made form used in fortified foods and most supplements, and it is absorbed better than food folate.²

Is it better to get folate from food or from a supplement?

Most people in the US get enough from food and fortified grains. A supplement matters most when needs are higher, as for anyone who could become pregnant, who is advised to take 400 mcg of folic acid a day on top of food.^1,2

Is it safe to take folic acid every day?

At or under the adult upper limit of 1,000 mcg a day from supplements and fortified foods, daily folic acid is the standard advice for anyone who could become pregnant. Take more only on medical advice, partly because large amounts can hide low vitamin B12.¹

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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.