# Using Red Light to Improve Metabolism & the Harmful Effects of LEDs | Dr. Glen Jeffery Source: https://www.youtube.com/watch?v=iT8W6kaD-RA Recap page: https://rapidrecap.app/video/iT8W6kaD-RA Generated: 2025-12-01T13:33:06.936+00:00 --- ## Quick Overview Long-wavelength light, such as red and near-infrared light, improves cellular metabolism by supporting mitochondrial function, potentially by altering the viscosity of the water surrounding them, and this effect is systemic, even penetrating through the skull to benefit the brain, contrasting sharply with the harmful effects of short-wavelength LED light which damages mitochondria. **Key Points:** - Dr. Glenn Jeffrey expresses extreme concern over short-wavelength light from LEDs, equating the public health issue to asbestos because it causes mitochondria to decline and become less responsive in real time. - Long-wavelength light (red, near-infrared) improves health by being absorbed by water within mitochondria, increasing the spin rate of the ATP-producing motor, and promoting the synthesis of more mitochondrial proteins. - Experiments showed that shining a small burst of red light on a limited area of the back systemically reduced the peak blood glucose response after a glucose tolerance test by just over 20% in humans. - Long-wavelength light penetrates deeply through the body, including through clothing and bone; measurements showed only a few percent of the light reflects off the skin, with the rest being absorbed and scattered internally. - Research on aging animals demonstrates that daily exposure to red light reduces the pace of cell death in the retina, preserving rod photoreceptors, a finding consistent with red light reducing the magnitude of cell death initiated by compromised mitochondria. - John Metrofanes' work showed that shining red light on the abdomen significantly reduced symptoms of Parkinson's disease in primate models, suggesting long-wavelength light mitigates degeneration where mitochondria are failing. - Short-wavelength (blue) light is highly energetic and damaging, causing sunburn (inflammation on the skin) and being blocked by the lens and cornea, leading to issues like snow blindness, whereas long-wavelength light is non-ionizing and safe for deep tissue penetration. **Context:** This discussion is an interview between Dr. Andrew Huberman, a professor of neurobiology and ophthalmology, and his guest, Dr. Glenn Jeffrey, a professor of neuroscience at University College London, focusing on the science-based applications of light, particularly red and near-infrared wavelengths, for improving cellular health and longevity. The conversation contrasts the benefits of long-wavelength light exposure with the dangers posed by ubiquitous short-wavelength light emitted by modern LED lighting and screens, exploring the mechanistic basis for these effects on cellular organelles like mitochondria. ## Detailed Analysis Dr. Jeffrey reveals that excessive exposure to short-wavelength light, common in LEDs, actively damages mitochondria, causing their membrane potentials to drop and their function to decline, a situation he deems a major public health concern. Conversely, long-wavelength light, such as red light, is highly beneficial; it passes through the skin and scatters throughout the body, supporting the health of mitochondria in deep tissues, including the brain, as it can pass right through the skull. The mechanism is hypothesized to involve the light interacting with the water surrounding mitochondria, increasing the viscosity of nano-water, which speeds up the ATP-producing motor, and also leading to the synthesis of more proteins associated with energy production pathways. This systemic effect was demonstrated in a human study where illuminating a small area on the back reduced the blood glucose spike by over 20% following a glucose tolerance test, indicating improved metabolic regulation systemically. Furthermore, long-wavelength light reduces the rate of cell death (apoptosis) initiated by distressed mitochondria, evidenced in studies showing preservation of rod photoreceptors in aging animals and the amelioration of Parkinson's disease symptoms in primate models when light is shined on the abdomen. The penetration capabilities of this light are significant; it passes through bone and clothing (six layers of t-shirt made no difference), though it is absorbed by deoxygenated blood, allowing visualization of vasculature. ### LED vs. Red Light Impact - Short-wavelength light damages mitochondria, causing them to 'gently go downhill' - Long-wavelength light improves function by supporting mitochondrial activity via interaction with surrounding water. ### Mitochondrial Mechanism - Long-wavelength light increases the spin rate of the ATP motor by altering water viscosity - It also influences the synthesis of more proteins involved in the electron transport chain, leading to long-term structural improvement. ### Systemic Metabolic Effects - Red light shone on a small patch of the back reduced the systemic blood glucose peak by over 20% during a glucose tolerance test in humans - This response is systemic, suggesting mitochondria act as a community. ### Light Penetration Capabilities - Long-wavelength light penetrates skin, bone, and clothing (even six layers of t-shirt) - It strongly scatters inside the body, reaching deep tissues and the brain through the skull. ### Neuroprotective and Vision Studies - Red light exposure reduced the pace of cell death in the retina's rod photoreceptors in aging animals - Red light shone on the abdomen significantly reduced symptoms in primate models of Parkinson's disease by reducing the magnitude of cell death. ### Safety and Ionization - Short-wavelength light (UV) is ionizing and causes cellular damage like sunburn - Long-wavelength light is non-ionizing and is considered safe for use in clinical settings, even shining through neonates' heads to monitor brain mitochondrial function post-stroke.