Yes we have lots of non-profit making organisations, usually run by previous suffers [out of the goodness of their hearts] that are excellent.
The MSM I am taking is with zinc [ Vit C is also necessary]it is made by NAF [Natural Animal Feeds]Monmouth.[www.naf-uk.com] It is packaged with instructions for feeding horses.It's much cheaper that way 300grams was £14.0 I don't know what that is in $s.It should last quite a long time at 1 teaspoon x 2 a day. I would go to an animal feed shop and enquire, lots of people use it for old stiff horses to keep them running or after a tough competion. It's already helped my stiff back and shoulder after only 10 days.Good luck. Love and Light Deotima.