We came across a viral post on X declaring a “terrifying link” between nose picking and Alzheimer’s disease. The claim suggests that damage to the nasal lining could allow germs to travel to the brain, triggering inflammation and potentially contributing to Alzheimer’s.
Alzheimer’s is a progressive form of dementia in which brain cells are gradually damaged, leading to the shrinkage of brain tissue and a decline in mental and cognitive function. While its exact cause remains unclear, it is thought to involve a mix of genetic and lifestyle factors.
According to the Institute of Mental Health’s Well-Being of the Singapore Elderly (WiSE) study in 2023, one in eleven Singaporeans aged 60 and above have dementia. With Singapore expected to become a superaged society in 2026, understanding how to prevent or delay cognitive decline is slowly becoming more important for individuals and families alike.
While the post stopped short of saying nose picking directly causes Alzheimer’s disease, the implication was unsettling and prompted us to dig deeper to determine whether there was any scientific basis to the claim.
Where does nose picking fit into this?
The suggestion that nose picking could be linked to Alzheimer’s disease appears to draw on broader research into the olfactory system (the network responsible for our sense of smell) and its relationship in neurodegenerative diseases.
Olfactory impairment has long been associated with neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Damage to the nasal lining or to the nerves involved in smell can occur through head trauma, viral infections or other injuries.
Autopsy studies have shown that neurofibrillary tangles (abnormal protein changes associated with Alzheimer’s), often appear first in brain regions involved in smell. This pattern is seen not only in people with Alzheimer’s but also in some younger individuals with no outward symptoms. These findings have led researchers to explore whether smell impairment could serve as an early indicator of cognitive decline.
With this hypothesis in mind, researchers have explored whether simple smell tests could function as non-invasive screening tools to identify people at elevated risk of cognitive decline. In this limited sense, the viral post touches on a legitimate area of research.
Infections and inflammation
While the X post itself cited no studies and offered no scientific evidence, our research suggests that the post’s implication of a more direct link between nose picking and Alzheimer’s can be traced to a specific 2022 study by researchers at Griffith University, Australia.
In that study, scientists found that when the nasal epithelium (the thin tissue lining the roof of the nasal cavity) was damaged, certain bacteria were able to travel along the olfactory nerve to the brain. Under these conditions, infections worsened and the bacteria triggered biological responses commonly associated with Alzheimer’s disease.
However, the study was conducted in mice, not humans. Although the researchers plan to investigate whether the same pathway exists in humans, this has not yet been demonstrated.
Moreover, the study focused on extreme trauma to the nasal cavity, including significant injury, prolonged infection, or deliberate exposure under controlled laboratory settings.
Although nose picking itself was not specifically studied, a media release quoted one of the researchers cautioning that damaging the nasal lining could allow more bacteria to enter the brain. Professor James St John, co-author of the study, hypothesised that nose picking could cause similar damage to the nasal lining, potentially enabling more pathogens to reach the brain and trigger a cascade of events associated with the development of Alzheimer’s disease.
Sniffing out the truth
A separate 2023 review by researchers at Western Sydney University explored whether damage to the nasal lining (including from behaviours like nose picking) could theoretically allow pathogens to reach the brain. While Alzheimer’s disease has traditionally been linked to the buildup of abnormal proteins, the review noted growing evidence that brain inflammation may also play a role and suggested the olfactory system as one possible pathway for infection.
The scientists conceded that a key limitation of this “infection hypothesis” is uncertainty about cause and effect. It remains unclear whether infections and inflammation actively contribute to Alzheimer’s development, or whether early, subtle changes linked to ageing and neurodegeneration weaken immune defences and make infections more likely in the first place.
What researchers broadly agree on is that inflammation in the brain is increasingly recognised as part of neurodegenerative disease. However, as acknowledged by Professor St John, occasional or gentle nose picking is unlikely to cause harm. Only repeated injury severe enough to damage nasal tissue would raise theoretical concerns, and even then, no human evidence links this to dementia.
There is currently no evidence that nose picking causes Alzheimer’s disease, and it is not a recognised risk factor. The known risks of the habit are more modest, such as increasing the chance of respiratory infections or causing local nasal injury over time. While some researchers hypothesise that frequent nose picking could, in theory, facilitate the movement of pathogens along smell-related pathways, this idea remains speculative and is largely based on animal or laboratory studies.
Overall, the viral post takes preliminary research and amplifies it into a frightening implication, making the claim partly false, and potentially misleading without proper context.
