Abstract: Methods and compositions for treating 25-hydroxyvitamin D insufficiency and deficiency in a patient are described herein. The method includes orally administering to the patient a delayed, sustained release formulation including a first ingredient selected from the group consisting of 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, or a combination of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3, or it includes gradually administering to the patient a sterile intravenous formulation including a first ingredient selected from the group consisting of 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, or a combination of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3.