Our Reishi 415 is made from 100%, log grown, certified organic, Reishi mushrooms (fruiting bodies). They are hot water extracted to pull out the beta-glucans. In the case of Reishi, it is also important to extract with alcohol to obtain the non-water soluble triterpenes. This is commonly called dual extraction. If other brands only list polysaccharide numbers, make sure to ask them for beta-glucan and starch numbers. This helps to determines product quality as there is a vast difference in quality between brands. Reishi History The Reishi mushroom has been revered in China for thousands of years and is utilized in Traditional Chinese Medicine as an immune system booster. Today it is widely cultivated using wood logs in shade houses. Scientific research for Reishi mushroom activity began in the 1970s in China and Japan. Scientists discovered highly active beta-glucans with the ability to potentiate innate immunity by activating immune cells. Also discovered were secondary metabolites called triterpenoids which were present in significant amounts and sets Reishi apart from all the other medicinal mushrooms.