Quick answer

NIH's upper limits for folate from supplements and fortified foods rise with age: 300 mcg a day at ages 1 to 3, 400 at 4 to 8, 600 at 9 to 13 and 800 at 14 to 18. None is set for infants. Ask a pediatrician before giving a child a folate supplement.^1,2

Key facts

NIH's upper limits for folate from supplements and fortified foods are 300 mcg at ages 1 to 3, 400 at 4 to 8, 600 at 9 to 13 and 800 at 14 to 18.^1,2
No upper limit is set for infants, because breast milk, formula and food should be their only sources of folate.²
Folate that is naturally present in food has no upper limit.^1,2
Even counting supplements, 19% of girls aged 14 to 18 get less than the average requirement.²
NIH says all teen girls who could become pregnant should get folic acid from supplements, fortified foods or both.¹

What are the upper limits for children and teens?

NIH's upper limits apply to folate from supplements and fortified foods and drinks, not to the folate in ordinary food. They are the clearest official statement on how much is too much for a child, and they rise with age.^1,2

Upper limits for folate from supplements and fortified foods, by age^1,2
Age	Upper limit a day
Birth to 12 months	Not established
1 to 3 years	300 mcg
4 to 8 years	400 mcg
9 to 13 years	600 mcg
14 to 18 years	800 mcg

The limits do not apply to higher amounts taken under medical supervision, and NIH says people should not go above them unless a health care provider recommends it.^1,2

Folate that is naturally present in food and drinks is not harmful, and the upper limit does not apply to it.^1,2

Why do teen girls come up in folate advice?

The recommendation is not about supplements for every child. NIH says all women and teen girls who could become pregnant should get folic acid from supplements, fortified foods or both, because about half of US pregnancies are unplanned. NIH also lists teen girls aged 14 to 18 as one of the groups more likely to have trouble getting enough folate.^1,2

Even counting supplements, 19% of girls aged 14 to 18 and 17% of women aged 19 to 30 get less than the average requirement, as do 23% of non-Hispanic Black women.²

These points concern folic acid for girls and women who could become pregnant. NIH's fact sheets do not make a comparable recommendation for boys or for younger children.¹

What cautions apply to a child or teen taking folic acid?

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.^1,2,3

The label of a folic acid tablet adds that higher doses should not be used unless an anemia caused by vitamin B12 deficiency has been ruled out or is being adequately treated. It lists separate maintenance amounts for infants, for children under 4 and for children 4 and older, which apply to a child under treatment for a deficiency.³

The sources checked do not address methylfolate in children. NIH describes methylfolate as an option for some people with the MTHFR C677T gene variant, without separate guidance for young people.^1,2

What do the sources not say?

None of the sources checked reports safety trials of folic acid supplements in healthy children. NIH says the limits were set from the way folate interacts with vitamin B12, for the synthetic forms. That is not a finding that amounts below a limit carry no risk for a particular child, and a pediatrician is the person to ask.²

Who should ask a doctor before a child or teen takes folate?

A pediatrician, before giving any folate supplement to a child.¹
A doctor, when a teen takes an anti-seizure medicine, methotrexate or sulfasalazine, which interact with folate.¹
A doctor, when a child eats no animal foods or has been diagnosed with low vitamin B12.²
A doctor or pharmacist, when a child already takes a multivitamin or eats fortified cereals, to add up the total against the upper limit for the child's age.^1,2

Questions people ask

Is folate safe for kids?

NIH sets upper limits for folate from supplements and fortified foods by age, from 300 mcg a day at ages 1 to 3 to 800 mcg at 14 to 18, and sets none for food folate. Ask a pediatrician before giving a supplement.^1,2

Is methyl folate safe for kids?

The sources checked do not address methylfolate in children. NIH describes it as an option for some people with the MTHFR C677T gene variant. Ask a pediatrician or pharmacist.^1,2

Is folic acid good for a teenage girl?

NIH says all teen girls who could become pregnant should get folic acid from supplements, fortified foods or both, and that 19% of girls aged 14 to 18 get less than the average requirement. Ask a doctor about your own situation.^1,2

Can a teenager take folic acid?

NIH sets an upper limit of 800 mcg a day for ages 14 to 18 from supplements and fortified foods, and says people should not exceed it unless a health care provider recommends it. Ask a doctor first.^1,2

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