Ganirelix acetate is a synthetic decapeptide with high antagonistic activity against naturally occurring gonadotropin-releasing hormone (GnRH). Ganirelix acetate is derived from native GnRH with substitutions of amino acids at positions 1, 2, 3, 6, 8, and 10 to form the following molecular formula of the peptide: N-acetyl-3-(2-napthyl)-D-alanyl-4-chloro-D-phenylalanyl-3-(3-pyridyl)-D-alanyl-L-seryl-L-tyrosyl-N 9 ,N 10 -diethyl- D-homoarginyl-L-leucyl-N 9 ,N 10 -diethyl-L-homoarginyl-L-prolyl-D-alanylamide acetate. The molecular weight for Ganirelix acetate is 1570.4 Dalton as an anhydrous free base.