There is a growing recognition of the importance of glutathione (GSH) physiology and the number of physiological functions involving this small but important tripeptide
However, unlike a simple under-the-skin injection, for an intramuscular injection you must stab the entire needle through the skin and into the muscle as close to the area of pain as possible
This could be daily, weekly, monthly, or at other intervals appropriate for your physiology
Clinics with experienced professionals and a strong track record often charge more, but they also provide a higher standard of care
Search terms like "vitamin B12 GLP-1 agonist," "cyanocobalamin absorption gastric emptying," and "B12 deficiency obesity surgery" yield relevant papers
This difference in mechanism is what makes the combination potentially valuable