Abstract The misfolding and aggregation of amyloid-β (Aβ) peptides are histopathological features found in the brains of Alzheimer's disease (AD). To discover effective therapeutics for AD, numerous efforts have been made to control the aggregation of Aβ species and their interactions with other pathological factors, including metal ions. Metal ions, such as Cu(II) and Zn(II), can bind to Aβ peptides forming metal-bound Aβ (metal–Aβ) complexes and, subsequently, alter their aggregation pathways. In particular, redox-active metal ions bound to Aβ species can produce reactive oxygen species leading to oxidative stress. In this review, we briefly illustrate some experimental approaches for characterizing the coordination and aggregation properties of metal–Aβ complexes.