Scientists have discovered that this seemingly harmless habit allows harmful pathogens, such as fungi, bacteria, and viruses, to enter the brain through the nose
14:55 ET, 25 Dec 2025Updated 14:55 ET, 25 Dec 2025
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Nose-picking introduces viruses, bacteria, and other contaminants into the nose(Image: Getty Images/Flickr RF)
Nose picking is often regarded as a bad habit, rather than a health risk. However, researchers are investigating a potential link between picking your nose and the risk of developing Alzheimer’s disease.
Researchers have discovered that this seemingly harmless habit allows harmful pathogens, such as fungi, bacteria, and viruses, to enter the brain through the nose. The study, published in Nature Scientific Reports, found that once the bacteria enter the brain, they stimulate the deposition of amyloid beta protein, potentially inducing the development of Alzheimer’s disease.
“Amyloid beta forms plaques that are thought to be responsible for many of the symptoms of AD, such as memory loss, language problems, and unpredictable behavior,” Medical News Today explained.
How does nose-picking potentially affect brain health?
The olfactory nerve in the nasal cavity directly connects to the brain. In this way, the bacteria can bypass the blood-brain barrier, which would normally prevent them from entering the brain.
A 2022 study conducted in mice found that Chlamydia pneumoniae, a bacterium that causes infections such as pneumonia, utilizes this route to reach the central nervous system.
“Other studies have shown that Chlamydia pneumoniae is present in Alzheimer’s plaques in humans. However, it is not known how the bacteria get there, and whether they cause AD pathologies or are just associated with it,” Prof. James St John, head of the Clem Jones Centre for Neurobiology and Stem Cell Research and supervising author of the study, told Medical News Today.
Prof. St. John added that individuals should avoid nose-picking and plucking hair from the nose. “If you damage the lining of the nose, you can increase how many bacteria can go up into your brain,” he said.
While this might not be the only cause of Alzheimer’s, it could be a contributing factor.
While research is still ongoing to establish a conclusive causal relationship between nose-picking and Alzheimer’s, there are many other reasons to avoid the unhygienic habit(Image: Getty Images/Flickr RF)
“We think there are potentially many microorganisms that may contribute to the onset of AD. We all have bacteria/viruses in our brains, but we don’t all get AD, so it might be a combination of microbes and genetics that lead to pathologies and symptoms,” said Prof. St John.
“We also think that it might be a long, slow process. So we don’t think that getting the bacteria in the brain means that you will get dementia next week. Instead, we think the bacteria set off a slow progression of pathologies that may take decades before resulting in symptoms,” he added.
Another study published in the journal Biomolecules found a similar link between nose-picking and Alzheimer’s disease.
What are the risks of nose-picking besides potential Alzheimer’s?
While research is still ongoing to establish a conclusive causal relationship between nose-picking and Alzheimer’s, there are many other reasons to avoid the unhygienic habit.
According to Medical News Today, these are the risks associated with picking your nose frequently:
- It introduces viruses, bacteria, and other contaminants into the nose.
- It spreads bacteria and viruses from the nose onto surfaces in the environment.
- It damages the tissues and structures inside the nose.
Scientists also reiterate the importance of hand hygiene as a preventative measure and recommend routine hygienic procedures, such as frequent hand washing and the use of hand sanitizers.