How can calcitriol deficiency cause osteoporosis?

Calcitriol is VitD : Vitmin d makes calcium absorption possible from the GI tract. Lack of it causes uncalcified bone to grow which is very weak and causes osteomalacia, a metabolic bone disorder. In children the disorder is rickets; adults get weak bones. It is cured by taking vitamin d by mouth.

Take D3 unless......: Take d3 unless your have kidney disease, or take certain anticonvulsants, which will block the formation of Calcitriol (1-25, dyhydroxy d). There are metabolites of d3 that may be helpful, and contribute to the many benefits of d! but without calcitriol, osteoporosis will ensue!