The body uses NAC to make glutathione. It’s safe and it works. it’s also an excellent antioxidant, and is great at breaking down mucus. NAC has long been used as a treatment for acetaminophen overdose. https://www.mdcalc.com/acetaminophen-overdose-nac-dosing It has been available over the counter for a long long time. Bottom line it got banned because it works. it’s now in clinical trials. Drug companies are looking for ways to make prescription medications to control mucus in Covid patients, and they don’t want anybody buying the stuff without a prescription. It’s ALL about profit. By the way it was taken off the market for a bit and is now available again, at least online. My guess is in the future it probably won’t be available at all. People who use it regularly are stocking up.