How a Simple Light Hack Can Boost Your Brain Health

What if a specific form and frequency of light therapy could help clean your brain and even protect against Alzheimer's disease? Well, breaking new 2025 research reveals how this might actually work and how you can take advantage of this new science today. Now, I'm going to get to that, I promise. But first, I need to arm you with some brain biology background about the brain's cleaning system, the glymphatic system. The glymphatic system is a set of channels in the brain that expand as blood vessels constrict. Imagine you have a blood vessel running through brain tissue, all bathed in cerebral spinal fluid. Well, when blood vessels constrict, generally during sleep, but not exclusively, as we'll find out, When they constrict and shrink in diameter, this creates space between the vessel and brain tissue, allowing for more cerebral spinal fluid to flow through and wash away, rinse out waste from the brain. I've reviewed this topic with a bit more detail in a prior video, so if you want more on glymphatic regulation, I'll refer you there. But a big question that I left as a cliffhanger to that prior video was how? How do you increase glymphatic flow and clearance of metabolic waste out of the brain? Okay, let there be light. 40 Hz blue light, to be more specific. 1 Hz equals 1 cycle per second, so 40 Hz just means 40 cycles or 40 flickers per second. Now, prior work has shown that 40 Hz light flickers can actually improve cognition in human Alzheimer's patients and in animal models. But how? Well, returning to glymphatics, this waste removal system is impaired in Alzheimer's disease, which means metabolic majunkus accumulates in the Alzheimer's brain, including amyloid oligomers, amyloid particles, and this can lead to a cascade of events precipitating cognitive decline, dementia, and progression of Alzheimer's disease. Now, there's one more nibble of neuronal knowledge I need to give you before we can get to the data. Lymphatic flow is regulated in part by water channels on brain support cells called astrocytes sitting around blood vessels in the brain. These water channels are called aquaporin-4, water pore 4. And to put it simply, more water flow through aquaporin-4 channels allows for better flow and more rinsing of metabolic debris out of the brain. Okay, on to the experimental results. What they did in the study is the researchers exposed mice, or a group of mice, a group of Alzheimer's mice, to 40 Hz blue light flickers for 1 hour per day for 2 weeks and then tested their cognition on validated cognitive tests like a Y Maze and Novel Object Recognition Test. The specifics of these tests aren't super important, but I named them in case you're interested and also provide more details in the newsletter associated with this video, which you can find in the video notes. Anyway, what they found, what the researchers found, is the blue light treatment improved memory performance on both tests. —closer to that of non-Alzheimer's control mice. And to chase the hypothesis that this improvement in cognition in the Alzheimer's mice exposed to blue light was related to enhanced glymphatic clearance—glymphatic clearance of waste from the brain—they injected a dye into the mice's brains that could be traced as it drains through the glymphatic system and out of the brain. So what you're looking at here—this is Figure 2C from the paper—is red dye in lymph nodes outside the brain. More red means more successful drainage and better glymphatic flow. And what you see here is less red in the middle panel, which represents the Alzheimer's mice without light treatment, as compared to control mice without Alzheimer's disease on the left. Then what you see on the right is Alzheimer's mice who were treated with blue light at 40 Hz for 1 hour per day for 2 weeks. And what you can see very clearly is more red more dye in these mice compared to the Alzheimer's mice that didn't get blue light treatment, suggesting more waste clearing, better glymphatic flow out of the brain. And in addition to that, they observed decreased levels of amyloid oligomers—this is Figure 2E—that are associated with Alzheimer's disease. So simply put, high level, the blue light 40 Hz treatment made the brain better at taking out the trash, taking out the metabolic waste. And as a nuanced note, they did indeed show in this study that blue light treatment, the 40 Hz blue light treatment, increased levels of this aquaporin-4 transporter that I mentioned earlier, which provides a mechanism by which the blue light flicker increased glymphatic flow. So I know that was a lot of jargon. Let's pause, collect, zoom out, and summarize. Glymphatic clearance and brain cleaning, they're impaired in Alzheimer's disease in human patients and animal models of Alzheimer's disease. But glymphatic flow can be enhanced by 40 Hz light flickers, which increases the expression of water channels, these aquaporin-4 channels that help with the glymphatic flow. And this system, this cascade causes improvements in amyloid levels, reduction in amyloid levels, and improved cognitive performance in at least animal models of Alzheimer's disease. Now, some people might have noticed I did emphasize "causes" because what they did next in this study was block different parts along the pathway I just described, like suppressing aquaporin-4 expression, and then exposing mice to the 40 Hz blue light flicker and seeing was there functional benefit. And at a high level, They showed that blocking parts of the pathway erased the benefits of the 40 Hz blue light. This is how researchers show causality in a mechanistic pathway. And for kicks and giggles, and if you really want a jargon bomb, brace for this. They found this system was dependent on something called the ventrolateral geniculate nucleus-intergeniculate leaflet nucleus reunions circuit. You don't really need to know that detail. Certainly you don't. But don't you feel smart now? I know I do. Anyway, I mentioned at the beginning of this video, if I didn't just lose you there, that you can take advantage of this science today. You can actually buy 40 Hz flicker light bulbs and lamps commercially. They're readily available. Now, after reading this paper, I just happened to do some internet snooping for my own selfish purposes, actually, and ended up deciding that Gamma Light Therapy provided the best all-around spectrum of options. And then I reached out to the company to get a discount code for me and for you. So you can use my discount code NICKNORWITZ, just my name, one word, by following the link in the video notes and get 15% off any product. And now an aside and a moment of transparency. For those of you who are just interested in how brand deals like this come together. I don't hear a lot of influencers talk about these things, so I want to. Here was the sequence of events. Last week, I got all excited reading about new science of the glymphatic system, glymphatic system regulation, which I covered in my prior video. I really hope you watched that. Anyway, my exchange with the first author, who incidentally works in the same department at Oxford as I got my PhD in, well, Conversation with me got me even more enthused. Thereafter, I decided to do more digging on the topic based on tips she gave me and came across the new research that I covered in this video just now. Now, these data, they're relevant to me personally because I'm at high genetic risk for Alzheimer's disease. I have two copies of the APOE4 allele, and sleep, which is when most glymphatic clearance occurs, is a weak point in my health routine. So the idea of enhancing glymphatic clearance is really meaningful to me personally. So then, after drafting notes for this video, composing the title, thumbnail, etc., on February 12th as I was flying back from The Cholesterol Code movie screener in Vegas, which was amazing by the way, you should totally see it, it's gonna come out in September, probably on Amazon or Netflix, not sure which, I spent some time on the flight snooping around on the internet for quality devices with reasonable price points and reached out to a couple companies. Gamma Light Therapy seemed to be the best all-around, and they agreed to offer us—me and you—a 15% discount. I'm not sure if this disclosure is helpful. Let me know in the comments. But I do want you to know—this is important to me—that 100% of the time, if I promote a product, it's genuinely because it's one that I value and would use myself or recommend to family members or friends or otherwise think has value, genuine value for you. So I hope this is received as it's intended, transparent and authentic. You can let me know in the comments. But in conclusion, what does this all mean for you? Well, while this research is still in its early stages, it shines a bright light on how something as simple as flickering light might help protect brain health by enhancing the glymphatic system's ability to clear out waste from the brain. And if future studies continue to confirm these findings in humans, we could be looking at a non-invasive way to support cognitive function and potentially reduce the risk of Alzheimer's disease. Of course, there's still a lot to illuminate. That's one of the great things about science. There always is. But one thing is clear. Our understanding of brain health is evolving rapidly, and discoveries like these could spark new breakthroughs in neurodegenerative disease prevention. Now, if you found this video enlightening, hit that like button. It helps get this information to more people who need it. And if I may ask, please smash that subscribe button and don't forget to turn on notifications so you don't miss more cutting-edge metabolic health science and tips. And finally, drop a comment below so we can keep the conversation glowing. Stay curious. I hope you found this video valuable.