How can taking vitamins for only 2 days support me for an entire month?

Cell Block contains Vitamins A and D. These vitamins are fat-soluble, which means that they stay in your system for a longer period of time than water-soluble vitamins, like Vitamin C. Therefore, you typically don’t need to continue to “top off the tank” with the fat-soluble vitamins like A, D, E, and K.