Is this the BioEos one you're talking about? I got the BioEos stuff from the National Sweet Itch centre last year; I can't say with any accuracy whether it improved the situation or not as my boy moved yards. However, I'm going to use it this coming year now he's home at my place for the foreseeable future, and see how it goes.
IMO its possible to throw good money after bad on various gunk that's supposed to be a fix, but the BioEos stuff did come very well recommended and from a (hopefully) reliable source. My boy certainly wasn't any worse and might well have been noticeably better, but again, changing location might have been the reason for this.
Be interesting to know if anyone else has trialled it?