This isn't something I've tried or even heard of but I've done a quick Google and it seems Celabolin is the trade name used by the Jersey company for a product containing either Celadrex or Celadrin. If you go to Amazon and search Celabolin it comes up with several products that seem similar. One in particular Celadrex Advanced has 18 customer reviews so might be worth a read!
Personally, I too tend to stick with what's prescribed. I'm not one for taking chances with my health, I've too many problems, or my money!! It would be interesting to hear what their claims of 'clinically proven' actually are. Sorry, I tend to be a bit cynical these days!
Lyn x