McCullough et al., The Journal of Steroid Biochemistry and Molecular Biology,
doi:10.1016/j.jsbmb.2018.12.010 (Review) (Peer Reviewed)
Daily oral dosing of vitamin D3 using 5000 TO 50,000 international units a day in long-term hospitalized patients: Insights from a seven year experience
Report on the long-term use of vitamin D in hospitalized patients with daily dosing from 5,000 to 50,000IU over 7 years. There were no cases of hypercalcemia or any adverse events related to vitamin D supplementation. Authors conclude that long-term supplementation with vitamin D3 in doses ranging from 5,000 to 50,000 IUs/day appears to be safe.
McCullough et al., 1/1/2019, peer-reviewed, 3 authors.