Synonyms: 2,5-Piperazinedione,3,6-bis(1H-imidazol-4-ylmethyl)- (9CI); 2,5-Piperazinedione,3,6-bis[imidazol-4(or 5)-ylmethyl]- (6CI,7CI); 2,5-Piperazinedione,3,6-bis[imidazol-4-ylmethyl]- (8CI); Cyclo(histidylhistidyl); Histidine, bimol.cyclic peptide