Ergosterol is widely used in the production of vitamin D2 through ultraviolet irradiation, making it essential in the pharmaceutical industry for dietary supplements aimed at addressing vitamin D deficiencies. In the field of mycology, it serves as a biomarker for identifying and studying fungal species, as it is a primary sterol found in fungal cell membranes. Additionally, ergosterol is utilized in research to develop antifungal medications, targeting its biosynthesis pathway to inhibit fungal growth. It also finds application in the food industry, particularly in the fortification of products like milk and cereals with vitamin D2 to enhance nutritional value.