How Much Folic Acid Should I Take? Daily Dosage by Age and Situation

Most healthy adults need 400 mcg DFE of folate a day from all sources, and a balanced diet with fortified foods can often meet that.¹ If you could become pregnant, the recommendation is more specific: 400 mcg of folic acid every day from a supplement, fortified foods, or both, on top of the folate in your food.² For adults, do not go above 1,000 mcg of folic acid a day from supplements and fortified foods unless a clinician directs it.¹

This page sets out the official numbers by age and life stage, explains the difference between mcg folic acid and mcg DFE, and separates everyday nutrition from pregnancy prevention and medical treatment.

Quick answer: folic acid dose by situation

These are different recommendations for different purposes. Do not combine them into one number.

How much folate do you need by age?

The Recommended Dietary Allowance (RDA) is the daily amount that meets the needs of most healthy people. For folate it is given in mcg DFE.¹

The Daily Value used on U.S. nutrition labels is 400 mcg DFE for adults and children aged four and older. A product with 20% or more of the Daily Value per serving counts as a high source.¹

mcg folic acid vs mcg DFE: the unit that trips everyone up

Dietary Folate Equivalents (DFE) account for the fact that folic acid is absorbed better than folate found naturally in food.¹ At least 85% of folic acid taken with food is bioavailable, compared with about 50% of natural food folate.¹

So 400 mcg of folic acid taken with food equals about 667 mcg DFE. A label showing "667 mcg DFE (400 mcg folic acid)" is describing one dose two ways.¹ U.S. labels list total folate in mcg DFE and, when folic acid is added, show the folic acid amount in parentheses.¹

Common adult supplements contain 400 to 800 mcg of folic acid, often shown as 680 to 1,360 mcg DFE.¹ You can convert your own numbers with our folate DFE calculator, and our guide to folate vs folic acid explains the forms in more depth.

If you could become pregnant

CDC recommends 400 mcg of folic acid every day for everyone capable of becoming pregnant, from supplements, fortified foods, or both, in addition to a varied diet.⁷² USPSTF gives an A grade to a daily supplement of 400 to 800 mcg, starting at least one month before conception and continuing through the first two to three months of pregnancy.³

People who have had a pregnancy affected by a neural tube defect (NTD) are in a separate group: CDC recommends 4,000 mcg (4 mg) daily, starting one month before conception, coordinated with a clinician.⁴² Other risk factors, such as certain antiseizure medicines, diabetes present before pregnancy, or malabsorption after bariatric surgery, also call for preconception counseling.⁸³

Food alone is not a reliable substitute for the specific 400 mcg folic acid recommendation if pregnancy is possible.⁷ Folic acid is also the only form of folate shown in studies to help prevent NTDs.⁴ Full details are in how much folic acid for pregnancy.

How much is too much?

The tolerable upper intake level (UL) applies to folic acid from supplements and fortified foods. It does not include folate that occurs naturally in food.¹

The adult UL is 1,000 mcg of folic acid, not 1,000 mcg DFE. A supplement labeled "1,667 mcg DFE (1,000 mcg folic acid)" is already at the adult UL before you count fortified foods.¹ A 1 mg tablet is the same as 1,000 mcg.¹

The UL is not a toxicity threshold, and it does not apply when a clinician prescribes a higher dose for a specific reason.¹ Still, taking more than recommended is not known to give better NTD protection for average-risk people, and high doses should have a defined reason, duration, and clinician overseeing them.⁹¹⁰ See how much folic acid is too much for the details on B12, unmetabolized folic acid, and other concerns.

Treatment doses are a different category

Prevention doses and treatment doses should not sit in the same mental box.⁶⁵¹¹

• Folate-deficiency anemia: folic acid treats it, but the dose and duration depend on the diagnosis, and the cause must be corrected too. Unexplained anemia should not be self-treated until vitamin B12 deficiency has been checked.⁶¹²
• Low-dose methotrexate: a common U.K. regimen is 5 mg folic acid once weekly on a different day from methotrexate, but regimens vary, so follow the exact prescription.⁵
• High-dose methotrexate (oncology): uses leucovorin (folinic acid), not folic acid, on schedules set by the care team.¹¹¹³

Does MTHFR change how much you need?

Generally, no. People with common MTHFR variants can process all forms of folate and should not avoid folic acid on that basis.⁹ CDC still recommends 400 mcg a day of folic acid for people with common variants who could become pregnant, and more is not automatically better.⁹

Rare MTHFR disorders are different from common variants found on consumer gene tests and need specialist evaluation.⁹

Safety at recommended amounts

At recommended amounts, folic acid has a strong safety record. CDC states that 400 mcg a day has not been shown to cause harm, and USPSTF found usual-dose supplementation is not associated with serious harms.¹⁰³ Minor effects such as nausea, reduced appetite, gas, or bloating can happen, though most people tolerate it well.¹⁴ Read more about folic acid side effects.

This article is for general education and is not medical advice. Doses and needs differ from person to person, so talk with your clinician or pharmacist about your situation. Read our editorial policy and medical disclaimer.