L-ergothioneine (Ergo) is a naturally occurring amino acid and is a thiol/thione derivative of histidine. Ergo is found in highest concentrations in mushrooms and bacteria, but other foods known to have lower levels of Ergo include king crab, beef, pork, lamb and chicken. Despite the presence of Ergo in foods humans consume, its biosynthesis has only been observed in certain bacteria and fungi. Humans produce a highly specific transport protein called OCTN1 for Ergo that makes it highly bioavailable and avidly retained, leading many to speculate about its potential importance to human health, because such specific transporters are rarely present for non-nutrient bioactive compounds. Learn about Ergo's applications for oxidative stress, prostate health and cognitive health in this white paper.