β-Amyloid (1-42), human, Ala(13C3,15N) TFA is a β-Amyloid (1-42), human marked with 13C and 15N. This unprocessed HFIP peptide comprises 42 amino acids and is a brain-permeable amyloid fragment, useful for researching Alzheimer's and Down syndrome. In monomer form, β-Amyloid (1-42), human provides antioxidant and neuroprotective effects. Upon HFIP monomerization and DMSO solvent preparation, it forms soluble oligomers (AβOs) at 4°C, which exhibit synaptotoxicity and neurotoxicity, while at 37°C it forms insoluble fibrils with lower neurotoxicity, involved in oxidative damage. Aβ42 oligomers interact with neuronal surface receptors such as PrPc, mGluR5, and NMDA receptor, activating signaling pathways that induce oxidative stress, calcium imbalance, synaptotoxicity, leading to neuronal dysfunction and death.