Clinically proven to decrease oxidative stress and related immuno-suppression, a powerful antioxidant known as D-saccharic acid-1, 4-lactone (DSL) was discovered during the kombucha fermentation process that’s not found in black tea alone. Scientists suspect that DSL and the vitamin C present in kombucha are its main secrets in protecting against cell damage, inflammatory diseases, tumors and overall depression of the immune system. Also, we know the probiotics found in kombucha support the immune system.