After 50 Years Studying How Light Controls the Human Body, I'm Asking You to Look at Your Lightbulbs. Especially If You're Over 60.

It is half past nine in the evening in my apartment in Boston.

The light over my reading chair is warm — the color of a candle flame, with no measurable amount of blue in it. My wife is in the next room. There is a book open on the arm of the chair, a glass of water on the side table, and a quietness in the room that, to a degree it is difficult to describe to anyone who has not noticed it, feels biologically right.

This is not because I have an unusual eye for interior design. It is because the bulb in the lamp on my desk is one I spent fifty years of my professional life trying to bring into existence.

My name is Martin Moore-Ede. I am a physician and a physiologist. For 23 years I was a professor at Harvard Medical School, where my colleagues and I helped identify a small structure in the human brain called the suprachiasmatic nucleus — the master clock that governs your sleep, your hormones, your immune defenses, and a great many things you have probably never thought about. I have published more than 160 scientific papers and ten books on this subject. The most recent is called The Light Doctor.

I have been writing publicly about lighting and human health for forty years, and lately on a newsletter called The Light Doctor on Substack. Most of my readers are over 60. The single most common message I receive from them is some version of the same sentence:

"Doctor, why is no one telling people this?"

I want to tell you what I have been telling them. And I want to tell you about the lightbulb that arrived in a small box on my doorstep last summer — the one currently lit on my reading lamp — because it represents the first time in my career that the science I have spent my life on has been put into a screw-in form your grandchildren could install in your home tomorrow afternoon.

I should also tell you, before we go any further, that a federal regulation scheduled for June 25, 2028 is about to remove this bulb — and every healthy bulb like it — from the American market. I will explain why, and what I think you should do about it, by the end of this article.

The Light We Were Born Under, And the Light We Built Instead

I grew up in postwar England in a house with a coal fireplace. The classic British arrangement, which warmed your front while ice grew on your back. We had no television. The windows were plain glass — no ultraviolet filtering, no infrared filtering, just glass — and my brother and I spent most of our daylight hours outdoors. In the evenings, our home was lit with incandescent bulbs and the orange flame of the fire, both of which emit copious amounts of red and infrared and almost no blue.

I did not know this then, of course. I knew only that the rooms felt warm. I learned the science later. The science is that for the first 10,000 generations of human existence, our ancestors lived under bright natural daylight during the day and very low levels of moonlight, starlight, or firelight at night. That was the lighting environment in which every system in our bodies evolved.

And then, in the space of about four generations — roughly the time between my grandparents and my own grandchildren — we replaced almost all of it.

Thomas Edison's incandescent bulb came first. It was, by accident, a reasonable approximation of candlelight: warm, low in blue, rich in infrared. The fluorescent tubes that followed were less benign. And the LED — the light-emitting diode that now sits in nearly every fixture in every home in America — was a final, decisive break with the spectrum we evolved under.

I want to explain why, because it matters, and because almost nobody in the lighting industry has been honest about it.

Modern LED bulbs are built on a foundation called a blue pump. The bulb starts with an LED chip that emits intense blue light at around 450 nanometers. A phosphor coating on top of the chip converts some of that blue into yellow, and your eye, looking at the mixture, perceives "white." This design was not chosen because it produces a healthy spectrum. It was chosen because it is the cheapest possible way to produce a lot of lumens per watt — which is, regrettably, the only metric the U.S. Department of Energy currently uses to evaluate a lightbulb.

The result is a light source that is biologically nothing like the sun. It has a sharp blue spike where the sun does not, an enormous dip in the cyan range where the sun is rich, and almost none of the violet, red, and infrared wavelengths that your body uses for purposes far beyond seeing.

And here is the part that, when I explain it to my readers, often makes them put down whatever they are holding: in the United States, residential lighting accounts for roughly six percent of household electricity use. The "energy savings" we have engineered our entire indoor lighting environment around — the savings that cost us our healthy spectrum — are a rounding error against the consumption of our heating systems, our appliances, and the artificial intelligence data centers that have come online in the last three years. We traded our biology for a fraction of a percentage point on the electric bill.

Forty Years of Watching the Evidence Come In

I have spent the last four decades watching, in the medical literature, what happens when a species evolved for ten thousand generations under one lighting regime is suddenly placed under a different one. The evidence has not been subtle.

Some of the cleanest data comes from comparisons between countries. Iceland, because it has no fossil fuels, did not begin building electric power plants until the late 1920s — a half-century after the United States and Britain. Its breast cancer rates climbed in tandem. Today, in regions of sub-Saharan Africa where rural communities still live without grid electricity, breast cancer occurs at roughly 20 cases per 100,000 women. In the well-lit cities of Western Europe and the eastern United States, the rate is between 120 and 140 per 100,000. Women who have been blind from an early age — and whose specialized retinal cells therefore receive no light signal at night, regardless of whether the lamps are on — develop breast cancer at significantly reduced rates.

None of these observations, taken alone, would prove anything. But the pattern repeats across cancers, across countries, and across the laboratory. In rodent studies, human breast cancer cells implanted on the skin of rats grow markedly faster when the lights are left on at night. Blood drawn from women sitting in darkness, with normal melatonin levels, suppresses the growth of those tumors when infused into the rats. Blood drawn from the same women under bright evening light does not.

And the population-scale studies, when they finally arrived, were larger than any of us expected.

I sat with this evidence for many years. I founded a company in 1983 called CIRCADIAN — it consults to half the Fortune 500 on the health of shift workers — and a research arm called the Circadian Light Research Center. I led the team that, in 2020, published the precise circadian potency spectrum of light: the wavelength sensitivity of the receptors at the back of your eye that decide whether your body believes it is day or night. The peak is at 480 nanometers, in the sky-blue range. Conventional LEDs land at 450nm — close enough to disrupt, far enough from the peak to be inefficient at the only thing the body actually uses blue light for.

The conclusion, after decades, was simple. We had built the wrong lights. And we had built them at exactly the time in human history when the lighting industry's customers were spending more of their lives indoors than at any prior point.

Why This Matters Most After You Turn 60

If you are reading this and you are over 60, I want you to understand something about your own eyes that almost no one is going to tell you.

The lens of the human eye is not a fixed object. It begins clear, in childhood, and yellows progressively across the decades — a slow, unstoppable, entirely normal process. By your seventies, your lens transmits roughly half as much light to the retina as it did when you were twenty. And the yellowing is not uniform. It blocks short wavelengths much more aggressively than long ones.

Which means: the 450nm blue spike that conventional LEDs emit — already a poor match for your circadian system at any age — is precisely the wavelength your aging eye blocks the most.

I published a chart of this in The Light Doctor last year. The numbers, drawn from the international standard CIE 203:2012, are these:

This is the part of the science that, when I show it to a room full of physicians, tends to produce a long silence. The lighting industry has not been making bulbs that fail to serve the elderly by accident. It has been making bulbs that serve the lumens-per-watt regulation, and the elderly have been collateral damage.

I would like that to stop.

What OIO Is, and Why It Took Forty Years to Build

The bulb sitting on my desk this evening was acquired by a lighting company called Korrus from a research firm called CIRCADIAN ZircLight in 2022. I founded that research firm. The patents Korrus licensed are, in part, mine.

I am telling you this for two reasons. The first is that I think you should know, before you read another sentence, that I have a relationship with the manufacturer of the bulb I am writing about. I am not a paid spokesman. I am the scientist whose laboratory developed the underlying technology, and I have an ongoing interest in seeing it reach the people who would benefit from it. You can decide how much weight to give my opinions accordingly.

The second reason is that the story of why this bulb did not exist until very recently is, in some ways, more important than the story of the bulb itself.

For most of the past decade, the version of this technology that my lab built was deployed only in commercial settings — Fortune 500 hospitals, around-the-clock manufacturing operations, military installations. The shift workers in those facilities slept better, made fewer errors, and reported fewer gastrointestinal disorders. The science worked. But the bulbs were specialty fixtures. They cost thousands of dollars to install. The grandparents I had been writing about could not buy one for their living room.

The engineering challenge of getting the same biology into a screw-in A19 bulb — the standard household lightbulb shape — took years. The version I had been waiting for arrived on my doorstep last summer. I screwed one into the lamp on my desk. I switched it on. A warm evening light bathed the room. I sat there for several minutes thinking, in a way that is difficult to describe, that this was a moment I had been imagining for forty years.

Here is what makes it different from every other LED bulb in your home:

The bulb comes with a small accessory called the OIO Loop — a simple lens you can hold up to the light to actually see the spectrum change as evening arrives. I find this object more useful than I expected. The biology is invisible to the naked eye. The Loop makes it visible. I have shown it to several physicians who became, on the spot, considerably more interested in the lighting in their own homes.

What I Do in My Own Home

People often ask me — at dinner parties, in the comments on my Substack — what they should actually do, in concrete terms, in their own homes. I will tell you what I do in mine. The protocol is short.

I am 80 years old. I sleep through the night. I do not need a sleep medication. The morning walk is the most reliable medical intervention I make in my own life, and the evening lights are a close second. Neither requires me to remember to do anything. The lights handle themselves.

An Evening Last Week, in My Apartment

My granddaughter visited last week. She is six years old, and she possesses, in the way only six-year-olds do, a complete and unselfconscious presence in the room she is in.

She came over for supper on a Tuesday. Afterwards, the three of us — my wife, my granddaughter, and I — sat in the living room, the OIO bulbs in their evening setting, the room the warm orange-amber color of a candle. My granddaughter was telling me, in considerable detail, about a disagreement she had had with another child at school. I was listening. Actually listening, in a way I am occasionally not — in a way that requires the kind of nervous-system calm that, in my experience, most modern living rooms are not conducive to.

I do not want to overdramatize what is, in the end, a lightbulb. But I will tell you what I noticed in that hour: I was not tense. My eyes were not tired. The room felt the way the rooms of my childhood felt — warm, low-key, quietly alive. The light was not asking anything of my body that my body did not want to give.

My wife went to bed at 10:15. I followed at 10:40. I slept until 6:23 in the morning, woke up, and went for my walk.

This is what I want for the people who read my newsletter. It is what I want for you.

The 2028 Problem — And Why I'm Telling You About It Now

I would normally close an article like this with a recommendation and let the reader decide on her own timeline. I am not going to do that today, because of a regulation that takes effect on June 25, 2028.

On that date, the U.S. Department of Energy will enforce a new minimum efficacy standard for general-service light bulbs: 125 lumens per watt. Every A19 bulb sold in America after that date will have to meet it.

I have been writing about this rule on my Substack for over a year. The regulation is well-intentioned and very poorly informed. The lumen — the unit being regulated — is a measurement of how bright a light appears to your eye, calculated almost entirely from the green and yellow wavelengths your eye perceives most brightly. The healthy parts of the spectrum — the violet, the deep red, the infrared, the carefully balanced blue — count as wasted watts in the calculation. A bulb that prioritizes any of them cannot meet the rule.

The regulation will, in effect, mandate the conventional blue-pump LED. It will eliminate from the American market every bulb that prioritizes biology over the lumens-per-watt formula — including, unless the rule is repealed before then, the bulb I have been describing in this article.

I have helped launch a petition to reverse this regulation. I encourage anyone reading this to support it. But I also want to be candid with you about what I think a person over 60 should do in the meantime, while the rule is still on the books and the bulbs are still being made.

I think you should put the right bulbs in your house now, while you can.

I think the cost is small, the installation is the work of an afternoon, and the downside of being wrong is that you have spent a few hundred dollars on light bulbs that screw into any standard lamp. I think the upside, based on the science I have been writing about for forty years, is significant.

What's Included With Your OIO Order

While Korrus continues to manufacture this bulb, every order includes the full system at 10% off for new customers:

The protocol I described earlier — morning walk, southeast-facing windows, zero-blue evening light, dark bedroom — is the protocol I follow in my own home. The single component of it most readers cannot easily replicate is the evening light. The bulb solves that.

If you take nothing else from this article, take this: just change the darn lightbulbs. Your body, especially after 60, will do most of the rest of the work for you.

Note: The 10% new customer discount is offered through this link directly from Korrus and may change without notice as the 2028 deadline approaches.

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