Using Red Light to Improve Metabolism & the Harmful Effects of LEDs | Dr. Glen Jeffery

Red light exposure for just 3 minutes in the morning can improve color vision by 20% for up to 5 days by enhancing mitochondrial function. Meanwhile, excessive blue LED light exposure throughout the day may be damaging our mitochondria at levels comparable to asbestos exposure, affecting blood sugar

December 1, 2025 2h 14m
Huberman Lab

Key Takeaway

Red light exposure for just 3 minutes in the morning can improve color vision by 20% for up to 5 days by enhancing mitochondrial function. Meanwhile, excessive blue LED light exposure throughout the day may be damaging our mitochondria at levels comparable to asbestos exposure, affecting blood sugar regulation, liver health, and longevity.

Episode Overview

Dr. Glenn Jeffrey, a neuroscience professor at University College London, discusses how different wavelengths of light profoundly impact mitochondrial function and overall health. The conversation covers the benefits of red/near-infrared light for vision, blood sugar regulation, and cellular health, while warning about the potential dangers of excessive blue LED light exposure that dominates modern indoor environments.

Key Insights

Long-wavelength light penetrates deep into the body

Red and near-infrared light can pass completely through the human body, even through bone and clothing. This light scatters inside the body and affects mitochondria in all organs, not just at the surface where it's applied.

Water absorption is key to mitochondrial benefits

Long-wavelength light is absorbed by water surrounding mitochondria, changing water's viscosity and allowing the ATP-producing motors to spin faster. This explains why mitochondria themselves don't directly absorb red light, but still benefit dramatically from exposure.

Morning timing maximizes red light effectiveness

Red light therapy is most effective in the morning hours (sunrise to 11 AM) when mitochondria are naturally producing the most ATP. Effects are minimal in the afternoon when mitochondria are performing other cellular maintenance functions.

LED lighting may be causing systemic health problems

Modern LED lights contain high amounts of blue light without balancing red wavelengths, potentially causing mitochondrial dysfunction comparable to asbestos exposure. This may contribute to metabolic disorders, fatty liver, and reduced lifespan observed since 2010.

Early intervention is crucial for light therapy benefits

Red light therapy can slow aging and disease progression, but cannot reverse damage once disease has progressed significantly. Early intervention with appropriate light exposure is critical for maintaining mitochondrial health throughout life.

Notable Quotes

"This is an issue on the same level as asbestos. This is a public health issue and it's big."

— Dr. Glenn Jeffrey

"When we use LEDs, the light found in LEDs, when we use them, certainly when we use them on the retiny looking at mice, we can watch the mitochondria gently go downhill."

— Dr. Glenn Jeffrey

"Your body has never experienced such confined limited spectrum of light. Never experienced it before."

— Dr. Glenn Jeffrey

"Get a dog, right? Get a dog because you'll have to go out in daylight two or three times a day."

— Dr. Glenn Jeffrey

Action Items

  • 1
    Use red light therapy in the morning

    Expose eyes to 670+ nanometer red light for 3 minutes each morning (eyes can be closed). Use a simple red LED flashlight at comfortable distance for 5-day lasting vision and metabolic benefits.

  • 2
    Replace LED bulbs with incandescent or halogen

    Switch to halogen desk lamps or remaining incandescent bulbs to provide full-spectrum light that supports mitochondrial function, especially in windowless environments.

  • 3
    Maximize daily sunlight exposure

    Spend time outdoors daily to get balanced short and long-wavelength light. Even on cloudy days, natural light provides better spectral balance than artificial LED lighting.

  • 4
    Apply red light to specific body areas for targeted benefits

    For blood sugar regulation, apply red light to a small area of the back for systemic effects. For vision, focus on eye area. Effects take 1-2 hours locally, 24+ hours systemically.

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