By Dr. Martin Moore-Ede, Publisher, The Light Doctor
If you want to know which wavelengths of light are most important for sustaining human health, look at the opsins. These light-sensitive proteins are a key component of the photopigments in the eye. Each detects specific wavelengths of light and triggers specific physiological responses.
Bound to a light-absorbing molecule called retinal, each opsin protein determines the specific wavelength of light that the photopigment will absorb. From opsin research, we know that light wavelengths at around 380 nm, 430 nm, and 480 nm are essential for good health. See image above.
The Missing Wavelengths That Matter
It is shocking how badly conventional blue pump LED lights are designed. Most of today’s LEDs fail to deliver sufficient light at the key wavelengths that the opsins in our eyes must detect to ensure our health.
The Opsins in the Human Eye
In the race to provide the cheapest brightness (i.e. the maximum lumens per watt), the LED industry has missed a fundamental truth. Human biology depends on the full daylight spectrum. An examination of the opsins in the human eye can tell us which are the key wavelengths.
Visual Opsins
First to be discovered were the visual opsins in cones (Opsin 1) and rods (Opsin 2) which we rely on to see the world around us. Color vision depends on three types of Opsin 1 which detect 420 nm violet-blue (Opsin 1 – Short wave), 534 nm green (Opsin 1 – Medium wave) and 560 nm yellow- orange (Opsin 1 Long wave)
Opsin 2 is Rhodopsin which is found in the rods which we use for night vision in the dark adapted eye.
Modern LEDs do a good job of stimulating these Visual Opsins 1 & 2. But light is not just about vision, it is also vital for health.
Non- Visual Opsins
Where conventional LEDs are grossly deficient, is in providing the specific light wavelengths detected by the non-visual opsins (3, 4 & 5) which are vitally important in regulating health1. As the chart shows, it is almost as though these LEDs were specifically designed not to provide healthy light!
Opsin 3: Encephalopsin (430 nm peak sensitivity)
Found in non-ipRGC retinal ganglion cells in the eye and in other tissues, Opsin 3 is essential in the refractory development of the eye and also plays a important role in energy and glucose homeostasis.
Opsin 4: Melanopsin (480 nm peak sensitivity)
In previous posts, and in my book THE LIGHT DOCTOR we have discussed Opsin 4which is Melanopsin – the photopigment in the ipRGCs (intrinsically photoreceptive retinal ganglion cells) in the retina of the eye. These detect the sky-blue light that is the key signal for synchronizing circadian clocks during the day, but which causes circadian disruption and ill-health if 440-495 nm wavelengths are detected at night. Conventional LEDs produce too little 480 nm blue during the day, and too much sky blue light at night.
Opsin 5: Neuropsin (380 nm peak sensitivity)
Opsin 5 has the most consistent structure across all species suggesting that it is most likely the most ancient opsin, and essential for fundamental biological functions. Like Opsin 3, Opsin 5 is found in non-ipRGC retinal ganglion cells. Opsin 5 is essential in the refractory development of the eye and also plays a important role in energy and glucose homeostasis. The huge growth in myopia in children has been linked to indoor lifestyles with a lack of deep violet exposure from daylight. (See my November 7th 2024 Substack post)
Far Red and Near-Infrared Light (825 nm peak sensitivity)
The other wavelengths critical for good health are in the far red and infrared part of the spectrum. These wavelengths do not have to be detected by opsins because they penetrate deeply into the human body and have a direct positive effect on mitochondrial energy production. The deepest penetration occurs in the Tissue Transparency Window with a peak at about 825 nm. (See my March 25th 2025 Substack post).
The Cost of Chasing Lumens Per Watt
The drive to maximize lumens per watt has resulted in cheap bright LEDs with a artificial distorted spectrum that are not fit for human use. They do not provide the light we need for good health.
Join Our Campaign against Regulations that promote unhealthy light
I urge you to join our campaign to challenge and replace regulations and standards that promote unhealthy lighting.
- The US Department of Energy (DOE) has been tightening the screws by introducing and enforcing minimum lumens per watt standards which only look at the visual brightness of a light and not its health-giving properties. In 2023, a 45 lumens per watt minimum standard was introduced which effectively banned all incandescent and halogen light bulbs. Then in 2028 DOE will tighten the screws even further with a 125 lumens per watt rule. As a result virtually all light bulbs will become narrow spectrum blue pump LEDs. See our petition and SIGN UP at https://circadianlight.org/doe-petition/
- The Design Lights Consortium (DLC), an independent body that sets standards for both lighting fixtures & lamps, has proposed new standards (SSL V6.0) which significantly raise lumens per watt minimums for fixtures (increased to 125 – 145 l/w) and E26 lamps (increased to 130 l/w). See our petition and SIGN UP at https://circadianlight.org/dlc-comments/
Conventional LED light is no substitute for daylight when it comes to health
As I discuss in my book THE LIGHT DOCTOR, modern narrow-spectrum blue-pump LED lighting, or legacy fluorescent lighting is not an adequate substitute for natural daylight. These lighting sources are deficient in providing key visible and near-infrared wavelengths that are essential for health. They also fail to remove the light wavelengths that are harmful at night.
To become smart about this critical subject, read my book THE LIGHT DOCTOR, available here.
Remember, the light we see is as important to our health as the food we eat, the water we drink, and the air we breathe.
Sources
I highly recommend this recent review article for those who want to learn more about the opsins and the problems with modern LED lighting:
Herschong L et al (2025) New dimensions of daylight and health: How opsin biology may inform lighting standards in the near future. Lighting Res Technology 57: 1-13 https://doi.org/10.1177/14771535251368368
Dr. Moore-Ede’s original substack post can be found here. Reprinted with permission.
All images courtesy of Dr. Moore-Ede.
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