Alum is added to tap water and to lakes/ponds, and of course to baking powder. I will not eat or drink any of that stuff.
I reseached this alum topic extensively years ago and could not really come to a definitive conclusion on whether or not to use it as a deodorant. It does work well to stop odor. One thing I found only from experience though is that the alum deodorant tends to form white alum dust inside the shirt, which can easily be seen inside a dark colored shirt at the end of the day. I think some of this dust is inhaled during the day and when sleeping at night and moving around. Sometimes I notice a difference when not using it as far as breathing/throat/lungs. I should stop using it. Back to the drawing board.
I will try colloidal silver. Thanks Luella.
(can topical colloidal silver cause problems if used too much, such as that blue skin issue?)