Neurodegenerative diseases, such as Alzheimer's disease, and Parkinson's disease, are characterized by progressive neuronal dysfunction and degeneration. These conditions often share pathological hallmarks such as protein misfolding, oxidative stress, neuroinflammation, and mitochondrial dysfunction. This review focuses on key pathological players like Tau and Amyloid-beta in Alzheimer's disease, highlighting their roles in microtubule destabilization, synaptic dysfunction, and neuronal death. The interplay between oxidative stress and these proteinopathies exacerbates neurodegeneration. Recent advances in therapeutic strategies are also explored, particularly the promise of biosimilars, cost-effective alternatives to biologics, targeting pathological hallmarks in neurodegenerative diseases. Biosimilars targeting Tau and Amyloid-beta in Alzheimer's disease, and alpha-synuclein in Parkinson's disease, hold the potential to improve treatment accessibility and reduce economic burdens. However, their development is still in its early stages. This review underscores the urgent need for innovative, affordable, and globally accessible therapeutic solutions to address the rising burden of neurodegenerative diseases.