How to Help Your Brain Clean Itself (A Glymphatics Masterclass)
Every night, especially during deep sleep, your brain activates its glymphatic system to clear out waste. Here are evidence-based ways to improve that process.
Most organs in our body have a nutrient delivery system, blood vessels, and a waste removal system, called lymphatic vessels.
But my brain is apparently missing the waste disposal part!
(Maybe that’s why it’s packed with completely random animal facts.)
Jokes aside, all of our brains are, for the most part, missing the conventional lymphatic system.
The brain is so densely packed with blood vessels, neurons, and support cells that there simply isn’t room for the lymphatic vessels found throughout the rest of the body.
That raises an interesting paradox.
The brain is one of the most metabolically active organs in the body. It consumes enormous amounts of energy and generates plenty of metabolic waste.
So how is it supposed to get rid of that waste if it lacks the disposal system the rest of the body uses?
How is your brain supposed to clean itself?
Enter the “glymphatic system.”
The name comes from a combination of lymphatic—the waste removal system used elsewhere in the body—and glia, the support cells of the brain that play a central role in this process.
The glymphatic system is unique.
Rather than being a network of dedicated vessels like the lymphatic system, it’s a series of appearing and disappearing channels that become especially active while we sleep.
*Nuance note: Technically there are some meningeal lymphatics at the skull base, but for the most part the brain lacks a dominant conventional lymphatic system.
How Does the Glymphatic System Work?
When you’re asleep, your brain’s energy demands decrease.
As a result, it doesn’t require quite as much blood flow to deliver oxygen and nutrients.
The blood vessels are able to constrict slightly, creating more space around them.
That space forms glymphatic channels through which cerebrospinal fluid can be pumped, helping wash away debris that accumulated over the course of the day.
Glymphatic flow is essentially a shower for your brain.
And if your brain doesn’t get that shower, waste begins to accumulate.
Over time, impaired waste clearance is thought to contribute to metabolic dysfunction in the brain and play a role in cognitive decline.
What I’m really saying is that an effective glymphatic system is absolutely essential for maintaining brain health over the long haul.
That’s why today’s letter is devoted to explaining how to optimize glymphatic function.
Laying the Foundation: Stages of Sleep
I want to talk about deep sleep. But before we do that, we need to cover the different stages of sleep, so you have the proper frame of reference for what we’re about to discuss.
Stages of sleep:
Stage 1: Falling asleep.
Stage 2: Stable, foundational sleep.
Stage 3/4 (Deep Sleep): Physical restoration and brain cleanup.
REM Sleep: Mental restoration, learning, and emotional processing.
As simply as I can put it: deep sleep is the brain’s maintenance phase.
It’s when glymphatic clearance is at its highest, helping wash away metabolic waste that accumulates throughout the day. Deep sleep is also critical for physical recovery, immune function, and hormone regulation.
By contrast, REM sleep is the brain’s integration phase.
REM is incredibly important—you don’t want to lose REM sleep. During REM, the brain is highly active, which means glymphatic clearance is generally not as robust as it is during deep sleep. Instead, REM is when the brain processes emotions, strengthens learning, integrates memories, and supports creative problem-solving.
So, put simply, deep sleep helps clean and repair the brain, while REM sleep helps organize and optimize its performance.
You need both.
You don’t necessarily want to trade one for the other.
In general, the more of your total sleep time that is spent in deep sleep and REM sleep combined, the better.
Today we’ll talk about how to improve deep sleep and, thereby, glymphatic function.
But that’s not all.
We’ll then expand the discussion to cover additional tools: evidence-based supplements, peptides, sleep posture, and even some strange light and sound therapies supported by research published in top scientific journals.
Together, these interventions may further enhance glymphatic efficiency to clean and preserve your brain.
Get ready.
This one goes deep. (Get it?)
Today’s StayCurious Metabolism letter, a special request directly from a member of our community, is all about how to optimize the brain’s waste removal system and glymphatic clearance. We’ll dive into:
Evidence-based tools for improving deep sleep
Foundational lifestyle interventions
Accessible supplements and experimental peptides
The best sleeping position for glymphatic clearance
Light and sound therapies that enhance glymphatic function, drawing on research from some of the top scientific journals in the world.
If you’re passionate not only about optimizing your health, but also about exploring the complex biology within each and every one of us, now is as good a time as any to join the StayCurious Metabolism premium community and discover why members call it the best bang for their buck they’ve ever spent on their health journey.
