New Research: Sleep Helps the Brain Clear Toxins Linked to Alzheimer's Disease

On May 21, 2026, the journal Science published a research report by a team led by the neuroscientist Maiken Nedergaard of the University of Rochester in the United States. The report proposed that, after years of study, the team found that sleep is essential for necessary biological clearance. Sleep can clear many toxins produced by the brain during metabolism, and some of these toxins are precisely the culprits behind Alzheimer's disease.

Maiken Nedergaard said: “For decades, our understanding of sleep has focused mainly on memory and restoration. The view now taking shape is that sleep is also a highly ordered state of fluid transport that helps maintain brain health. Sleep has many functions, but I think clearing metabolites from the brain may be the most fundamental one.”

The study examined the role of a group of brain-regulating chemicals called neuromodulators, including serotonin and dopamine. It noted that although these substances mostly act independently while one is awake, affecting mood, attention, learning, and behavior, sleep “reorganizes their activity into coordinated brain rhythms.”

The various misfortunes and stressful events people encounter in life all have adverse effects on the brain. Most of us have had the experience that, no matter what sorrows and pressures we face, as long as we can sleep well, we wake up feeling much lighter. High-quality sleep not only restores physical strength but also eases mental suffering.

But how can one achieve high-quality sleep? In practice, I have found that insomnia is both a cause and a consequence of damage to the nervous system. Damage to the nervous system affects sleep, and insomnia in turn further damages the nervous system, gradually forming a vicious circle between the two. So treating insomnia is not as simple as just taking some calming and sleep-promoting drugs; the other diseases that trigger the insomnia must also be properly resolved.

The nervous system is the most powerful and complex system of the human body, and it is closely related to every tissue and organ throughout the body. Therefore the causes of nervous-system damage are very complex; merely identifying its cause is difficult, to say nothing of treating it.

For example, when I started university last year and attended military training, I met a friend at school who had suffered stubborn insomnia for many years and had sought treatment everywhere with little effect, and was very anxious as a result. At the time I noticed he had bad breath; I asked about his medication history and his other symptoms, and finally suspected that his insomnia might be caused by reflux esophagitis. I asked him whether he had acid reflux and heartburn, and he said he indeed did.

There is a TCM saying that “when the stomach is unharmonious, the sleep is restless.” The heartburn and restlessness caused by reflux esophagitis have a specific disease name in TCM called “coarse clamor” (zaocao). I suggested that he combine Wu Ji San (a classical TCM formula for peptic ulcer) with Jiaotong Wan (a classical TCM formula for coarse clamor); this regimen finally resolved the reflux and insomnia that had plagued him for years. As the insomnia was resolved, his anxiety also eased considerably.

My own father, on the other hand, has in recent years sunk into another kind of stubborn insomnia; his insomnia is probably caused by age-related degenerative changes such as cerebral atrophy and lacunar infarction. For his condition, a comprehensive approach is needed—unblocking the cerebral vessels, improving cerebral circulation, and calming the spirit to promote sleep. I later used a very large compound formula to treat him, based on several ancient formulas for treating the sequelae of stroke. My father at one point showed symptoms of early Alzheimer's disease; after taking the medicine his sleep improved a great deal, and as sleep quality improved, his condition in other respects improved as well.

My wife, meanwhile, has had insomnia over the past two years; her insomnia is probably related to my going away to study, together with her own work pressure and hereditary hypertension. I have thought of many ways for her, but the calming and sleep-promoting drugs I used mostly worked for only a few days. In the end, a medicinal pillow I made for her during this year's May Day holiday solved her problem. After using this pillow, her sleep quality improved dramatically, and she has now gone more than twenty days without any restless sleep.

So although scientists have concluded through research that sleep can clear many of the toxins the brain produces during metabolism, actually improving the sleep of insomniacs is by no means easy. Those who treat insomnia must be clinical physicians. And for a clinical physician to cure insomnia, there is an enormous amount of medical knowledge to learn. There is no universal panacea for insomnia; if a physician's knowledge is too narrow, it is very hard to diagnose the correct cause, let alone prescribe the right medicine.