Vitamin D3-d3 is the deuterium labeled Vitamin D3. Vitamin D3 (Cholecalciferol; Colecalciferol) is a naturally occuring form of vitamin D. Vitamin D3 induces cell differentiation and prevents proliferation of cancer cells.
Calcitriol-d3 is the deuterium labeled Calcitriol[1]. Calcitriol is the most active metabolite of vitamin D and also a vitamin D receptor (VDR) agonist[2][3][4][5].