I started using it when I began having difficulty walking up stairs and closing my left hand-- couldn't squeeze a tube of toothpaste--. I tend to be skeptical of nutritional supplements, so I've discontinued use a lot of times over the years. (It works well enough that after a while you don't seem to need it anymore...) I've discovered that within a month the stiffness and joint rigidity begins to return. I usually get six months supply at a time because it is sometimes difficult to locate a source of supply. (I originally found it at Costco, but haven't seen it there for maybe ten years.)