Joint supplements

Has anyone tried Cortaflex for their dogs joints??
I want to try a liquid glucosamine and Chrondoitin supplement but there are some many different ones on the market, i am a little sceptical as to which ones are effective.

Thank you

My Rottie and Bulldog are both on Cortaflex. My Rottie has has over £15,000 worth of vets treatments over the last 3 years on his legs (2 x tplo ops) and various other treatments so finding a good joint supplement was vital - Murphy has been on Cortaflex for about 18 months now and he hasnt been back to the vets about his legs once, he also wear a bio-flo collar (magnetic) which has also worked wonders for him but I know they dont work for all dog.

Everyone who I have suggested to to try Cortaflex have seen a good improvement in their dog.

My sis has good reports too, I'm just about to try Reah on it.