A Comprehensive Monograph on Cholecalciferol (Vitamin D3): From Molecular Structure to Clinical Application

Executive Summary

Cholecalciferol, commonly known as Vitamin D3, is a fat-soluble secosteroid that functions as a critical prohormone within the human body. While historically classified as a vitamin, its endogenous synthesis in the skin upon exposure to sunlight and its subsequent multi-organ activation into a potent hormone underscore its central role in a complex endocrine system. The primary and undisputed function of the Vitamin D system is the maintenance of calcium and phosphate homeostasis, which is essential for normal bone mineralization. Consequently, Cholecalciferol is a cornerstone therapy for the prevention and treatment of a range of skeletal disorders arising from its deficiency, including rickets in children, osteomalacia in adults, and as an adjunct with calcium for osteoporosis management.

A significant body of scientific evidence has established the clinical superiority of Cholecalciferol (D3) over its plant-derived counterpart, Ergocalciferol (D2). Studies consistently demonstrate that D3 is more potent and has a longer duration of action in raising and sustaining serum concentrations of 25-hydroxyvitamin D, the key indicator of vitamin D status. This has led to a broad consensus that Cholecalciferol should be the preferred form for both supplementation and therapeutic repletion.