I've noticed some ostomy deoderants have DMDM HYDANTOIN in them which is a formaldehyde releaser. They put it in there to kill bacteria but how safe could this be so close to a stoma and if your a rinser. I think M9 in my experience has been the safest and most effective.
I found one shampoo I was using had this in it as well and had class action lawsuits over it. Of course i ditched it.
These days we have to watch everything in our products. Like all of our products.