As we get older the ability of our cells to produce energy declines. As energy declines, our ability to maintain muscle, and weight also decline. NAD, an essential part of energy production in the cells, declines to make it more difficult to produce the energy that the body needs.   Increasing the level of NAD in the body allows the cells to function more like they did when a person was younger. This can reverse some of the aspects related to the aging process. It works in two ways to fight age; it increases mitochondria activity and activates certain sirtuins that regulate life span.   NAD is essential in the functioning of the cell and biological processes. Studies are showing that if you maintain an optimal level of NAD, it can impact insulin existence, muscle wasting, inflammation, and aging. This may lead us to understand that aging can be reversed.