I started taking these as a part of the Fast Track Detox several years ago, and never stopped taking them. After a recent relocation across the country and a break in my health regiment, I was sick for 6 weeks with two versions of the flu and bronchitis. I will NEVER go without these and my other vitamins again. I believe the health of my liver allows other nutrients to be absorbed properly. People always guess me to be 10 or more years younger than I am, and at 56, that is a great comment.