Just my opinion but I think the UV Killer is one of the few products that really work, No, I don't have any way to prove it other than experiences that lead me to believe in it. My hunting clothes don't get washed that often, but when they do it is in Sport wash, & then sprayed down with UV KIller. If I purchase something new it gets the same treatment, If it is a gimmick, well they got me, But I think it works, jmop Doc