Is LCT useful for Müdigkeit?

Whether the LCT gene (lactase persistence) is useful for fatigue is not supported by strong evidence. LCT determines your ability to digest lactose in dairy. Lactose intolerance can cause bloating, diarrhea, and abdominal pain, but a direct link to fatigue is not established in human trials. There is a weak mechanistic possibility: undigested lactose may trigger low-grade inflammation or malabsorption, which could theoretically affect energy levels. However, fatigue is multifactorial (sleep, diet, stress, iron deficiency, thyroid, etc.), and LCT genotype alone is not a reliable predictor. Consumer DNA tests like MyBody-X do not provide clinically actionable information for fatigue based on LCT. If you experience persistent tiredness, consult a doctor for a comprehensive workup rather than relying on a single genetic marker.