A while ago, I received some advertisement literature from Dr. David Williams. Things seemed to make sense to me in his articles so I saved his material in case I need it one day. I don't know what the current deal is. They sell a supplement called Joint Advantage and Dr. Williams' articles carried testimonies from many people with knee and Arthritis problems and fast relief after trying Joint Advantage for a short time. The supplement came with a 30 day money back guarantee.
I'm still relatively young and if I have joint pain one day, I may give Joint Advantage a try. And I will expect quick improvements and if not, I won't hesitate to return it for a refund.
I only heard about the supplement and have never tried it or know anyone that has tried it. But read the articles to see if it makes sense to you. Request the same articles as I received early last year. The booklet has the title "The Truth About Glucosamine and Chondroitin" (and it argues that G&C doesn't work well in practice).