I think it has turned mine into a three year old, which is lovely actually in most ways because he's obviously been much more stiff and uncomfortable than I realised, a bit annoying to ride but so lovely to watch him move
although long term should I look for a more herbal sort of alternative - the vet doesn't seem worried about him just staying on it, I don't know, is it really much safer than bute? In general do the benefits of regular work outweigh the risks (he's on quite a tiny amount really, about half a sachet a day but dramatic difference)