Uses

L-methylfolate is the active, directly bioavailable form of folate. It is used to treat folate deficiency, as adjunctive therapy in depression (particularly in patients with MTHFR polymorphisms), and for prevention of neural tube defects.

Do not use if

Contraindicated in known hypersensitivity to l-methylfolate or any excipients. Use with caution in patients suspected of vitamin B12 deficiency, as folate supplementation may mask hematologic signs while neurologic damage progresses.

Side effects

Generally well tolerated. Rare adverse effects include gastrointestinal upset, insomnia, irritability, or allergic reactions. In folate-deficient patients receiving high doses, neuropathy may be unmasked if concurrent vitamin B12 deficiency is present.

Warnings

Ensure vitamin B12 status is evaluated before starting therapy to avoid masking pernicious anemia or B12-deficiency neuropathy. The FDA grounding provided was for a pediatric multivitamin product and is not specifically for l-methylfolate alone; clinical guidance is based on general folate pharmacology.

How it works

L-methylfolate (5-methyltetrahydrofolate) is the predominant circulating form of folate and the only form that crosses the blood-brain barrier. It bypasses the MTHFR enzymatic conversion step and directly participates in one-carbon metabolism, essential for DNA synthesis, amino acid methylation, and neurotransmitter synthesis.

Storage

Store at controlled room temperature (20°C to 25°C), protected from light, moisture, and excessive heat.