I've had knee stiffness and flexibility issues for the past two years (sports related). I turned to a natural supplement known as Isotonix OPC-3 through the recommendation of my cousin. It went for about $29.95, but the site offered cashback. The product has relieved a great deal of pain. I can flex my knees with less snapping, cracking and stiffness. The rest of my body has also benefitted. I can sit and walk with little to no signs of knee pain. This was the site that my cousin sent me to if you're interested in researching the product for yourself. http://www.marketamerica.com/masadoorian/