Paroxypropione (INN) (brand names Frenantol, Frenormon, Hypophenon, Paroxon, Possipione, Profenone, numerous others; former developmental code name NSC-2834), also known as paroxypropiophenone (P.O.P.) or 4'-hydroxypropiophenone, is a synthetic, non-steroidal estrogen that has been used medically as an antigonadotropin in Spain and Italy.