A chemical (ester) that is derived from sitosterol (a sterol that is present in pine trees, and can be extracted from those trees). It can also be extracted from fibers (e.g., the hull or seed coat) of corn/maize (Zea mays) or soybeans (Glycine max L.). When sitostanol is ingested by humans in sufficient quantities, it causes their total serum cholesterol and their low-density lipoproteins (LDLP) to be lowered by approximately 10%, via inhibition (i.e., the sitostanol is absorbed by the gastrointestinal system instead of cholesterol).