Ergosterol, also known as ergostane, is a white or colorless, shiny flaky crystal or white crystalline powder. Ergosterol not only possesses unique physiological functions but is also widely utilized in drug development. As a crucial component of fungal cell membranes, ergosterol exhibits stable structure and strong specificity. Compared to glucosamine, it is more representative for biomass determination, allowing fungal biomass to be measured by detecting ergosterol content. The primary source of ergosterol is microbial fermentation synthesis, while recent studies have also reported its extraction from certain mycelia.