I purchased this as a replacement to another antioxidant/immune booster I was using. I hate to admit it but I am not good at taking anything on a regular basis, so for long-term use I don't have any comment. But I do take this whenever I feel something and the next day I feel great again. I know it's not the best way to stay on top of my health but it works. I work in a very toxic nursing home environment and I have not had a cold or sniffle all winter. It's a keeper.