7-デヒドロコレステロールは天然ステロールであり、ビタミン D₃ の生物学的前駆体であり、ヒトのビタミン D 生合成において重要な役割を果たします。 The conjugated diene group of 7-Dehydrocholesterol absorbs UV radiation in the wavelength range of 250-310 nm, leading to the opening of the B-ring of the steroid nucleus and the formation of provitamin D₃ . 7-Dehydrocholesterol is synthesized in the skin from cholesterol and transported to the skin surface, where exposure to UVB radiation converts it to an activated form of the vitamin precursor (cholecalciferol) . In addition to its role in vitamin D biosynthesis, 7-Dehydrocholesterol serves as a critical intermediate in the synthesis of various steroid hormones and bile acids, and is used as a reference standard in pharmaceutical analysis for vitamin D-related compounds .