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

Episode 257 Dec 1, 2025 2h 14m 25 insights
Dr. Glen Jeffery, PhD, is a professor of neuroscience at University College London and a leading expert on how different colors (wavelengths) of light impact cellular, organ and overall health. He explains that long-wavelength light (red, near-infrared and infrared) can enter the body and brain to enhance mitochondrial function and thereby improve metabolism, eyesight, blood glucose regulation, mood, hormones and more. We also discuss how short-wavelength light from LED bulbs can impair mitochondrial health and why balanced, full-spectrum light is essential for health. Dr. Jeffery shares simple yet powerful ways to use natural and artificial light sources to enhance your metabolic function, eyesight and longevity. Sponsors AG1: https://drinkag1.com/huberman Wealthfront*: https://wealthfront.com/huberman Joovv: https://joovv.com/huberman Rorra: https://rorra.com/huberman Function: https://functionhealth.com/huberman Timestamps 00:00 Glen Jeffery 03:12 Light, Ultraviolet (UV), Visible & Infrared (IR) Light 06:25 Light's Impact on the Body & Light, Sunburn, Cataracts 09:55 UV Light, All-Cause Mortality, Skin Cancer 14:55
Actionable Insights

1. Leverage Long Wavelength Light

Utilize red, near-infrared, and infrared light to improve overall health, as these long wavelengths support mitochondrial function and can penetrate deep into the body.

2. Protect Mitochondria From LEDs

Employ long-wavelength light, such as red light, to protect against mitochondrial damage caused by excessive exposure to LED bulbs and screens, which contain detrimental short wavelengths.

3. Use Incandescent/Halogen Lighting

Replace or supplement LED indoor lighting with incandescent or halogen bulbs, especially in environments where you spend significant time, as they provide a full, balanced spectrum of light similar to solar light.

4. Enhance Vision With Light

Expose your eyes to long-wavelength light (e.g., 670 nanometers) for three minutes, once every five days, ideally in the morning, to improve color vision and overall visual function.

5. Red Light for Blood Glucose

Apply red light to a small area of skin (e.g., a 4x6 inch rectangle on the back) to significantly reduce post-meal blood glucose spikes by stimulating mitochondrial function.

6. Daily Sunlight Exposure

Get sunlight exposure both in your eyes and on your skin regularly, as it contains a balanced spectrum of light beneficial for health, but always avoid burning.

7. Prevent Sunburn

While seeking sunlight for its health benefits, always avoid sunburn, as it is linked to DNA mutations and skin cancers.

8. Shield From Excessive UV

Protect your skin and eyes from excessive UV and other short wavelengths to prevent mutations, sunburn, and conditions like cataracts.

9. Get Some UV Exposure

Ensure you get some UV light exposure, as it is necessary for processes like Vitamin D production.

10. Morning Light Therapy Optimal

For maximum benefit from long-wavelength light therapy, apply it in the morning, ideally from just before perceived sunrise until about 11 AM, as mitochondrial activity is highest then.

11. Comfortable Eye Light Intensity

When applying long-wavelength light to the eyes, use a dim to moderately bright intensity (e.g., around 1-8 milliwatts per centimeter squared) that feels comfortable, as high brightness is not necessary for effect.

12. Early Disease Light Intervention

For conditions like macular degeneration or other diseases, apply red light therapy early in the disease progression for the most effective impact on aging and disease mitigation.

13. Red Light for Mitochondrial Disease

For children with mitochondrial disease, consider introducing red light exposure (e.g., from specific light bulbs) in the home, as it theoretically helps and poses no harm.

14. Reduce Cellular Death

Utilize red light to reduce the pace of cell death, as it positively impacts mitochondria and their signaling for cell demise, contributing to longevity.

15. Systemic Light Benefits

Understand that long-wavelength light penetrates and scatters throughout the entire body, supporting mitochondria in all organs, so direct exposure to any part of the body can be beneficial.

16. Boost Brain Health With Light

Expose your head to certain long wavelengths of light, as they can pass through the skull into the brain to promote brain health.

17. Mitochondrial Community Response

Understand that mitochondria throughout the body act as a community, communicating and influencing each other, so local light exposure can have systemic benefits.

18. Utilize Plants for Infrared

Incorporate plants indoors and around buildings, especially on sun-exposed sides, as they reflect beneficial infrared light back into the environment, contributing to a healthier light spectrum.

19. Dim Incandescent for Longevity

Dim incandescent or halogen light bulbs to extend their lifespan and increase their output of beneficial infrared light, without significantly raising energy bills.

20. Take Lunch/Calls Outside

Maximize outdoor time by taking lunch breaks or phone calls outside to increase exposure to natural, full-spectrum light.

21. Wear Light Clothing Outdoors

When outdoors, wear light clothing to allow beneficial long-wavelength light to penetrate and scatter throughout your body.

22. Get A Dog For Outdoor Time

Consider getting a dog to ensure you go outside in daylight two or three times a day, increasing your consistent exposure to natural, full-spectrum light.

23. Increase Screen Distance (Kids)

For children, ensure they maintain an increased distance from screens and close-up work to help prevent the development of myopia.

24. Avoid Laser Light Therapy

Never use lasers for light therapy on your eyes or skin unless administered by a trained medical professional for a specific medical procedure, due to the risk of uneven energy distribution and tissue damage.

25. Avoid Infrared-Blocking Glass

Be aware that infrared-blocking glass in modern buildings can isolate you from beneficial long-wavelength light; advocate for or seek environments with non-infrared blocking windows.