These formulas contain either 150 or 300 mg of product, you just choose a quantity – up to 40% less with this Amazon deal today.  Our bodies evolved to require a molecule called nicotinamide adenine dinucleotide, or NAD and according to Lifespan: Why we Age – And Why We Don’t Have To, the loss of NAD as we age, and the resulting decline in sirtuin activity, is thought to be a primary reason our bodies develop diseases when we are old but not when we are young.