I was using Synflex for humans and it worked very well. I was told by several medical people that the liquid joint supplements worked better because they were easier to absorb so I used those more often.

http://www.amazon.com/Synflex-1500-G...ywords=synflex

I used to be able to buy that Synflex inexpensively but then the price went way up. I switched to Liquid Health 5000 and it worked just as well. My old dog had arthritis pretty bad and I did see a difference.

http://www.amazon.com/Liquid-Health-...id+health+5000

The above links are just to show what those products look like. You can find much cheaper prices.

Try ebay and use google. Countryside Pets used to have good sales on the Liquid Health 5000 and I world buy it by the gallon for about $115 which lasted well over a year for one 50 pound dog.