The recommended dose for vitamin D supplements is much larger today than it was a few years ago. For example, it is not too uncommon to recommend an average dose of a 50,000 (IU) international unit of vitamin D Dry Water Miscible (Water Soluble) by mouth on a daily basis after the duodenal switch operation. Since vitamin D is a fat soluble vitamin, it is important that the appropriate type be utilized. Dry formulation of vitamin D is needed to ensure adequate absorption. There are a number of manufacturers that produce these. When searching for one “Dry” D3-50 the patient would be looked for. Some larger supplement manufacturer’s carry these products. The links to these manufacturers is located here.