Is a Single Light Bulb Really “Ruining Your Health”?
New Scientist August 2026 Cover: A Proposition Worth Taking Seriously—and Testing Against the Evidence
Lawrence Lin | Founder & CEO, Lighting Recipe Studio (LRS) | Founder & Chairman, Good Light Group Asia (GLGA)
Core Judgment: This is not an article to shrug off—and certainly not one to use as a tool for selling lights. The scientific question it raises is worth taking seriously; the causal answer it offers is still far from mature.
Over the past few days, a black-background cover has circulated rapidly across the international lighting and light-health communities on LinkedIn. Beside a hanging light bulb, it asks: “Why this light bulb is wrecking your health.” The article goes further, connecting modern LEDs, insulated glazing, the lack of red and near-infrared light, mitochondrial function, and a chain of purported causal links to diabetes, dementia, cancer, and cardiovascular disease.
This is not a story from a fringe publication. Its author, Graham Lawton, holds a degree in biochemistry from Imperial College London and a master’s degree in science communication. He has worked at New Scientist for many years and received the UK PPA’s Writer of the Year award in 2023. Precisely because of this, the cover has sparked more than simple sharing—it has triggered a serious, highly technical, and at times sharply contested debate over the evidence.
01 | The Real LinkedIn Debate Isn’t About Whether “Red Light Works”
As of the time of writing, a discussion post by German chronobiologist Manuel Spitschan had around 74 comments, while a post by renowned lighting designer Rogier van der Heide had around 70. Participants span chronobiology, vision science, lighting design, architecture and engineering, healthy buildings, and photobiomodulation. For a lighting cover story, this is more than ordinary social-media engagement—it has become a public, cross-disciplinary peer review.
Manuel Spitschan: There Is a Long Evidence Chain Between “Biologically Plausible” and “Harm to Populations”
Spitschan is Professor of Chronobiology and Health at the Technical University of Munich and also leads a research group at the Max Planck Institute. He acknowledges that red and near-infrared light can influence biological processes involving mitochondria, and that photobiomodulation is a legitimate field of research. But he points out that mechanistic experiments, small-scale interventions, associations with daylight exposure, and hypotheses about indoor light spectra represent different levels of evidence. They cannot simply be stitched together to conclude that “LEDs cause metabolic disease.”
His key reminder: Biological plausibility does not equal population-level harm. Correlation does not establish mechanism. And the effectiveness of a particular intervention does not mean that the absence of that intervention constitutes a “nutritional deficiency.”
Rogier van der Heide: Fear Is Not a Lighting Strategy
Rogier has more than 35 years of experience in lighting design. He has led global design teams at companies including Philips and Zumtobel and has received the IALD Radiance Award. His criticism focuses on the way the cover compresses a complex issue: the article discusses LEDs, glazing, daylight, infrared radiation, daily schedules, and architecture as an interconnected system, yet the cover reduces it to a single household light bulb—and, in doing so, creates a health scare.
He supports brighter days, gentler evenings, and better access to daylight. But he rejects slogans such as “ultra-processed light” or “95% of the spectrum is lost” when they are not clearly defined and are used in place of actual design strategies.
Kevin Houser: The Industry Has Even Gotten Part of Lighting History Wrong
Houser is a professor of lighting and human factors at Oregon State University and serves as a principal engineer at the Pacific Northwest National Laboratory. He adds an important industry perspective: many buildings transitioned from fluorescent lighting to LEDs, rather than directly from incandescent lighting to LEDs. Fluorescent lamps also do not produce the same rich infrared output associated with incandescent sources.
At the same time, temporal light modulation—often discussed as flicker—introduced by LED drivers may be a more immediate and measurable issue. A sensational “light bulb scare” headline can therefore distract from the health, comfort, and performance questions the industry actually needs to address.
Martin Moore-Ede: Don’t Let Dislike of the Headline Obscure the Potential Risks of Spectral Transition
There is also another side worth hearing. Martin Moore-Ede, head of the Circadian Light Research Center and a former professor at Harvard Medical School, argues that the cover has at least succeeded in drawing public attention to narrow-spectrum blue-pumped LEDs. He emphasizes that the issue is not only the absence of near-infrared light, but also the failure to remove inappropriate short-wavelength light at night.
It is worth noting that his post also promotes his own new book and his “healthy light diet” proposition. That does not automatically invalidate his views, but readers are entitled to understand the broader communication and commercial context surrounding them.
The emerging consensus on LinkedIn, therefore, is not that “LEDs are safe” or that “LEDs are harmful.”
A more accurate consensus is this:
Light is biologically active. Modern indoor light environments deserve renewed scrutiny. But any health claim must specify the spectrum, intensity, timing, duration, direction, site of exposure, and cumulative dose.
Campfires, candles, and incandescent lamps all contain relatively abundant long-wavelength components. But “contains” does not automatically mean “the dose is sufficient” or “the light has a clinically demonstrated effect.”
Image source: provided by the user / original article illustration.
02 | The Article Reveals Three Distinct “Light–Health” Pathways That Are Being Conflated
First: Light Enters Through the Eyes and Acts on the Circadian System
This is currently the relatively mature pathway. Sufficient daytime light exposure to the eyes helps synchronize the circadian system, while light at inappropriate times at night can affect sleep and circadian rhythms.
Relevant metrics include vertical illuminance at the eye, spectral power distribution, melanopic EDI, timing, and duration of exposure. This pathway is fundamentally different from asking how much near-infrared radiation is absorbed by the skin.
Second: Red / Near-Infrared Light Acts Directly on Tissue
This falls under the pathway of photobiomodulation (PBM). Research in this area typically uses specific wavelengths and clearly defined irradiance and energy doses to expose the skin or targeted tissue.
The appropriate measurement language is nm, mW/cm², J/cm², exposure area, and target location—not lux or CCT.
Applying results from therapeutic-dose experiments directly to ordinary indoor lighting is one of the article’s biggest logical leaps.
Third: The Overall Effects of Daylight and Outdoor Environments
Daylight simultaneously changes illuminance, spectrum, temporal dynamics, field of view, physical activity, air quality, temperature, and behavior.
If a daylight group performs better than an artificial-light group, that does not automatically prove that near-infrared light is the sole cause. These studies are highly valuable, but more refined experimental controls are needed to progressively separate the individual factors.
LRS Perspective: A “healthy lighting” question is not yet a verifiable engineering proposition unless we can first answer: Where does the light enter the human body? At what dose? At what time? And what biological target is it acting on?
03 | Put the Key Evidence Back Where It Belongs
The studies cited in the article are not without evidence. But the strength of that evidence is far from sufficient to support the kind of causal conclusions implied by the cover.
- 670 nm and blood glucose | 30 healthy participants received a 15-minute red-light intervention at approximately 36 J/cm². The incremental area under the postprandial two-hour blood glucose curve decreased by 27.7%, while the peak decreased by 7.5%. This was a clearly dosed, acute photobiomodulation (PBM) experiment—not a study of ordinary indoor lighting.
- Daylight and type 2 diabetes | 13 people with type 2 diabetes participated in a randomized crossover study comparing 4.5 days of daylight with 4.5 days of artificial light. One measure within a narrower blood-glucose range improved, but major outcomes such as mean interstitial glucose were not uniformly significant. More importantly, daylight represents an entire exposure environment and cannot be attributed to near-infrared light alone.
- Supplementing LEDs with broader-spectrum light and vision | A 2026 Scientific Reports study suggested that supplementing a conventional LED environment with broader-spectrum light may improve color-contrast performance. But the sample was very small, and the findings primarily concern visual performance. They cannot be extrapolated to risks of diabetes, cancer, or dementia.
- The overall clinical evidence for PBM | A 2025 umbrella review included 15 meta-analyses, 204 randomized trials, and more than 9,000 participants. Some indications showed positive signals, but the overall evidence was generally low to moderate quality, with substantial heterogeneity in treatment parameters.
What Can We Establish?
Most white-light LEDs produce little to no near-infrared output. That is a measurable spectral fact. Red and near-infrared light can produce biological effects at specific doses, and this is supported by genuine research evidence.
What Can’t We Establish Yet?
“Red-light deficiency” is not yet a recognized medical condition. There is no evidence establishing that the replacement of conventional lighting with LEDs is an important cause of diabetes, dementia, cancer, or cardiovascular disease. Nor is there a generally accepted healthy indoor near-infrared dose threshold.
Plant lighting has already become accustomed to discussing wavelengths beyond the visible spectrum. For human lighting to enter the same level of discussion, the first requirement is more rigorous definitions of exposure and more precise dose measurement.
Image source: provided by the user / original article illustration.
04 | Why China’s Lighting Industry and Academic Community Must Pay Attention
China has the world’s largest LED manufacturing base, supply chain, and application market. If long-wavelength light does prove to have meaningful long-term health value, the implications could be enormous. But if the evidence remains insufficient and is nevertheless packaged as “full-spectrum healthy lighting” or “NIR wellness lamps,” the potential for consumer misinformation—and subsequent industry backlash—could be equally significant.
Over the past two decades, we have optimized LEDs to be more efficient, more affordable, longer-lasting, and easier to control. None of these achievements is a mistake. But the industry’s evaluation framework still revolves primarily around luminous efficacy, illuminance, CCT, color rendering, glare, and cost.
Even as we move into “healthy lighting,” many projects still stop at melanopic EDI or a single “circadian mode” button.
The debate over near-infrared light now reminds us of something important:
We may not yet be measuring “light” completely.
- Traditional visual and circadian metrics primarily address the visible spectrum and ocular exposure.
- Tissue effects from red and near-infrared light require consideration of irradiance, energy dose, geometry, body location, and time-integrated exposure.
- “Full spectrum” cannot be defined simply by visual continuity, high CRI, or a color temperature close to daylight.
- Glazing, shading, interior materials, distance, and direction can all change the actual broad-spectrum exposure reaching the human body.
05 | What LRS and GLGA Are Building Is Not Another Slogan, but a New Evidence Infrastructure for Light
From traditional lighting and the transformation of the LED industry to the founding of LRS, I have watched the industry repeatedly compress complex questions into a single selling point.
But lasting intellectual credibility is rarely built by being the first to announce a conclusion. It is built by being the first to establish a common language, reliable measurement methods, and robust validation processes.
01 | Establish a “Two-Layer Light Exposure” Framework
Record ocular/circadian exposure separately from skin/tissue broad-spectrum exposure.
The former can use metrics such as melanopic EDI; the latter should extend to spectral irradiance and cumulative energy dose in the red and near-infrared ranges.
02 | Advance Broad-Spectrum Measurement Research Across 380–1700 nm
The next step for LRS should be to extend its existing capabilities in visible-light measurement, color quality, temporal light modulation, and HCL into a research-grade workflow covering the visible spectrum, IR-A, and portions of IR-B.
The goal is not to “prove” a product’s efficacy.
The first goal is to establish what light is actually present in the environment—and how much the human body may actually receive.
03 | Design Controlled Experiments Where Visible Light Is Equivalent but Near-Infrared Exposure Differs
Keep illuminance, CCT, color rendering, melanopic EDI, and temporal light modulation as consistent as possible while varying only the near-infrared dose.
Then separately examine visual, metabolic, sleep, and subjective comfort outcomes.
This is the kind of experimental design that could begin to identify the independent contribution of NIR.
04 | Build a Database Based on Real-World Chinese Environments
Offices, schools, hospitals, senior-care facilities, homes, industrial spaces, and transportation hubs should all be measured across the full day, with broad-spectrum measurements taken at multiple occupant positions—rather than measuring a single workplane illuminance value only at project acceptance.
05 | GLGA to Build a Cross-Disciplinary Community
Bring together researchers and practitioners from photobiology, chronobiology, endocrinology and metabolic medicine, ophthalmology, optical metrology, building science, lighting design, controls, and standards organizations to jointly establish research agendas, terminology, reporting templates, and conflict-of-interest disclosure rules.
The next step for healthy buildings is not to add another “healthy lighting” label to a luminaire.
It is to connect daylight, spectrum, time, space, and operational verification into one integrated system.
Image source: King’s College Hospital NHS Foundation Trust / provided by the user.
06 | Conclusion: The More Invisible the Light, the More Visible the Evidence Needs to Be
I do not believe we have enough evidence today to declare that “LEDs are destroying our health.” Nor do I believe the industry should retreat to the old defensive position that says, “As long as a product meets lighting standards, it has nothing to do with health” simply because a headline is exaggerated.
What this cover truly exposes is the knowledge boundary of the lighting industry.
We have become highly proficient at measuring the light that the human eye sees. Yet we are still not very good at describing the totality of light that the human body actually receives over the course of a day.
We are beginning to talk about health outcomes, but we still lack a shared language for dose, timing, pathways, and validation.
The worst thing the Chinese lighting industry could do is quickly manufacture another wave of “red-light mythology.”
The most valuable thing we could do is leverage our extensive supply chain, diverse application environments, and strong research capabilities to turn this question into a reproducible, comparable, and verifiable research program.
Call to Action
GLGA is open to working with Chinese and international organizations across photobiology, chronobiology, medicine, metrology, design, manufacturing, and standards to develop a research agenda for “indoor broad-spectrum light exposure and health.”
LRS is prepared to contribute the foundational work in measurement, data collection, and real-world validation.
We are not in a hurry to prove how miraculous red light might be.
First, let’s measure the light we cannot see.
What we should perhaps be most concerned about is not any particular light bulb.
It is that while the scientific boundaries remain unclear, we continue to use familiar metrics and pretend that we have already measured the whole of light.
Author Bio
Lawrence Lin is the Founder & CEO of Lighting Recipe Studio (LRS), Founder & Chairman of Good Light Group Asia (GLGA), Board Member of Good Light Group, and a WELL Light Concept Advisor for IWBI. He previously served as Global CEO of LEDVANCE.
His work focuses on translating research on light and health into lighting practices that are measurable, designable, deliverable, and verifiable.
Disclosure
LRS develops measurement tools for spectrum, color quality, temporal light modulation, and healthy lighting. As a result, LRS has a clear professional and commercial interest in the question of expanding the boundaries of light-environment measurement.
This article does not constitute medical advice, nor does it endorse the health benefits of any specific light source or near-infrared product.
The LinkedIn comments referenced in this article are translated excerpts or summaries of publicly available posts. Engagement figures are dynamic and may change over time.
Key References & Public Discussions
- New Scientist original article (Graham Lawton, August 10, 2026): https://www.newscientist.com/article/2582914-the-shock-revelation-that-light-bulbs-are-wrecking-your-metabolism/
- Public archive of the original article: https://archive.ph/lvNDq
- Manuel Spitschan’s LinkedIn discussion: https://www.linkedin.com/posts/spitschan_there-is-an-interesting-scientific-question-activity-7495302203025379328-oqzn
- Rogier van der Heide’s LinkedIn discussion: https://www.linkedin.com/posts/rogiervanderheide_new-scientist-i-think-we-need-to-talk-activity-7495395143349633024-2pel
- Martin Moore-Ede’s LinkedIn discussion: https://www.linkedin.com/posts/martin-moore-ede-80630a12_the-recent-new-scientist-magazine-cover-story-activity-7496213907687030787-EEmH
- Powner & Jeffery: 670 nm and blood glucose (Journal of Biophotonics, 2024): https://doi.org/10.1002/jbio.202300521
- Harmsen et al.: Natural daylight and type 2 diabetes (Cell Metabolism, 2026): https://doi.org/10.1016/j.cmet.2025.11.006
- Barrett & Jeffery: LEDs, broader-spectrum light, and visual performance (Scientific Reports, 2026): https://doi.org/10.1038/s41598-026-35389-6
- Umbrella review of PBM and multiple health outcomes (2025): https://doi.org/10.1186/s13643-025-02902-3
- Manuel Spitschan — official profile, Technical University of Munich (TUM): https://www.professoren.tum.de/en/spitschan-manuel
- Kevin Houser — official profile, Oregon State University: https://engineering.oregonstate.edu/people/kevin-houser
- Rogier van der Heide — official profile: https://www.rogiervanderheide.com/about-rogier-van-der-heide/
- Graham Lawton — 2023 PPA Writer of the Year: https://ppa.co.uk/ppa-awards-2023
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