How is glutathione given?
Besides intravenously you can also get glutathione from food, but you cannot ingest enough to really make a significant difference in your glutathione levels. You cannot ingest glutathione directly because firstly it will be broken down by your digestive system before it reaches your cells and secondly even if it did reach the cells the molecule is to large to penetrate the cell membrane.
You can ingest the parts your body needs to produce glutathione and let your body do the work from there.