In this 2005 publication by the CDC, titled "Chloroquine is a potent inhibitor of SARS coronavirus infection and spread" https://stacks.cdc.gov/view/cdc/3620, they talk about the function of chlorquine as an ionophore for zinc and how it more or less wipes out SARS, a corona virus. Curiously, they also talk about ammonium chloride having the same effect. These tests are mostly in vitro, so the the concentrations of NH4Cl would probably be too high to be ingested.
This is very strange. Ammonium chloride, what caused them to try this? When I was a little boy, I did a lot of chemistry experiments, many of them unwise. NH4Cl is inexpensive and used in a lot of things, such as cough drops, soldering iron retinning blocks, baking, and candy making. I loved the stuff because if you heat it up it decomposes temporarily and recomposes as white mist or smoke. The smoke deposits itself on any surface it comes into contact with making it a bright dead white. Lotsa fun. I used to inhale a little bit of it just to get sort of a funny tingle or to break up the congestion in my lungs when I had a cold. No one told me to do this and my parents would not have been amused if they had found out. But think about this. Ammonium chloride is not only a zinc ionophore, it's a mucolytic. It breaks up mucous. In viral pneumonia, the thing that people die of is mucous deposited between the alvioli and the capillaries, thereby cutting off the exchange of oxygen and carbon dioxide. Could this work? I'm sure no one will try it. Too simple and maybe too dangerous.