"AKA (25R)26-hydroxycholesterol; Named with systematic nomenclature, where hydroxylation at the terminal side chain of cholesterol is on C-26 leading to 26-hydroxycholesterol (26-HC) which may have 25R or 25S stereochemistry [26]. Unless stated otherwise 25R stereochemistry is assumed. In much of the literature (25R)26-HC is referred to 27-hydroxycholesterol (27-HC), presumably the 25R isomer." [PMID:22366074]