Merck, 803103-1ML, 25-Hydroxyvitamin D3-23,24,25,26,27-¹³C₅ solution

25-Hydroxyvitamin D₃ (calcifediol) is a prohormone produced via hydroxylation of vitamin D₃ (cholecalciferol) in the liver. It is a precursor for the synthesis of calcitriol {1,25-dihydroxyvitamin D₃ or [1,25(OH)₂D₃]}. It is used as a biomarker to determine the status of vitamin D in the body. 25-Hydroxyvitamin D₃-23,24,25,26,27-¹³C₅ is an isotope of vitamin D₃ wherein C-23, C-24, C-25, C-26, C-27 carbons are replaced by ¹³C₆ isotope.