Definitely works if you give it time!
I have 7 cats and 3 of my girls all of a sudden starting marking outside litterbox and fighting and hissing, I was getting pretty desperate so I tried this , there was no change til week 2 or 3 but slowly I started to notice improvement, the biggest was my tiny grey tabby who was never affectionate has started to sit beside me and look for cuddles, I have had her for 2 years and she has never acted like this, the peeing has definitely reduced too but I’m attacking that with enzymes cleaners