NMN and Sleep: New Research Reveals a Surprising Brain Connection

Introduction

If you’ve noticed that sleep feels less restorative as you get older, that you wake more easily, dream less vividly, or simply don’t feel as refreshed in the morning, you’re not alone and you’re not imagining it.

REM sleep, the phase associated with dreaming, emotional processing, and memory consolidation, declines meaningfully with age. Researchers have known this for some time. What they haven’t fully understood is why, or what might be done about it.

A study published in May 2026 in the peer-reviewed journal iScience, led by researchers at Washington University School of Medicine, has shed new light on that question. And NMN is at the centre of the story.

What Is REM Sleep and Why Does It Matter?

Sleep comes in cycles, and not all sleep is equal. REM (rapid eye movement) sleep is the phase during which your brain is most active, processing memories, regulating emotions, and consolidating learning from the day before.

As we age, the amount of time we spend in REM sleep decreases. Research has linked lower REM sleep not just to feeling groggy, but to increased risks of cognitive decline and poorer long-term health outcomes. Understanding why REM sleep diminishes, and whether anything can support it, is an active and important area of ageing research.

What the Study Found

The research team, led by Professor Shin-ichiro Imai, one of the world’s leading scientists in NAD+ biology, set out to examine how NMN affects brain activity during sleep.

What they discovered was something they hadn’t anticipated.

A newly identified group of neurons

Using detailed electrical recordings in mice, the researchers identified a previously uncharacterised population of neurons in a brain region called the supramammillary nucleus (SuM). They named these “bursting slow-oscillation neurons” and found that they are most active precisely during REM sleep, firing at their highest rates during the dreaming phase.

These neurons appear to play a role in generating the rhythmic brain activity associated with REM sleep, with connections extending to the cortex and hippocampus, both critical for memory and cognition.

What happens to these neurons with age

In aged mice, the firing rate of these bursting SO neurons was significantly reduced compared to young mice. The rhythmic activity that characterises healthy REM sleep was disrupted. This decline in neuronal activity corresponds with the well-known reduction in REM sleep that accompanies ageing, and suggests a specific biological mechanism that may be contributing to it.

What NMN did

When aged mice were given NMN, the firing frequency of these neurons was restored to levels comparable to those seen in young mice. More importantly, REM sleep time increased in both young and aged mice following NMN administration. In aged mice specifically, the increase in REM sleep was the most pronounced effect observed.

The researchers also found that mice lacking Slc12a8, the protein that transports NMN into cells, showed impaired responses to NMN, reduced theta brainwave activity during REM sleep, and worse performance in a memory recognition test. This suggests that the brain’s ability to take up and utilise NMN directly influences sleep quality and cognitive function.

What This Means and What It Doesn’t

A few things worth being clear about before drawing any conclusions.

This is a mouse study. While rodent models are valuable tools for understanding biological mechanisms, the physiology of mouse sleep and human sleep differs in important ways. NMN was also administered by injection in this study, not taken orally as a supplement, which means the dosing and delivery differ from how people actually take NMN day-to-day.

What this study does provide is a credible and detailed biological mechanism: as NAD+ availability declines with age, specific sleep-regulating neurons in the brain lose their vitality. NMN, by restoring NAD+ levels, appears to restore their function, at least in this animal model.

It’s also worth noting that this research comes from the same laboratory that produced the landmark 2011 Cell Metabolism study on NMN and metabolic health, a group with a long and rigorous track record in this field.

Human trials specifically examining NMN’s effects on sleep quality are still limited, though broader NMN research in older adults has shown promising results in areas such as physical performance, muscle function, and energy metabolism. The sleep connection is a newer area, and one we expect to see more human research on in coming years.

Why We Think This Is Worth Knowing About

At MyVitality, we try to share research that deepens the picture rather than simply reinforcing what we already know.

Sleep is something we hear about constantly from our customers. The complaint isn’t usually “I can’t sleep at all.” It’s more often “I sleep, but I don’t feel rested” or “I used to be a deep sleeper and now I’m not.” That’s a REM sleep story as much as anything else, and this research offers a compelling biological explanation for why it happens.

We’re not in a position to say that NMN will improve your sleep. The human evidence isn’t there yet in sufficient volume to make that claim. What we can say is that the underlying biology is genuinely interesting, the research is rigorous, and if you’re already taking NMN for other reasons, the possibility that it may also be supporting sleep-related brain function is a meaningful addition to the conversation.

Our NMN is made here in New Zealand and third-party tested for purity and potency. If you have questions about whether it’s appropriate for your situation, we’d encourage you to talk with your GP.

Read the study: Cissé et al., iScience, May 2026 →

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