Gestonorone caproate, also known as norhydroxyprogesterone caproate, 17α-hydroxy-19-norprogesterone 17α-hexanoate, or 17α-hydroxy-19-norpregn-4-ene-3,20-dione 17α-hexanoate, is a synthetic norpregnane steroid and a derivative of progesterone. It is specifically a combined derivative of 17α-hydroxyprogesterone and 19-norprogesterone, or of gestronol (17α-hydroxy-19-norprogesterone), with a hexanoate (caproate) ester at the C17α position. Analogues and derivatives of gestonorone caproate include algestone acetophenide (dihydroxyprogesterone acetophenide), demegestone, nomegestrol acetate, norgestomet, and segesterone acetate, as well as 18-methylsegesterone acetate and the caproate esters chlormadinone caproate, hydroxyprogesterone caproate, medroxyprogesterone caproate, megestrol caproate, and methenmadinone caproate.