Sleep clears toxins from your brain via the glymphatic system.

The glymphatic system is a recently discovered brain-wide pathway that functions similarly to the lymphatic system in the rest of the body, facilitating the removal of metabolic waste and toxins from the central nervous system. Research shows that this system is primarily active during sleep, particularly deep non-REM sleep, when brain interstitial spaces expand, allowing cerebrospinal fluid to flow more freely and flush out waste products such as beta-amyloid and other neurotoxic molecules.

This process is believed to be critical for maintaining brain health and may help explain why sleep is biologically necessary. Multiple studies using animal models and human imaging have demonstrated that glymphatic clearance is significantly enhanced during natural sleep compared to wakefulness, supporting the claim that sleep clears toxins from the brain via this system.