LED light bulbs are seriously affecting your health

New Scientist

A New Scientist investigation reveals an under-appreciated threat to public health: energy-efficient light bulbs. These alternatives to the old fashioned tungsten bulbs are systematically depriving the human body of wavelengths essential for cellular energy production.

New Scientist details how the shift to LEDs and infrared-filtering window glass has stripped indoor environments of red and near-infrared light, with cascading consequences for mitochondria, blood-sugar regulation, and the rising tide of chronic disease.

The concerns raised are not speculative. These concerns rest on clear biological mechanisms, experimental evidence, and the evolutionary reality that human physiology developed under full-spectrum sunlight.

For most of human history our bodies received abundant long-wavelength light—visible red (approximately 650–750 nanometres) and infrared extending to about 2,500 nanometres—from daylight, moonlight, fire, candles, oil lamps, and later from incandescent bulbs.

These wavelengths penetrate clothing and tissue deeply.

The mass roll out of modern energy-efficiency measures changed all that (and in many places, their use was made mandatory to help ‘save the plant’).

LEDs emit essentially no light beyond roughly 750 nanometres. Glass designed to block heat transfer filters out infrared. The result, according to researchers cited in the New Scientist piece, is the loss of approximately 95 per cent of the relevant spectrum for people who spend the bulk of their time indoors—up to 90 per cent of the day for many.

Below is a graph demonstrating the difference in wavelength and intensity between LED light and sunlight

Neuroscientist Glen Jeffery of University College London describes the change as sudden and consequential:

“Suddenly, without warning, boom, the long wavelengths go. And that’s a problem.”

The biological mechanism is now understood. Red and near-infrared light accelerate the electron transport chain inside mitochondria, increasing production of ATP, the cell’s primary energy currency. This process, termed photometabolism by former astrophysicist Bob Fosbury, is not incidental; life on Earth evolved for billions of years under sunlight rich in these wavelengths.

Each step in the chain requires an energy barrier of roughly 0.75 electron volts—precisely the energy delivered by a long-wavelength photon. When that input is removed, ATP generation slows. Blue-rich LED light and screen emissions compound the damage by actively inhibiting the same pathway. Diseased or stressed cells, already short of energy, suffer further.

The downstream effects track directly with the modern epidemics of metabolic and neurodegenerative disease. Slowed mitochondrial function impairs glucose utilisation, elevating blood sugar.

Jeffery’s controlled experiments demonstrated that a brief exposure to red light blunts the post-glucose blood-sugar spike. In real-world office settings illuminated solely by LEDs, occupants showed higher average blood sugar than colleagues given supplemental long-wavelength light from a dimmed incandescent source.

A separate study of people with type 2 diabetes found markedly better glycaemic control under natural daylight than under LED lighting in the same space. These findings are consistent with the observation that conditions linked to mitochondrial dysfunction—type 2 diabetes, obesity, dementia, Parkinson’s disease, certain cancers, and cardiovascular disease—have risen in parallel with the indoor lighting revolution.

Epidemiological signals reinforce the laboratory data. Analysis of nearly 88,000 people in their sixties showed that greater daylight exposure was associated with significantly lower risk of dementia over eight years.

Broader population studies using UV exposure as a proxy for overall sunlight found reduced mortality from cancer and cardiovascular disease among those with higher habitual outdoor light.

Red-light therapy, long used clinically for wound healing and other applications, appears in this light less as an exotic intervention and more as a partial restoration of a missing environmental input. As neurologist John Mitrofanis has noted, much of its benefit may simply correct a deficiency created by modern indoor environments.

Fosbury has likened the cumulative effect of red-light deprivation to “21st-century scurvy”—a deficiency disease that develops gradually, is not immediately obvious, and becomes severe only after prolonged exposure.

Unlike classical scurvy, the remedy is not a single vitamin but restoration of an entire spectral range that industrial design has systematically eliminated. The irony is acute: measures taken to save energy and reduce carbon emissions have inadvertently starved the metabolic machinery of the very organisms those measures were meant to protect.

The evidence already available is sufficient to establish cause for serious concern. It is not sufficient to define safe exposure thresholds, optimal spectra for indoor lighting, or the relative contribution of light deprivation versus diet, inactivity, and other factors.

Large-scale prospective studies, controlled trials of full-spectrum or red-enriched indoor lighting, and mechanistic work on mitochondrial responses across age groups and disease states are urgently needed.

There is now a persuasive scientifically-backed reason to look at reviewing our building codes, lighting standards, and public-health guidance must be revisited in light of photobiology rather than energy metrics alone. LED lighting is not healthy.

BBC’s ‘Headlight Glare’ Story and the Shocking Unseen LED Peril

As I have reported in my previous articles about the dangers of LED vehicle lights, we need to compel manufacturers to prioritise safety and quantify and disclose the spectral output of their products beyond the visible range.

Individuals can take interim steps—seeking natural daylight, using warm-spectrum or hybrid lighting where possible—but systemic solutions demand systematic science.

The New Scientist investigation has performed a public service by assembling the evidence and naming the problem.

The scientific community, regulators, and industry now have a clear obligation: treat long-wavelength light as a biological nutrient whose absence carries measurable cost, fund the research required to map that cost precisely, and act on the findings before another generation is raised under metabolically impoverished illumination.

The mitochondria of the human population are not an acceptable sacrifice to energy efficiency.

References

Lawton, G. (2026, August 10). The shock revelation that light bulbs are wrecking your metabolism. New Scientist. https://www.newscientist.com/article/2582914-the-shock-revelation-that-light-bulbs-are-wrecking-your-metabolism/

Powner, M. B., & Jeffery, G. (2024). Light stimulation of mitochondria reduces blood glucose levels. Journal of Biophotonics, 17(5), e202300521. https://doi.org/10.1002/jbio.202300521

Zheng, N., Wang, W., Li, B., et al. (2026). Associations between wearable-device-measured daytime and nighttime light exposures and dementia risk: A prospective cohort study. General Psychiatry. https://doi.org/10.1002/gps3.70039

Gordon, L. C., Martin, K. L., Torres, N., Benabid, A.-L., Mitrofanis, J., Stone, J., Moro, C., & Johnstone, D. M. (2023). Remote photobiomodulation targeted at the abdomen or legs provides effective neuroprotection against parkinsonian MPTP insult. European Journal of Neuroscience, 57(9), 1611–1624. https://doi.org/10.1111/ejn.15973

Weller, R., et al. (2026). Higher habitual UV exposure associated with lower mortality from cancer and cardiovascular disease [Preprint]. medRxiv. https://www.medrxiv.org/content/10.64898/2026.01.08.26343592v1

About the author: John O’Sullivan  is CEO and co-founder (with Dr Tim Ball among 45 scientists) of Principia Scientific International (PSI).  He is a seasoned science writer, retired teacher and legal analyst who assisted skeptic climatologist Dr Ball in defeating UN climate expert, Michael ‘hockey stick’ Mann in the multi-million-dollar ‘science trial of the century‘. From 2010 O’Sullivan led the original ‘Slayers’ group of scientists who compiled the book ‘Slaying the Sky Dragon: Death of the Greenhouse Gas Theory’ debunking alarmist lies about carbon dioxide plus their follow-up climate book. His most recent publication, ‘Slaying the Virus and Vaccine Dragon’ broadens PSI’s critiques of mainstream medical group think and junk science.