Also found in: Medical, Encyclopedia.


 (tə-kĭs′tə-rôl′, -rōl′)
An inactive compound, C28H44O, that is formed by irradiation of a precursor of vitamin D3 and can be converted back into that precursor.
References in periodicals archive ?
3] into biologically inactive metabolites, tachysterol and lumisterol.
3] to the inactive photoproducts lumisterol and tachysterol is an important step as it balances the cutaneous biosynthesis of vitamin [D.
Whereas irradiation in cyclohexane solution for one hour produces only about 5 per cent conversion of DHC to previtamin, the product is significantly contaminated with at least two by-products, lumisterol and tachysterol.