Vitamin D deficiency remnants a significant global health concern, functioning as a critical modulator of systemic physiological health beyond its established role in bone metabolism. This study investigates the physiological implications of Vitamin D deficiency among a sample of 100 participants , examining how serum 25-hydroxyvitamin D levels influence a spectrum of metabolic and biochemical markers. Following a literature review identifying Vitamin D as a key systemic regulator, serum analysis was conducted using the Cobas e411 for hormonal assessment and the Cobas c111 for biochemical profiling. The results revealed a varied impact: while significant correlations were observed between Vitamin D levels and specific parameters such as mineral homeostasis markers, other indicators exhibited non-significant changes, suggesting a selective physiological response to deficiency. These findings suggest that Vitamin D plays a more expansive role in maintaining internal equilibrium than is often prioritized in routine clinical settings. Consequently, the study concludes that maintaining optimal Vitamin D levels is essential for overall physiological integrity, emphasizing the importance of consistent diagnostic monitoring and targeted supplementation strategies. Key words: Vitamin D Deficiency, 25-Hydroxyvitamin D [25(OH)D], Physiological Parameters, Biochemical Markers.
