Myths vs facts: MTHFR and fatigue

Myths vs. facts: MTHFR and fatigue. MTHFR is a gene encoding an enzyme that converts folate into its active form. Social media often claims that certain MTHFR variants directly cause chronic fatigue. However, the scientific evidence is weak to mixed. While rare, severe MTHFR mutations can markedly elevate homocysteine and may be linked to fatigue, the common variants (C677T, A1298C) have not shown a clear, clinically relevant association with general tiredness in large studies. Fatigue is multifactorial: sleep deprivation, stress, iron deficiency, thyroid issues, vitamin D deficiency, or psychological factors are far more common. A DNA test for MTHFR alone does not explain fatigue. Many direct-to-consumer companies overstate the importance of these variants. A more useful approach is a medical workup with blood tests (ferritin, vitamin B12, folate, vitamin D, TSH). Evidence: mixed. Sources: No specific PMIDs in the given context.