Four Sigmatic is a brand of mushroom-based beverage blends. The company was born in Finland and now operates from the US. Their beverage blends are highly regarded in the biohacker community and are endorsed by influencers such as Tim Ferris, Ben Greenfield and Emily Schromm. What are functional mushrooms Mushrooms have been used for their nutritional and medicinal properties for centuries in several cultures (1, 2, 3). Thus, many mushrooms can be considered “functional”. Nutrients in mushrooms Mushrooms contain: carbohydrates, mainly polysaccharides (i.e. many sugars) which act as dietary fibre and prebiotics (i.e. food for gut bacteria), etc. (3, 4) amino acids (3, 4) polyunsaturated fatty acids (3) other molecules…