While memory loss is widely known as the hallmark symptom of Alzheimer’s disease, new research points to a far more subtle and surprising early warning sign: the gradual loss of the ability to recognize familiar smells.

According to Professor Davangere Devanand of Columbia University, this decline in scent recognition could serve as one of the first red flags for cognitive decline.

The Connection Between Smell and Memory

Our sense of smell is closely tied to memory, and the areas of the brain responsible for processing scents are often among the earliest affected in the progression of Alzheimer’s. In a long-term study involving more than 1,000 participants, researchers used a simple scent identification test to look for early indicators of cognitive problems. Participants were asked to name 12 common odors—such as soap, smoke, rose, and leather.

Those who scored fewer than 8 correct answers were found to be at significantly greater risk of developing cognitive impairment over time.

As Reliable as High-Tech Scans

This basic smell test, especially when paired with a brief memory assessment, proved to be as accurate in predicting cognitive decline as more advanced techniques like MRI scans or in-depth neuropsychological evaluations. Even more importantly, it’s quick, non-invasive, inexpensive, and could be easily included in routine check-ups with a doctor.

Scents to Watch For

Some of the key odors used in the test include soap, gas, lilac, lemon, cherry, and menthol. If you find yourself repeatedly unable to recognize several of these—particularly one that was once familiar to you—it might be a good idea to consult a healthcare professional.

Your Shower Might Be Sending a Message

Sometimes, the first signs of serious health issues don’t come from forgetting names or dates—but from not being able to detect the scent of your shampoo. Your sense of smell could be offering an early clue that it’s time to check in on your cognitive health.