Apaydin M, et al. - In postmenopausal women with vitamin D deficiency or insufficiency, researchers compared the effects and safety of single high-dose with daily low-dose oral colecalciferol on 25(OH)D levels and muscle strength via analyzing data of 60 healthy postmenopausal women who had serum vitamin D levels < 20 ng/mL (50 nmol/L). According to the findings obtained, a single administration was more effective in increasing vitamin D levels although daily administration routes were more effective in improving muscle strength.