FNDC5 and Mental deterioration: By linking physical exercise to neuroprotection, anti-inflammatory activity, increased BDNF signaling, the prevention of dopamine neuron loss [169], antidepressant efficacy, and the potential to enhance reward processing and motivation in AD patients, irisin appears to possess many qualities that warrant further exploration as a therapeutic option in Alzheimer’s disease, both for controlling cognitive decline and managing NPSs.