Stigmasterol (also known as Wulzen anti-stiffness factor) is one of a group of plant sterols, or phytosterols, that include β-sitosterol, campesterol, ergosterol (provitamin D2), brassicasterol, delta-7-stigmasterol and delta-7-avenasterol, that are chemically similar to animal cholesterol. Phytosterols are insoluble in water but soluble in most organic solvents and contain one alcohol functional group