Used it a few years ago, during a course in West Virginia. Daily rucking in the mountains, and I mmanaged to stave off any joint soreness for the time I was there. I came off it when I got home, and my knees KILLED. My ATC at the time agreed with my suspicion that I had bruised the bones in both knees(tib/femur). Took about three months+ before I could run pain free.
But the cissus definitely helped at the time, just a bit too expensive for me to use regularly. Curcumin and piperine is cheaper, and does the job. I recommended it to a friend of my wife's who has RA. When she started taking it, she was able to get off the Humera and a couple other drugs she was taking.