Absorption with IVs is much higher than absorption with any oral options. The intestine where absorption takes place for most nutrients. For a variety of reasons, like gastrointestinal disorders like IBS, and lack of healthy gut bacteria due to antibiotic use, many bodies don’t adequately absorb vitamins and minerals. Called malabsorption, can lead to many problems, like low energy levels, and low electrolyte levels, along with frequent illness. When vitamins and minerals are taken intravenously, they bypass the problems associated with the GI tract and are able to be fully absorbed by tissues in the body.