Dr. Glen Jeffery — Professor of neuroscience at University College London whose lab studies how long-wavelength (red, near-infrared, infrared) light improves mitochondrial function, vision, blood sugar regulation, and longevity. Formerly ran the eye bank at Moorfields Eye Hospital.
The gist
Andrew Huberman interviews UCL neuroscientist Glen Jeffery about how light of different wavelengths affects cellular health through mitochondria. Jeffery explains that long-wavelength red and infrared light penetrates deep into the body, is absorbed by the water surrounding mitochondria, and increases ATP production, while short-wavelength blue light from LEDs degrades mitochondrial function. They review experiments showing red light lowers blood glucose spikes, improves age-related color vision, and reduces cell death in the retina, with effects that last about five days and are strongest in the morning. Jeffery argues that modern LED lighting, infrared-blocking glass, and lack of outdoor exposure suppress human physiology, and that low-cost fixes like incandescent/halogen bulbs, sunlight, and plants can help. The episode closes with Jeffery's emotional account of red light helping a child with mitochondrial disease.
Big reveals
- Jeffery says excessive short-wavelength LED light is a public health issue 'on the same level as asbestos.'
- Most long-wavelength light hitting a naked body is absorbed and scatters inside the body, not reflected off the skin.
- Shining red light on a tiny 4x6 inch patch of the back cut the blood glucose spike by just over 20% systemically.
- Long-wavelength light passes through the skull into the brain; a UCL engineer shines it through neonates' heads to gauge mitochondrial survival.
- The vision-improvement effect is a binary 'switch' lasting exactly five days, conserved across flies, mice, and humans.
- Western European lifespan growth dented and began flattening around 2010, which some of Jeffery's colleagues link to LEDs.
- China's classroom red-light anti-myopia programs used lasers that burned spots in children's retinas.
- A child with mitochondrial disease given red light went from barely opening her eyes to walking to school; Jeffery 'went to the bathroom and sobbed.'
Things worth remembering
- Mitochondria themselves do not absorb red light; the water surrounding them does, which changes the water's viscosity and speeds the ATP motor.
- Red light makes mitochondria 'lay down more track' by synthesizing more of the proteins in the electron transport chain.
- Long-wavelength light passes through six layers of t-shirt and clothing of any color, including black.
- The retina has more mitochondria and the highest metabolic rate of any body part; Jeffery calls it 'the sports car.'
- The vision experiments used a small 670 nanometer flashlight for just 3 minutes, even working through closed eyelids.
- Effects are strongest in the morning before about 11am; a mitochondrion at 9am is functionally different from one at 4pm.
- Run-down flashlight batteries delivering just 1 milliwatt per cm squared still produced the vision effect.
- LED light, even 'warm' LEDs, has a big blue spike around 420-440nm and contains essentially no red light to counterbalance it.
- Mice raised under LED lighting develop fatty livers, smaller organs, abnormal sperm, and disrupted blood glucose on the same diet.
- All plant matter reflects infrared light, so plants and trees near windows can bounce therapeutic infrared back to people indoors.
Recommended in this episode
Books, products and media the guest or host genuinely endorsed here — with the buy link.
Affiliate link — we may earn a commission at no extra cost to you.
Protocols: An Operating Manual for the Human Body
Andrew Huberman
“I have a new book coming out. It's my very first book. It's entitled Protocols, an operating manual for the human body” — Andrew Huberman 02:12:20Find it on Amazon