DL-LEU-DL-LEU DL-LEUCYL-DL-LEUCINE H-DL-LEU-DL-LEU-OH leucylleucine N-DL-leucyl-DL-leucine D-Leu-D-Leu-OH/D-Leu-L-Leu-OH/L-Leu-D-Leu-OH/L-Leu-L-Leu-OH,(1:1:1:1) 2-[(2-amino-4-methylpentanoyl)amino]-4-methylpentanoic acid 2-[(2-amino-4-methyl-pentanoyl)amino]-4-methyl-valeric acid