 The combination of microcrystalline estradiol benzoate and testosterone isobutyrate in aqueous suspension was introduced under the brand name Femandren M by 1953.Brand names of testosterone isobutyrate include Agovirin-Depot, Perandren M, Testocryst, and Virex-Cryst.It has also been marketed in combination with estradiol benzoate under the brand names Femandren M and Folivirin.