This is how I know SN likely works.
I wanted to test my SN with blood. I picked myself on the arm and I couldn't bleed enough to drip, so I put a little SN on the open wound. The blood instantly changed to a dark chocolate brown, and then in about five minutes my arm felt warm and the feeling went up my arm and down to my chest, it got slightly more difficult to breathe, and my head felt like the beginning sensations of passing out. I drank a bunch of water and all the symptoms subsided. So if you want to know for yourself, don't take my word for it, do what I did, but do it at your own risk. You can take it as a cautionary tale that SN is poison, or do it to see if you get any of the listed symptoms of an SN OD.