The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (over 18 years old)
U.S. Recommended Dietary Allowance (RDA) for adults (oral) : Four hundred micrograms daily for males or females ages 14 years and older; 500 micrograms daily for breastfeeding adult women; 600 micrograms daily for pregnant adult women. Given as dietary folate equivalents (DFE).
Tolerable upper intake levels (UL) daily : The UL is the maximum daily level of intake that is likely not to pose a risk of adverse effects. The UL is 800 micrograms daily for males or females ages 14-18 years-old (including pregnant or breastfeeding women); and 1,000 micrograms daily for males or females ages 19 years and older (including pregnant or breastfeeding women).
Adjunct treatment with conventional antidepressants : Doses of 200 to 500 micrograms daily has been used for enhancing treatment response to antidepressants. Limited clinical research suggests that folic acid is not effective as a replacement for conventional antidepressant therapy.
Anticonvulsant-induced folate deficiency : Fifteen milligrams (15,000 micrograms) daily has been used under the supervision of a qualified healthcare provider.
Cervical cancer : Doses of 0.8 to 10 milligrams (800 to 10,000 micrograms) daily have been used.
Colon cancer : Doses of 400 micrograms daily have been used to reduce the risk of colon cancer occurring, although supplementation has not been proven to be effective.
Depression : Doses of 500 micrograms folic acid or 15-50 milligrams methylenetetrahydrofolate daily, as adjunct treatment with conventional antidepressants.
Drug-induced toxicity : For reduction of toxicity symptoms (nausea and vomiting) associated with methotrexate therapy for rheumatoid arthritis (RA) or psoriasis, 1 milligram daily (1,000 micrograms daily) may be sufficient, but up to 5 milligrams daily (5,000 micrograms daily) may be used.
End stage renal disease (ESRD) : Doses of 0.8 to 15 milligrams (800 to 15,000 micrograms) folic acid daily are generally used, but the degree of homocysteine reduction is very variable (between 12%-50%), and normal homocysteine levels (<12 micromoles per liter) may not always be achieved. Folic acid 2.5 to 5 milligrams (2,500 to 5,000 micrograms) three times weekly also reduces homocysteine levels in ESRD patients on dialysis. Doses greater than 15 milligrams (15,000 micrograms) daily do not provide additional benefit. Doses of 30 to 60 milligrams (30,000 to 60,000 micrograms) seem to cause a rebound in homocysteine levels when treatment is stopped.
Folate deficiency : The typical dose is 250 to 1,000 micrograms daily. For severe folate deficiency, such as in cases of megaloblastic anemia and malabsorption disorders, 1-5 milligrams (1,000 to 5,000 micrograms) daily is often used until corrected blood tests are documented by a qualified healthcare professional.
Hyperhomocysteinemia : Doses of 0.2 to 5 milligrams daily (500 to 15,000 micrograms) have been used, although 0.8 to 1 milligrams daily (800 to 1,000 micrograms) appears to provide maximal reduction of homocysteine levels. Doses greater than 1 milligram daily (1,000 micrograms) do not seem to produce any greater benefit except in some people with certain gene mutations that cause homocysteine levels of 20 micromoles per liter or higher. However, initial data suggest that the U.S. government-mandated fortification of cereals and flour with 140 micrograms folic acid per 100 grams is reducing the mean homocysteine level in the general population by about 7%. Consumption of at least 300 micrograms daily of dietary folate seems to be associated with a 20% lower risk of stroke and a 13% lower risk of cardiovascular disease when compared with consumption of less than 136 micrograms of folate daily. Doses of 10 milligrams (10,000 micrograms) daily of folic acid have been used to improve coagulation status, oxidative stress, and endothelial dysfunction.
Hypertension : Doses of 5-10 milligrams daily folic acid.
Megaloblastic anemia : In cases of megaloblastic anemia resulting from folate deficiency or malabsorption disorders such as sprue, oral doses of 1 to 5 milligrams (1,000 to 5,000 micrograms) daily may be used until hematologic recovery is documented by a qualified healthcare provider.
Methotrexate toxicity : Doses of 1-27.5 milligrams weekly folic acid or 1-20 milligrams weekly folinic acid.
Neural tube defects (prevention) : Doses of at least 400 micrograms of folic acid daily from supplements or fortified food should be taken by women capable of becoming pregnant and continued through the first month of pregnancy. Women with a history of previous pregnancy complicated by such neural tube defects usually take 4 milligrams (4,000 micrograms) daily beginning one month before and continuing for three months after conception under the guidance of a qualified healthcare professional. Doses of 0.36-5 milligrams daily folic acid.
Pancreatic cancer : Consuming greater than 280 micrograms daily of dietary folate is associated with a decreased risk of exocrine pancreatic cancer. Further research is needed to confirm these results.
Phenytoin-induced gingival hyperplasia : Applying folic acid topically may inhibit gingival hyperplasia secondary to phenytoin therapy. However, taking folic acid by mouth does not seem to be beneficial for this indication.
Pregnancy-related gingivitis : Applying folic acid topically may improve gingivitis in pregnancy.
Preventing increases in homocysteine levels after nitrous oxide anesthesia : Folate 2.5 milligrams (2,500 micrograms) in combination with pyridoxine 25 milligrams (25,000 micrograms) and vitamin B12 500 micrograms have been used daily for one week before surgery under the supervision of a qualified healthcare provider.
Stroke : Doses of 0.5-15 milligrams folic acid daily.
Vitiligo : Doses of 5 milligrams (5,000 micrograms) have been taken twice daily.
Children (under 18 years old)
U.S. RDA or Adequate Intake (AI) for children (oral) : For infants 0-6 months-old, the AI is 65 micrograms daily; for infants 7-12 months-old, the AI is 80 micrograms daily; for children 1-3 years-old, the RDA is 150 micrograms daily; for children 4-8 years-old, the RDA is 200 micrograms daily; for children 9-13 years-old, the RDA is 300 micrograms daily. Given as dietary folate equivalents (DFE).
Tolerable (UL) daily : The UL is the maximum daily level of intake that is likely not to pose a risk of adverse effects. For children 1-3 years-old, the UL is 300 micrograms; for children 4-8 years-old, the UL is 400 micrograms; for children 9-13 years-old, the UL is 600 micrograms; for adolescents 14-18 years-old, the UL is 800 micrograms.
Caution : Folic acid injection contains benzyl alcohol (1.5%) as a preservative, and extreme care should be used in administration to neonates. Folic acid injections should be administered by a qualified healthcare provider.