Methylation is a biochemical process that governs DNA repair, neurotransmitter production, detoxification, and immune function. It occurs billions of times per second in every cell. When methylation runs efficiently, these systems function well. When impaired — by genetic variants or nutrient deficiencies — the downstream effects can influence energy, mood, cardiovascular health, and how your body processes stress.

MTHFR encodes an enzyme that converts folate into its active form (5-MTHF), which drives the methylation cycle. The C677T and A1298C variants reduce enzyme activity, affecting folate metabolism, homocysteine regulation, and B-vitamin utilization. Approximately 40–60% of the population carries at least one MTHFR variant, making it among the most clinically discussed genes in functional and preventive medicine.

Homocysteine accumulates when the methylation cycle runs inefficiently. The cycle normally converts homocysteine back to methionine using 5-MTHF, methylcobalamin (B12), and B6. When MTHFR, MTRR, or CBS variants reduce conversion — or when these nutrients are insufficient — homocysteine rises. Elevated homocysteine is associated with increased cardiovascular risk, cognitive decline, and pregnancy complications, making it a key functional marker alongside genetic testing.

Folic acid is synthetic and requires conversion by the MTHFR enzyme to become biologically active (5-MTHF). Individuals with MTHFR variants may convert it poorly. Methylfolate (5-MTHF) is the pre-converted, bioavailable form that bypasses the MTHFR step entirely. For anyone with known methylation variants, methylfolate is the preferred form — found in quality supplements rather than most standard fortified foods.

A genetic methylation test reveals your inherited tendencies — which variants you carry in MTHFR, COMT, MTRR, and related genes. It shows predisposition, not current function. For a complete picture, genetic testing pairs with a Methylation Panel Blood Test measuring active biomarkers like homocysteine, folate, and B12 — showing how your methylation cycle is actually performing right now.