Scientists from Tokyo Medical and Dental University have discovered that melatonin, a natural hormone known for helping us sleep, may also play an important role in keeping our memories sharp—especially as we age.
Their research, which focused on mice, suggests that melatonin and its breakdown products can improve memory and may help protect against memory loss and conditions like Alzheimer’s disease.
Melatonin is produced by the brain at night and helps regulate our sleep cycle. Once inside the body, melatonin is broken down into smaller molecules called metabolites. The researchers wanted to know if these metabolites had any effect on memory, especially since past studies had hinted that melatonin might support brain health.
To test their idea, the researchers used a simple memory task that works well in mice. Mice naturally spend more time exploring new objects than ones they’ve seen before.
But to recognize an object as “familiar,” they have to remember seeing it earlier. Mice with memory problems, such as those with age-related decline, behave as if all objects are new—even ones they’ve seen just a day before.
In the study, mice were first introduced to a few objects. One hour later, they were given either melatonin or one of its two key metabolites. The researchers tested the mice the next day to see if they remembered which objects were familiar.
They found that memory improved after treatment, and one of the metabolites—called AMK—was especially effective at boosting memory performance.
When they examined the mice’s brains, the researchers found that all three compounds collected in the hippocampus. This is the part of the brain that helps turn daily experiences into lasting memories.
They also found that if the conversion of melatonin into AMK was blocked, the memory-boosting effects disappeared. This shows that AMK is not just helpful—it’s necessary for the benefit.
Most importantly, AMK helped improve memory in both young and older mice. This is significant because memory problems usually become more common with age.
If future studies show that AMK has similar effects in humans, it could become a useful treatment for age-related memory loss and mild cognitive impairment (MCI). MCI is an early stage of memory decline that can sometimes lead to Alzheimer’s disease.
The research, led by Dr. Atsuhiko Hattori and published in the Journal of Pineal Research, offers a promising new direction in the search for ways to keep the brain healthy as we grow older.
While more research is needed to confirm the results in humans, the findings raise hope that one day a natural substance like AMK could help slow or even prevent memory problems in aging adults.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
For more health information, please see recent studies about Choline deficiency linked to Alzheimer’s disease, and what to eat (and avoid) for dementia prevention.
Copyright © 2025 Knowridge Science Report. All rights reserved.
