Trolox is a chromanol that is 6-hydroxychromane which is substituted by a carboxy group at position 2 and by methyl groups at positions 2, 5, 7, and 8. A cell-permeable, water-soluble analogue of vitamin E, it is used as a standard for measuring the antioxidant capacity of complex mixtures. It has a role as an antioxidant, a radical scavenger, a Wnt signalling inhibitor, a neuroprotective agent and a ferroptosis inhibitor. It is a chromanol, a member of phenols and a monocarboxylic acid.