Seems to be helping
The problem with reviewing this is you can't be certain if it is helping after a while, it just becomes a daily feed, if your cat has 'permanent' Cystitis, e.g. the moment you stop treatment, they need more, then you can be sure of continued help, as if it wasn't, the Cystitis would flare up again even though they are still on this.
But if like our cat, once the Cystitis is under control, she can go without any treatment at all, first time we went over 5 years without treatment, so worth trying