Sixteen complexes of copper(II) with six amino acids that are present in the b-amyloid peptide, which is associated with Alzheimer’s disease - aspartic acid, glutamic acid, methionine, glycine, serine and arginine -, two amino acids also found in the brain - cysteine and homocysteine -, as well as L-carnitine and acetyl-L-carnitine, which have been used as food supplement in patients with neurodegenerative diseases, were studied. Our aim was to determine the affinity of copper(II) with these amino acids, since aging causes an increase in brain concentrations of copper ions as well as in the level of all of these amino acids, as a consequence of peptide fragmentation. For this reason, we decided to do an in vitro study in similar conditions as the biological environment, using only deionized water as solvent. These compounds were characterized through the following techniques: elementary analysis (atomic absorption spectrometry and CHN), conductimetry, thermogravimetric analysis, electron paramagnetic resonance, electrochemical analysis, and infrared spectroscopy. It was possible to verify that, except for acetyl-L-carnitine, all amino acids behaved as bidentate ligands. They all form complexes with copper(II) easily. Aspartic acid, glutamic acid, serine, methionine, glycine and arginine coordinate through the oxygen atom of the a-carboxylate group and the nitrogen atom of the amine group. Cysteine and homocysteine coordinate through the sulfur atom and the nitrogen atom of the amine group, L-Carnitine coordinates through one oxygen atom of the carboxylate group and one oxygen atom of the alcohol group, and acetyl-L -carnitine coordinates through the oxygen atom of the carboxylate group.