Parkinson’s disease (PD) is a progressive brain condition that affects movement. People with PD experience tremors, stiffness, and difficulty with balance and coordination.

New research suggests that people with PD might also have a particular smell. That said, it’s not something the average person is likely to notice.

This article reviews what we know about how Parkinson’s affects your body odor and sense of smell.

Everyone has a scent, whether or not they have Parkinson’s. Factors such as genes, food, and hormones determine your distinctive smell.

Health conditions can also influence how you smell. Among people with Parkinson’s, changes in scent are linked to an increased production of sebum, an oily substance secreted from the sebaceous glands in the skin.

However, it’s not a scent that most people would notice. Authors of a 2019 review note that a person with a heightened sense of smell detected the PD odor only recently.

Most people cannot detect Parkinson’s disease by smelling it. Although PD is linked to a specific scent, it’s not a smell the average person is likely to notice.

People with extreme sensitivity to smell, known as hyperosmia, are more likely to notice the PD smell.

Scent as a potential biomarker

Sebum may be a biomarker for PD. So, testing sebum could be a way of showing that someone has Parkinson’s.

A few studies are investigating the role of sebum in diagnosing PD. For example, the authors of a 2021 study compared the biochemical makeup of sebum from people with PD and a control group.

They reported significant differences between the two groups and suggested that evaluating sebum profiles might be a noninvasive way to test for PD.

Another 2022 study involved the development of a smelling device that uses artificial intelligence to detect the PD scent in a sebum sample. Researchers concluded that doctors might be able to use their system alongside other diagnostic tests to catch early stage PD.

Parkinson’s also causes hyposmia, which is a decreased sense of smell.

According to a 2019 review, people with hyposmia are nearly four times more likely to develop PD than people who do not have hyposmia.

Like the PD scent, hyposmia appears early in the progression of PD and may be a potential biomarker for the condition.

Hyposmia might make someone with PD less likely to notice their body smell, which could be an issue for family members and caregivers.

Keep reading to learn more about the role of smell in the diagnostic process.

Can dogs smell Parkinson’s disease?

A few recent studies say sniffer dogs might be helpful in diagnosing PD. For example, the authors of a 2022 study reported that trained sniffer dogs detected PD with high accuracy.

Can a smell test diagnose Parkinson’s disease?

A smell test evaluates your ability to smell. Currently, a smell test isn’t enough to diagnose PD. Though people with a reduced sense of smell are more likely to have PD, many do not develop the condition.

What is the gold standard test for Parkinson’s disease?

There are many diagnostic tests for PD. Your doctor will also ask about your symptoms and medical history and use the results from lab and genetic tests and imaging studies to reach a diagnosis.

Parkinson’s affects the production of sebum, an oil secreted on the surface of the skin, research states. This likely causes the slight difference in smell associated with Parkinson’s.

Recent research states that sebum from people with PD is different than sebum from people who do not have PD, making it a potential biomarker for the condition. Sebum might one day be used to test for PD.

If you or someone you know has PD and are experiencing a low sensitivity to smell or a change in odor, consult with a healthcare professional.