Typically, nutrients reach your cells through the process of digestion. Your gastrointestinal (GI) tract breaks down the food you eat (or the pills you swallow) and passes the nutrients along to the blood through the lining of the GI tract. If your digestion is weak or if your gut cannot process high concentrations of a nutrient, your gut can become upset or simply excrete the nutrient without sending it along to the blood, where it can reach the cells that need it. When nutrients are infused directly into the bloodstream, they bypass the GI and are carried directly to the needy cells via the blood.
Intravenous treatments are exceptionally powerful because they circumvent issues with oral administration, including stomach upset, absorption issues and loss of potency. In addition, very large doses can be administered via IV without gastrointestinal side effects, which can limit dosing. A perfect example of this is vitamin C, which can only be taken in fairly small amounts orally before causing stomach upset. In contrast, very large doses of vitamin C, which can be very beneficial for the immune system, can be administered safely and without stomach side effects with an intravenous delivery route.