Quoted By:
>Excessive exposure to sunlight poses no risk in vitamin D toxicity through overproduction of vitamin D precursor, cholecalciferol, regulating vitamin D production. During ultraviolet exposure, the concentration of vitamin D precursors produced in the skin reach an equilibrium, and any further vitamin D that is produced is degraded.[7] This process is less efficient with increased melanin pigmentation in the skin.
>Endogenous production with full body exposure to sunlight is comparable to taking an oral dose between 250 µg and 625 µg (10,000 IU and 25,000 IU) per day.[7][8]
>Vitamin D oral supplementation and skin synthesis have a different effect on the transport form of vitamin D, plasma calcifediol concentrations. Endogenously synthesized vitamin D3 travels mainly with vitamin D-binding protein (DBP), which slows hepatic delivery of vitamin D and the availability in the plasma.[9] In contrast, orally administered vitamin D produces rapid hepatic delivery of vitamin D and increases plasma calcifediol.[9]
