Have a look at Hack Up Ltd and alex Gingell, he creates bespoke supplements for horses and they are fantastic, i have my ex eventer on one and 28yo with chronic arth in his hocks and he is on alex's stuff and doesnt need any bute. They are natural, very effective for pain relief, stiffness...
Have a look at Hack Up Ltd and Alex Gingell, he does Bespoke supplements which are unique to each horse, and he uses MS, GHCL etc and they work brilliantly. I used to use Coortavet HA but it was expensive and didnt seem to have the desired effect so i spoke Alex and got a bespoke one from and 18...