Many studies have utilized oral, subcutaneous, and intramuscular injections for administration
Bersinger NA, Gnthert AR, McKinnon B, Johann S, Mueller MD
William Castle demonstrated that gastric juice contained an "intrinsic factor" which when combined with meat ingestion resulted in absorption of the vitamin in this condition
The new research cited NBC News previous reporting on med spas as evidence of rising concerns of their safety, with reports of infections and contaminated products. Of 255 clinic websites analyzed, more than half offered IV hydration therapy touting therapies like magnesium for headaches and muscle cramps, glutathione as a potential immune system booster, or other substances advertised to increase energy
Blankenberg S, Rupprecht HJ, Poirier O, Bickel C, Smieja M, Hafner G et al