Healthy Light With LEDs? Dr. Alexander Wunsch’s Stark Warning At Biohacker Summit

At the Biohacker Summit in Helsinki, Dr. Alexander Wunsch and Matt Maruca argued that modern LED lighting had become a biologically impoverished substitute for daylight, urging people to seek sun by day, darkness by night, and stronger protection from the blue-heavy glare of modern life.

A Case Against The Light We Now Take For Granted

In a presentation titled Healthy Light with LEDs - No Chance?, delivered on Tuesday, 2 July 2024 at the Biohacker Summit in Helsinki, Finland, Dr. Alexander Wunsch and Matt Maruca mounted a forceful challenge to one of modern life’s quiet assumptions: that light is light, and that efficiency is an uncomplicated good.

Wunsch, an integrative physician and light therapist long known for his work on the biological effects of light, framed the issue in terms both clinical and civilisational. For more than a decade, he said, public policy had favoured energy efficiency while paying too little attention to what was lost when the incandescent bulb disappeared from ordinary life.

“It’s about sixteen years ago that the EU decided to ban the only light source with a natural spectral distribution, which was the incandescent lamp, due to energy efficiency reasons,” he told the audience. The trade-off, in his telling, was profound: “They sacrificed health for the sake of energy efficiency.”

Why Daylight Was The Standard

At the heart of Wunsch’s argument was a simple but unsettling claim. Human biology evolved under daylight, not under the spectral spikes of LEDs, screens and sealed indoor environments.

Modern humans, he noted, now spend more than 95% of their lives indoors, receiving too little bright natural light in the day and too much artificial light at night. That mismatch, he argued, was no mere inconvenience. It was a disruption to the body’s deepest rhythms.

One large study, cited during the talk, sharpened the point. “Avoiding light at night and seeking light during the day may be a simple and effective non-pharmaceutical means of broadly improving mental health,” Wunsch said, calling attention to evidence that daytime light and nighttime darkness each exerted independent effects on wellbeing.

Maruca, founder and chief executive of Raw Optics, stepped in at intervals as a moderator and translator of sorts, bridging scientific complexity with practical concerns. The finding, he said, was among the most significant in the field because it showed that daylight exposure could not simply cancel out the damage of nighttime illumination. Both mattered.

The Missing Ingredient In LED Light

The presentation’s central scientific complaint concerned spectrum. Daylight, Wunsch said, was not just bright. It was balanced.

That balance included not only visible wavelengths but also a large amount of near-infrared light, a part of the spectrum largely absent from standard LED lighting. This omission, he argued, had consequences for ocular health, mitochondrial function and cellular repair.

“Near-infrared is so important for maintaining our ocular health that we should always take care that we have enough near-infrared present in the environmental light,” he said.

By contrast, LEDs were described as delivering an excess of high-energy visible light, especially in the blue range, while withholding the longer wavelengths associated with recovery and regeneration. Wunsch linked the short wavelengths to increased formation of reactive oxygen species, which in excess can damage cells, while the longer wavelengths were associated with melatonin production, energy metabolism and antioxidant effects.

His conclusion was blunt: “Changing a natural spectral distribution leads to problems.”

The Window, The Screen, And The False Comfort Of Indoors

If LEDs were the obvious culprit, Wunsch warned that the problem did not end there. Windows, often treated as substitutes for outdoor exposure, came under particular scrutiny.

Modern glass, he said, could strip away beneficial near-infrared while still allowing substantial UVA radiation to pass through. The result was a deceptive kind of exposure: enough shortwave stress to age tissues, not enough of the balancing wavelengths that accompany unfiltered daylight outdoors.

The same logic applied to screens. Their spectra, he said, were marked by sharp LED peaks and an almost total absence of near-infrared. For those spending their days in front of laptops and phones, that meant long hours under a form of illumination unlike anything human physiology had evolved to expect.

The argument was not merely theoretical. Wunsch pointed to evidence linking shorter wavelengths to retinal stress, cataract formation, dry eye syndrome, visual fatigue and skin ageing. Longer blue wavelengths, particularly those affecting circadian and hormonal systems, were tied to stress hormones, sleep disruption and downstream chronic disease.

A Lighting Scheme For Day And Night

What emerged from the session was less a rejection of technology than a plea for discrimination. Not all light should be treated as equal, and not all times of day should be lit the same way.

Wunsch urged the audience to think in terms of two distinct lighting schemes: one for daytime, one for nighttime. During the day, the goal was to maximise outdoor daylight exposure wherever possible. Indoors, if artificial lighting was unavoidable, he suggested choosing warmer LEDs with better colour rendering and avoiding the most energy-efficient models, which he suggested often had the poorest spectral quality.

At night, the priority shifted decisively toward minimising light, especially blue-rich light that can disrupt hormones and circadian timing.

In the northern latitudes, where Finland’s extremes of winter darkness and summer brightness create their own challenges, Wunsch offered a cautious middle path: short, deliberate exposures to high colour temperature light when needed, ideally balanced with near-infrared, but without tipping into chronic overstimulation.

The Contested Case For Blue Light Glasses

There was, unsurprisingly, a practical question hanging over the room: what could ordinary people do when they could not redesign offices, homes or public spaces?

Here Maruca’s presence became more than incidental. His company manufactures blue light protection eyewear, and the talk acknowledged this commercial intersection. Yet Wunsch defended the utility of such glasses, particularly against claims that they were ineffective.

The distinction, he said, lay in the lens itself. Clear lenses marketed as protective offered very little reduction in harmful wavelengths. Tinted lenses, by contrast, could make a meaningful difference.

“With a true colored blue light protection, you get 80% to 99% reduction and only ten to 15% reduction maximally from clear lenses, which claim to be protective,” he said.

It was one of the presentation’s most practical takeaways: if blue light blocking glasses were to be used, colour mattered, and marketing language alone was not enough.

A Modern Convenience With An Ancient Cost

For all its technical language, the presentation returned again and again to a deeply human theme. The crisis Wunsch described was not only one of bulbs, wavelengths or product standards. It was a crisis of estrangement from natural conditions.

People now live behind glass, under synthetic light, seated before luminous rectangles, spending their brightest hours indoors and extending daylight deep into the night. The body, he implied, has not changed nearly fast enough to meet this environment.

The most effective intervention, therefore, was also the oldest: more real daylight, more darkness after dusk, and greater respect for the rhythms that once came free with sunrise and sunset.

At the Biohacker Summit, amidst the usual language of optimisation and performance, Wunsch’s message carried a quieter severity. The healthiest light, he suggested, had never been engineered. It had been there all along.

Frequently asked questions

What is wrong with LED lighting?

Dr. Alexander Wunsch argued the problem is spectrum. Daylight is not just bright but balanced, including a large amount of near-infrared light that is largely absent from standard LEDs. That omission, he said, has consequences for ocular health, mitochondrial function and cellular repair.

How much time do people spend indoors?

Wunsch noted that modern humans now spend more than 95% of their lives indoors, receiving too little bright natural light during the day and too much artificial light at night. He treated that mismatch as a biological disruption rather than an inconvenience.

Do windows solve the problem?

Not according to Wunsch. Modern glass, he said, can strip away beneficial near-infrared while still admitting substantial amounts of other wavelengths, which makes the indoor daylight many people rely on a poor substitute for going outside.

About the event

This recap is part of the Biohacker Summit 2024 Helsinki series, recorded in Helsinki on 2 and 3 July 2024. Read the summary of the whole event or join the next edition, HOLOLIFE Summit 2026 Amsterdam, on 14 and 15 November 2026.