I've been taking Niagen for a couple of years now. I get mine from a company called Live Cell Research. I'm 64 and I feel pretty good these days and am very active. I'm a seasons pass holder at the Snowbird Ski resort here in Utah, I ride offroad motorcycles, play tennis 3 times a week, can walk 18 holes of golf like it's nothing so I'm going to continue taking it. But it's still hard to say exactly what the overall effect has been since I don't have another me to compare with. When people ask me how it's working I just say, ask me when I'm 100.