What medicines contain folic acid?

October 13, 2025 •

4 min read

Since 1998, federal law has required the addition of folic acid to cold cereals, flour, breads, and pasta to combat deficiency [1.5.3]. But beyond fortified foods, what medicines contain folic acid? This essential B vitamin is available in various forms, from prenatal vitamins to high-dose prescription medications.

Quick Summary

Folic acid is available as a single-ingredient supplement, in multivitamins, prenatal formulas, and as a high-dose prescription. It's used to treat deficiency, prevent birth defects, and manage side effects of other medications like methotrexate.

Key Points

Prescription & OTC: Folic acid is available both over-the-counter (400-1000 mcg) and as a high-dose prescription (1-5 mg) under brand names like Folvite [1.2.1, 1.3.3].
Pregnancy: Daily supplementation of 400-800 mcg is recommended for all who could become pregnant to prevent neural tube defects [1.8.1].
Drug-Induced Deficiency: Medications like methotrexate, certain antiepileptics (phenytoin), and metformin can deplete the body's folic acid levels [1.6.2, 1.6.3, 1.10.3].
Active vs. Synthetic Forms: Folic acid is synthetic and needs conversion, while L-methylfolate is the body's active form, bypassing potential conversion issues from the MTHFR gene mutation [1.4.1].
Anemia Treatment: Folic acid is FDA-approved to treat specific types of anemia (megaloblastic and macrocytic) caused by folate deficiency [1.5.5].
Methotrexate Rescue: A form of folic acid called leucovorin is used as a "rescue" therapy to protect healthy cells from high-dose methotrexate treatment in cancer patients [1.2.2].
Drug Interactions: Folic acid supplements can reduce the effectiveness of certain seizure medications like phenytoin and other drugs like pyrimethamine [1.7.1].

Understanding Folic Acid in Medicine

Folic acid is the synthetic, man-made form of folate, a crucial B vitamin (B9) [1.4.1]. While folate is found naturally in foods like leafy greens and legumes, folic acid is used in supplements and fortified foods due to its stability [1.4.1, 1.4.5]. Its most vital role is in the synthesis of DNA and RNA, and the metabolism of amino acids, which are processes essential for cell growth and division [1.6.2, 1.4.4]. This is particularly critical during periods of rapid growth, such as pregnancy [1.4.1]. The U.S. Preventive Services Task Force recommends that all individuals planning or capable of pregnancy take a daily supplement with 400 to 800 mcg of folic acid to prevent neural tube defects [1.8.1]. This supplementation should begin at least one month before conception and continue through the first few months of pregnancy [1.8.1].

Prescription Medications with Folic Acid

High-dose folic acid is available by prescription to treat specific medical conditions. It is FDA-approved for treating megaloblastic and macrocytic anemias that result from folate deficiency [1.5.5]. Dosages for these conditions typically range from 1 mg to 5 mg daily [1.5.5]. Brand names for prescription folic acid include Folvite and Folacin-800 [1.2.1].

Folic acid is also a critical component in combination with other drugs:

With Methotrexate: Patients taking methotrexate for conditions like rheumatoid arthritis or cancer are often prescribed folic acid to reduce the drug's side effects, such as nausea and mouth sores [1.5.3, 1.5.5]. Methotrexate is a folate antagonist, meaning it blocks the action of folate in the body [1.6.4].
Leucovorin Rescue: In cases of high-dose methotrexate cancer therapy, a different form of folic acid called leucovorin (folinic acid) is used as a "rescue" agent. It's administered to protect healthy cells from the toxic effects of methotrexate [1.2.2, 1.9.1]. Leucovorin is a more active form that can be used by the body more directly [1.4.5].
Combination Products: Folic acid is also included in prescription-strength combination products, such as those with iron for treating certain anemias (e.g., Hemocyte-F, Ferrocite F) or with other vitamins for specific deficiencies [1.2.1].

Over-the-Counter (OTC) Folic Acid

Folic acid is widely available over-the-counter, primarily in the form of dietary supplements. These come in several varieties:

Standalone Supplements: You can buy tablets containing only folic acid, with common dosages being 400 mcg, 800 mcg, and 1000 mcg (1 mg) [1.3.1, 1.3.3]. Brands like Nature Made, CVS Health, and Nutricost offer these products [1.3.1, 1.3.2, 1.3.3].
Multivitamins: Most general multivitamins contain the recommended daily amount of folic acid (around 400 mcg).
Prenatal Vitamins: These are specifically formulated for pregnant individuals and typically contain higher levels of folic acid, often 600 mcg to 1 mg, to support fetal development and prevent birth defects like spina bifida [1.5.3, 1.8.3].
B-Complex Vitamins: These supplements group several B vitamins together, including folic acid, to support overall energy metabolism and nervous system health [1.3.3].

Folic Acid vs. Folate vs. Methylfolate

It's important to distinguish between the different forms of vitamin B9:

Folate: The natural form found in food. It's less stable and bioavailable than folic acid [1.4.5].
Folic Acid: The stable, synthetic form used in supplements and food fortification. The body must convert it into an active form [1.4.1].
Methylfolate (L-methylfolate or 5-MTHF): The biologically active form of folate. The body can use it immediately without conversion [1.4.1]. Some people have a genetic mutation (MTHFR gene) that makes it difficult to convert folic acid into methylfolate, making direct supplementation with methylfolate potentially more effective for them [1.4.1, 1.4.4]. Prescription medical foods like Deplin contain L-methylfolate and are used for conditions like depression and folate deficiency [1.2.4].


Feature	Folic Acid	Folate	L-Methylfolate (5-MTHF)
Source	Synthetic (supplements, fortified foods) [1.4.1]	Natural (leafy greens, legumes) [1.4.5]	Synthetic (supplements, medical foods) [1.4.1]
Form	Inactive, requires conversion [1.4.1]	Natural, requires conversion [1.4.4]	Biologically active, no conversion needed [1.4.1]
Stability	Highly stable [1.4.1]	Unstable, degraded by heat/light [1.4.1]	Stable in supplement form [1.4.1]
MTHFR Gene Impact	Conversion may be inefficient in individuals with MTHFR mutations [1.4.1]	Conversion can also be affected [1.4.1]	Bypasses the MTHFR conversion step, readily usable [1.4.1]
Common Use	General supplementation, food fortification, pregnancy [1.5.3]	Dietary intake	Recommended for MTHFR mutations, depression [1.2.4, 1.4.1]

Medications That Affect Folic Acid Levels

Certain medications can interfere with the body's absorption or metabolism of folic acid, potentially leading to a deficiency. These include:

Antiepileptic Drugs: Medications like phenytoin, carbamazepine, and phenobarbital can reduce folate levels significantly [1.10.1, 1.10.3].
Methotrexate: As a folate antagonist, it directly interferes with folate metabolism [1.6.4].
Sulfasalazine: Used for ulcerative colitis, this drug can interfere with the intestinal absorption of folate [1.6.4, 1.7.3].
Metformin: A common diabetes medication that can decrease levels of both vitamin B12 and folic acid [1.6.3].
Acid Blockers: Proton pump inhibitors (PPIs) and H2 blockers may interfere with nutrient absorption, including folic acid [1.6.5].

Conversely, taking folic acid supplements can also interact with some medications, potentially making them less effective. This includes certain anticonvulsants like phenytoin and the antimalarial drug pyrimethamine [1.7.1, 1.7.2].

Conclusion

Medicines containing folic acid range from widely available over-the-counter supplements and multivitamins to specific high-dose prescription drugs. Its primary role is to prevent and treat folate deficiency, ensure healthy fetal development, and mitigate the side effects of other medications. Whether as a standalone supplement like Nature's Bounty, a key ingredient in prenatal vitamins, or a prescription like Folvite, folic acid is a cornerstone of public health and targeted medical therapy. Understanding its different forms—folic acid, folate, and methylfolate—and its interactions with other drugs is essential for safe and effective use. Always consult with a healthcare provider to determine the appropriate form and dosage for your individual health needs.

For more information on the U.S. recommendations for folic acid, you can visit the CDC's page on Folic Acid.

Frequently Asked Questions

Folate is the natural form of vitamin B9 found in foods like leafy greens. Folic acid is the synthetic, stable form used in supplements and fortified foods because it's more easily absorbed, though it must be converted by the body to its active form [1.4.1, 1.4.5].

Common brand names for prescription folic acid include Folvite, Folacin-800, and FA-8. It is also found in combination drugs like Hemocyte-F [1.2.1].

Methotrexate is a folate antagonist that can cause side effects like nausea and mouth sores. Taking folic acid helps reduce these toxic effects without compromising the drug's primary function in treating conditions like rheumatoid arthritis [1.5.3, 1.5.5].

The U.S. Preventive Services Task Force and CDC recommend a daily supplement of 400 to 800 micrograms (mcg) for anyone planning or capable of becoming pregnant, starting at least one month before conception [1.8.1, 1.8.3].

L-methylfolate (5-MTHF) is the biologically active form of folate that the body can use immediately without conversion. It is often recommended for individuals with an MTHFR gene mutation that impairs the conversion of folic acid [1.4.1].

Since 1998, many grain products like bread, cereal, and pasta have been fortified with folic acid [1.5.3]. However, to prevent neural tube defects, a daily supplement is still recommended for those who could become pregnant to ensure consistent intake [1.8.1].

Several medications can deplete folic acid, including certain anti-seizure drugs (phenytoin, carbamazepine), metformin, sulfasalazine, and acid blockers like proton pump inhibitors [1.6.2, 1.6.3, 1.6.4, 1.6.5].