I have been a certified Nutrionist for five years now, and I have tried a lot of different herbs/vitamins. I have to admit that I find that Nature's Plus Source of Life is one of the best you will every try! You will feel that boost of energy, the amazing aleternes, and you'll find that when everyone around you has the seasonal cold/flu, you will be the only one not needing the box of tissure. They are a wounderful source to boost your immune system