H4U reishi 45 capsules of H4U . Reishi mushroom is an adaptogen and general tonic. Its main benefit is its ability to regulate and tune the immune system to an optimal level. The reishi mushroom (Ganoderma lucidum), is an herbal mushroom known to have numerous health benefits. Hailed in ancient oriental medicine as the "mushroom of immortality" and "medicine of kings", it is renowned for stimulating the immune system. This supplement is capable of improving vitality and well-being. It is indicated to treat respiratory diseases because it increases the capacity of the immune system.