Evidence check: MTHFR in the context of Schlaf

The link between MTHFR variants (e.g., C677T) and sleep is not well-established. Some studies suggest a possible association with sleep apnea or insomnia, mediated by elevated homocysteine or impaired methylation. However, effect sizes are small, findings are inconsistent, and often not replicated in general populations. Direct-to-consumer tests that derive sleep recommendations from a single MTHFR SNP significantly overstate the evidence. Clinical relevance remains unclear; genotyping alone does not warrant specific sleep interventions. Instead, focus on proven factors like sleep hygiene, stress reduction, and medical evaluation of sleep disorders. Folate or vitamin B12 deficiency can affect methylation, but evidence for sleep outcomes is weak. Conclusion: MTHFR in the context of sleep is an area of moderate but insufficient evidence for personalized advice.