My 19 yr old cat has been on Medi-Cal (Royal Canin) Mobility for over a year now. Prior to my diet choice I did bloodwork which indicated early renal, so picking the right arthritis medication became very important. Since being on the diet her renal function has not progressed and her activity has increased. She even jumps over the dog gate like a kitten again. I find there to be alot of misconceptions towards ingredients. I just know from my experience that my cat is doing awsome. Great hair coat, regular bowls and help her pain associated with arthritis.
If you do not want to change the diet. I was also considereing UBA VET Gold powder addative which includes green lipped muscle.
Hope info help