Disclosed is a composition comprising a vitamin D analog, wherein the composition is characterized by being a solid preparation. The vitamin D analog is selected from one of vitamin D3, calcifediol, calcitriol, alfacalcidol, eldecalcitol, doxercalciferol, maxacalcitol, paricalcitol, tacalcitol and calcipotriol. The solid preparation produces an amount that is less than or equal to 7% of the corresponding precursor of the vitamin D analog after being shielded and stored at room temperature for 12 months.