On 7 January, an international group of researchers reported that the hormone released into the circulation during physical exercise called irisin could prevent cognitive decline in Alzheimer’s disease (AD). In the study published in the journal Nature Medicine, scientists studied a gene called FNDC5, which is known to regulate the formation of irisin. Using tissue samples from US brain biobanks, researchers showed that irisin was present in the human brains of people with no cognitively impairments and that this level was reduced in the brains of people with late AD. Similar findings were described in AD experimental mouse models. Then, they genetically modified the mouse models to inactivate the FNDC5 gene and found that the mice had impairment in synaptic plasticity and memory. Conversely, overexpression of FNDC5/irisin restored brain function including memory defects in AD mouse models. In addition, scientists performed a protocol of daily swimming and looked at the effect of exercise on irisin and the brain of mouse models. They found that this exercise could prevent memory deficits and the reduction of FNDC5/irisin levels in the brain of mouse models. Together with these findings, researchers suggested that boosting irisin, either pharmacologically or through exercise, may constitute a potential strategy for therapeutic intervention in AD.