I've not tried the HA version of Cortaflex neither their Kentucky supp (which looks good compared to some others and a good price too!) but i do keep my horses on, and swear by the normal Cortaflex- mine are in Medium work, have been on it for 2yrs after having previously been on a much more expensive vet garde one, and it really suits them and i've noticed a big difference in them since they've been on it.