What Is 5-MTHF?
Folate (vitamin B9) exists in dietary form as polyglutamate folates and in the active cellular form as 5-methyltetrahydrofolate (5-MTHF). The synthetic form in most supplements is folic acid—an oxidised, non-naturally-occurring form that requires reduction and methylation by multiple enzymes, with MTHFR being the most critical and frequently impaired.
5-MTHF (also called L-methylfolate, levomefolic acid, or the branded forms Metafolin, Quatrefolic) is the end-product that enters cells directly and participates immediately in the methionine cycle and nucleotide synthesis. No enzymatic conversion is required.
The MTHFR Problem
The MTHFR enzyme (methylenetetrahydrofolate reductase) is required to convert 5,10-methyleneTHF to 5-MTHF. MTHFR variants (C677T: ~30–40% of South Asians heterozygous, ~10–15% homozygous; A1298C: ~20–30% carrier rate) reduce enzyme activity by 30–70%. For MTHFR carriers consuming folic acid:
- Folic acid accumulates as unmetabolised folic acid (UMFA) in blood
- UMFA may competitively inhibit active folate receptors
- Homocysteine rises due to insufficient methyl groups for remethylation
- Neural tube defect protection is compromised in pregnancy
Solution: Replace all folic acid with 5-MTHF. This bypasses the MTHFR bottleneck entirely.
Neural tube defects (NTDs) are the second most common birth defect in India. Current guidelines recommend 400–800mcg folic acid pre-conception and early pregnancy. However, for MTHFR carriers (who cannot efficiently convert folic acid), switching to 5-MTHF ensures adequate active folate reaches the developing neural tube. Many Indian obstetricians now prescribe 5-MTHF-containing prenatal vitamins (e.g., Metanx, L-Methylfolate tablets). Women with prior NTD-affected pregnancy should use 5000mcg (5mg) 5-MTHF under medical supervision.
Frequently Asked Questions
What is the MTHFR gene mutation and why does it matter?
MTHFR (methylenetetrahydrofolate reductase) converts dietary folate to the active 5-MTHF needed for DNA synthesis, neurotransmitter production, and homocysteine clearance. Variants (C677T, A1298C) reduce enzyme activity by 30–70%. Consequences: elevated homocysteine (cardiovascular risk), impaired folate-dependent methylation (affects gene expression, neurotransmitter synthesis), increased NTD risk in pregnancy. ~40% of Indians carry at least one MTHFR variant—this is a common and clinically meaningful gene variant.
5-MTHF vs folic acid in India – which should I take?
5-MTHF is preferred for anyone with known MTHFR variants, elevated homocysteine, recurrent pregnancy loss, neural tube defect history, depression, or anyone wanting to be certain of adequate folate status. 5-MTHF bypasses MTHFR entirely and works regardless of genotype. Folic acid is fine for people with confirmed normal MTHFR function and adequate conversion capacity. Given the high MTHFR variant prevalence in India (~40%), 5-MTHF is a reasonable default choice.
Methylfolate for homocysteine reduction?
Yes—5-MTHF is a primary methyl donor for homocysteine remethylation to methionine (via MTR enzyme). Combined with methylcobalamin (B12) and B6 (P5P), the triple combination is the most effective supplement approach for homocysteine reduction: typically reduces homocysteine by 20–30%. Target: homocysteine below 10 μmol/L (optimal below 7). India's elevated cardiovascular and dementia burden makes homocysteine management a population-level priority.
Methylfolate dose for pregnancy in India?
Pre-conception and first trimester: 400–800mcg 5-MTHF/day minimum. For MTHFR heterozygotes: 800–1000mcg/day. For MTHFR homozygotes (C677T/C677T) or prior NTD history: 1000–5000mcg/day under medical supervision. Take with methylcobalamin B12 (500–1000mcg/day) for complete methylation cycle support. Begin at least 1 month pre-conception for best outcomes.