An active metabolite of vitamin D3 that activates the vitamin D receptor (VDR). Plays important role in regulating body levels of calcium and phosphorus, and in mineralization of bone. It has widespread effects on cellular differentiation and proliferation, and can modulate immune responsiveness, and central nervous system function. Known to act as a chemopreventive agent against several malignancies including cancers of the prostate and colon and shows synergy with other anticancer compounds. MW: 416.64. Purity ≥99% by HPLC