Nose-Picking May Have a Surprise Link With Alzheimer's, Study in Mice Suggests

Nose-Picking May Have a Surprise Link With Alzheimer's, Study in Mice Suggests Health 05 April 2026 By David Nield (EyeEm Mobile GmbH/Getty Images) Scientists think there's a tenuous but plausible hypothetical link between picking your nose and an increased risk of developing dementia. In cases where picking at your nose causes internal tissue damage, critical species of bacteria have a clearer path to the brain, which responds to their presence in ways that resemble signs of Alzheimer's disease. There are numerous caveats here, not the least of which is that the supporting research so far is in mice rather than humans. But the findings are definitely worth further investigation – and could improve our understanding of how Alzheimer's disease starts, which remains something of a mystery. In 2022, a team of researchers led by scientists from Griffith University in Australia published their study on tests with a bacterium called Chlamydia pneumoniae , which can infect humans and cause pneumonia . C. pneumoniae has also been discovered in the majority of human brains affected by late-onset dementia. The video below has a summary of the study's findings: frameborder="0″ allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen> It was demonstrated that in mice, the bacteria could travel up the olfactory nerve (joining the nasal cavity and the brain). What's more, when there was damage to the nasal epithelium (the thin tissue along the roof of the nasal cavity), nerve infections got worse. This led to the mouse brains depositing more of the amyloid-beta protein – a protein that is released in response to infections. Plaques (or clumps) of this protein are also found in significant concentrations in people with Alzheimer's disease . "We're the first to show that Chlamydia pneumoniae can go directly up the nose and into the brain where it can set off pathologies that look like Alzheimer's disease," said neuroscientist James St John from Griffith University in Australia, when the study was published. "We saw this happen in a mouse model, and the evidence is potentially scary for humans as well." The scientists were surprised by the speed at which C. pneumoniae took hold in the central nervous system of the mice, with infection happening within 24 to 72 hours. It's thought that bacteria and viruses see the nose as a quick route to the brain. While it's not certain that the effects will be the same in humans, or even that amyloid-beta plaques are a cause of Alzheimer's , it's nevertheless important to follow up promising leads in the fight to understand this common neurodegenerative condition. Illustration of amyloid-beta protein plaques, in orange. ( NIH/Flickr/PD ) "We need to do this study in humans and confirm whether the same pathway operates in the same way," said St John . "It's research that has been proposed by many people, but not ye