Alzheimer's disease (AD) is primarily indicated by the abnormal accumulation of amyloid-β (Aβ) and neurofibrillary tangles (NFTs) composed of phosphorylated tau proteins. Synaptic degradation and loss, which precede the emergence of amyloid plaques and NFTs, are closely related to cognitive impairments in patients. Soluble oligomeric Aβ initiates AD development, while tau protein facilitates later synaptic dysfunction during early AD stages. The review explores the mechanisms through which Aβ and tau contribute to synaptic disorientation and dysfunction. Aβ oligomers accumulate in synapses and induce synaptic degeneration through various mechanisms, including modulation of receptor tyrosine kinases, disruption of calcium balance, and activation of caspases and calcineurin. Hyperphosphorylated tau is highly present in the synapses. Synaptic impairments induced by Aβ are contingent upon the presence of tau, and soluble, hyperphosphorylated tau is strongly associated with cognitive deterioration in AD patients. Given the failure of Aβ-targeted therapeutics in treating AD, there has been increased attention on treatments targeting tau. Moreover, therapeutic approaches focusing on synaptic tau during the initial phases of AD may improve the disease's pathogenesis. Hyperphosphorylated tau, which can dissolve in water, interacts with receptors on cell surfaces, scaffold proteins, or molecules involved in intracellular signalling, thereby impairing synaptic function. This study looks forward to providing a current understanding of the involvement of oligomeric Aβ and soluble hyperphosphorylated tau in the initial development of AD and proposes a treatment approach to control AD.