Evidence check: VDR in the context of fatigue

The VDR FokI variant (rs2228570) affects the function of the vitamin D receptor. Vitamin D is involved in immune regulation, muscle function, and cellular energy. Some studies suggest certain VDR variants may be associated with increased fatigue or exhaustion, especially when combined with low vitamin D levels. However, effect sizes are small and not sufficient for clinical diagnosis. Fatigue has many causes (sleep, stress, diet, other genes). A DNA test alone cannot explain fatigue. Evidence is based on observational studies, not RCTs. Without a blood test for vitamin D levels, the predictive value is limited. Caution: Do not self-medicate with vitamin D without medical advice.