I have seen a huge difference in the knee that was bothering me. Also, I take it to ward off future problems, since it's supposed to help maintain healthy joints. When I told my doctor I was taking it, she said she recommends that people try it and see if it works for them. BTW, the first time I tried it, I quit--it was a three-times-a-day formulation, and I was always forgetting to take it in the middle of the day. I found a twice-a-day type at Costco, and as I said I've been very pleased with the results.