Widely considered as one of the most nutrient-dense foods on the planet, chaga mushroom has developed incredibly high concentrations of antioxidants in order to adapt to the harsh, arctic climates in which it grows. Found mainly on the bark of birch trees, chaga has been used as an immune tonic for thousands of years in its native Siberia and other regions of north Asia. By stimulating the production of immune boosting cytokines, chaga has been shown to help fight harmful bacteria and viruses – from minor colds to more serious illnesses. Several animal studies have shown chaga’s unique ability to lower cholesterol and balance blood sugar; but further human research on these claims is needed.