What role does Homocystein play in Müdigkeit?

Homocysteine is a sulfur-containing amino acid produced during methionine metabolism. Elevated homocysteine (hyperhomocysteinemia) is a well-established risk factor for cardiovascular disease and has been linked to fatigue, but the evidence for a direct causal role in fatigue is indirect and mixed. Potential mechanisms include impaired methylation (due to deficiencies in vitamin B12, B6, or folate), endothelial dysfunction, and increased oxidative stress, all of which could contribute to feelings of tiredness. In clinical practice, homocysteine is sometimes measured in fatigue workups, especially when vitamin deficiency or methylation disorders are suspected. However, large randomized trials have not consistently shown that lowering homocysteine with B-vitamin supplementation improves fatigue symptoms. Consumer DNA tests often include MTHFR variants, which can modestly influence homocysteine levels, but the effect is small and not diagnostic. For persistent fatigue, a blood test for homocysteine is more informative than genetic testing. Interpretation should be done by a physician, considering renal function, thyroid status, and lifestyle factors. Overall, while homocysteine is a relevant biomarker, its role in fatigue is not straightforward and requires a comprehensive clinical assessment.