When snorted like cocaine it can cause death. It is measured by percentage but that means nothing in and of itself. Some peppers are hotter than others as we have all noted at Mexican Restaurants. The Scovel taste scale runs from about 500,000 to a couple of million. May remember after more sleep.
Sprays work best on people who are surprised by it.
Chemical combinations of above are slightly better. Not many cops carry ultraviolet lights to detect it. It is okay. It shoots darts that may stick in the clothing or body of an assailant with wires attached. Capacitative shock delivered through wires.