Glutathione half life is roughly ten minutes. So an IM shot is done working quickly. IV you can extend that half life by a constant drip. Also the amount absorbed by your body is higher by IV. You are not getting 100% absorption with IM.
I have read that Glutathione IM and NAC has a build up phase. This I’m not sure about. NAC the oral version does have a build up phase.
The oral is useless. Your better off chewing on tree bark and saving money.
www.defymedical.com sells pharma Glutathione. You fill out a couple forms and you can order any vitamins you want. Shipping for refrigerated products are $40.00 and Glutathione is $77 for 30 ml.