Form Comparison

Folinic Acid vs L-Methylfolate

How folinic acid and L-methylfolate differ in potency, absorption, tolerance, and cost.

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Quick verdict. Methylfolate is the end product and bypasses both DHFR and MTHFR; folinic acid bypasses DHFR but still passes through MTHFR. That makes methylfolate the better pick for reduced MTHFR activity, and folinic acid the better pick when drugs like methotrexate block DHFR or when methylfolate causes side effects. Both can mask the anemia of B12 deficiency, so check B12 status first.

Side by Side

Folinic Acid L-Methylfolate
Absorption High High
How it is absorbed A reduced folate that bypasses DHFR. It still passes through MTHFR to become methylfolate. The main circulating form of folate. Bypasses both DHFR and MTHFR, so reduced MTHFR activity (as with the TT genotype) does not limit its use.
Typical dose 400-800 mcg daily as a supplement; higher prescription doses 400-1,000 mcg daily
Common uses methotrexate rescue (prescription), people who react to methylfolate MTHFR variants, avoiding unmetabolized folic acid, adjunct in depression (prescription doses)
Side effects Well tolerated. Well tolerated. Can also mask B12 deficiency anemia.
Cost Moderate Moderate
Also called leucovorin, calcium folinate, 5-formyltetrahydrofolate 5-MTHF, L-5-methyltetrahydrofolate, Metafolin, Quatrefolic
Labels in index 11 140

When to Choose Folinic Acid

Choose folinic acid when a clinician wants a reduced folate without the methyl group. Useful when DHFR is inhibited by drugs such as methotrexate or trimethoprim.

Folinic Acid

Choose folinic acid when a clinician wants a reduced folate without the methyl group.

What to look for: Folinic Acid named on the Supplement Facts panel, with the amount per serving stated.

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When to Choose L-Methylfolate

Choose L-methylfolate when you have an MTHFR variant or want to avoid unmetabolized folic acid. Sold as calcium or glucosamine salts. Check whether the label states mcg of the compound or mcg DFE.

L-Methylfolate

A reasonable alternative that avoids unmetabolized folic acid. Its advantage for MTHFR variant carriers is theoretical.

What to look for: A named salt (Metafolin or Quatrefolic) with mcg DFE stated, at doses near 400-1,000 mcg rather than the milligram range.

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Products on Titrate

In Titrate's index of NIH label data, 11 labels named as folate products list folinic acid and 140 list L-methylfolate.

Open supplement search

Supplement Search loads one category at a time. Choose the B-Complex tab, then type a form such as "folic acid" under Must contain, or a form to avoid under Must not contain.

Related

References

NIH Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals.

MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet. 1991;338(8760):131-137.

Williams J, et al. Updated estimates of neural tube defects prevented by mandatory folic acid fortification: United States, 1995-2011. MMWR Morb Mortal Wkly Rep. 2015;64(1):1-5.

Pfeiffer CM, et al. Unmetabolized folic acid is detected in nearly all serum samples from US children, adolescents, and adults. J Nutr. 2015;145(3):520-531.

US Preventive Services Task Force. Folic Acid Supplementation to Prevent Neural Tube Defects: US Preventive Services Task Force Reaffirmation Recommendation Statement. JAMA. 2023;330(5):454-459.