Red Light Therapy Wavelengths: A Chart from 460 to 1072 nm
Red light therapy uses two bands of light: visible red at about 620 to 700 nm and invisible near-infrared at about 800 to 1,100 nm. Within those bands a handful of wavelengths turn up again and again in trials and on devices: 630, 660, 670, 810, 830, 850 and, more recently, 1060 to 1072 nm. Blue (460 to 480 nm) and amber (590 nm) sit outside the red band but are fitted to many masks and panels. There is no single best wavelength. The main thing a wavelength decides is how far the light travels before it is absorbed: red works in the skin, near-infrared carries on into the tissue beneath it. The chart below lists each wavelength from 460 to 1072 nm, how deep it goes, and what it has been tested for in people, with the study behind every entry.
What wavelengths does red light therapy use?
Red at about 620 to 700 nm and near-infrared at about 800 to 1,100 nm. These fall inside the "optical window", the range where blood and water absorb the least and light travels furthest through tissue.
One review of the field puts the useful ranges at 600 to 700 nm for red and 770 to 1,200 nm for near-infrared. AIMS Biophysics, 2017 Below about 600 nm, haemoglobin in blood soaks up most of the light near the surface. Above about 1,200 to 1,300 nm, water does the same. In between, the light that matters is thought to be absorbed by cytochrome c oxidase, an enzyme in the cell's mitochondria. That is the leading explanation for how red and near-infrared light act on cells, at least up to about 950 nm.
| Wavelength | Colour | Where it works | What it has been tested for in people | On Kivorla |
|---|---|---|---|---|
| 460 to 480 nm | Blue | Skin surface, under 1 mm | The body clock: in 72 volunteers, 446 to 477 nm was the most potent band for suppressing melatonin. Hospital phototherapy for newborn jaundice uses 460 to 490 nm. Acne trials used shorter blue, about 415 to 445 nm. | Mask 460 (blue mode), panel 480 |
| 590 nm | Amber or yellow | Upper skin, about 0.5 to 2 mm | Wrinkle volume around the eyes fell 29.9% in a split-face trial of 137 women. Less redness the day after fractional laser in 20 patients. | Panel |
| 630 to 633 nm | Red | Skin, about 2 to 3 mm | Wrinkles and elasticity in a sham-controlled trial of 76 people (633 nm, 830 nm or both). Acne spots fell from about 28 to about 6 on the 630 nm side in a 28-person split-face trial. | Panel 630 |
| 660 to 670 nm | Deep red | Skin, about 2 to 3 mm | Wrinkle volume fell 31.6% in the trial of 137 women. Eye-area wrinkles improved over 12 weeks in a 52-woman trial of 660 nm against white light. Peak muscle force was 12% above placebo in a small crossover trial. | Mask 665, panel 660 and 670 |
| 700 to 770 nm | Far red | Not used | A stretch one major review calls likely to be disappointing, which is why charts jump from 670 to 810. | Neither |
| 810 nm | Near-infrared | Below the skin | Muscle strength and soreness after hard exercise in 28 soccer players. Much of the brain research uses 810 nm. | Panel |
| 830 nm | Near-infrared | Below the skin | Wrinkles and elasticity in the 76-person sham-controlled trial. Peak muscle force 14% above placebo. | Panel |
| 850 nm | Near-infrared | Below the skin | Exercise tolerance and recovery time in postmenopausal women training on a treadmill. Skin elasticity when paired with red in a 24-person split-face study. | Mask, panel |
| 1060 to 1072 nm | Deep near-infrared | Deepest of the set | Cold sore healing time (129 hours against 177 with a sham device, 87 people, 1072 nm). Fine lines around the eyes (1072 nm). Reaction time and memory tasks after a 1064 nm laser to the forehead in a 40-person placebo-controlled trial. | Mask 1064, panel 1060 |
The entries describe what each wavelength was studied for, often with clinic lasers or medical devices and on medical conditions. They are a map of the research, and are not a list of things a home device treats. The main trials are linked in the sections below. The others in the chart are the amber study after laser (Dermatologic Surgery, 2009), the 12-week eye-area trial at 660 nm (Dermatologic Surgery, 2017), the soccer players at 810 nm (Photomedicine and Laser Surgery, 2017), the treadmill trial at 850 nm (Lasers in Medical Science, 2013), the red and near-infrared split-face study (Journal of Cosmetic Dermatology, 2020) and the fine-lines trial at 1072 nm (Journal of Cosmetic and Laser Therapy, 2007).
What is the best wavelength for red light therapy?
There is no single best one. Choose by depth: red for the skin, near-infrared for muscles and joints, and red with near-infrared for a face.
When trials have compared wavelengths directly, the usual result is a tie.
- 633 nm against 830 nm for skin: a double-blind, sham-controlled trial gave 76 people 633 nm, 830 nm, both, or a sham light twice a week for four weeks. All three light groups improved, with wrinkle reductions of up to 36% and elasticity gains of up to 19%. Journal of Photochemistry and Photobiology B, 2007
- 660 nm against 590 nm for wrinkles: 137 women had red on one side of the face and amber on the other at the same dose for ten sessions. Wrinkle volume fell 31.6% with red and 29.9% with amber. Photobiomodulation, Photomedicine, and Laser Surgery, 2023
- 660 nm against 830 nm for muscle: in a placebo-controlled crossover trial, peak biceps force rose 12.14% with red and 14.49% with near-infrared, with no significant difference between them. Lasers in Medical Science, 2012
Where one wavelength did win, depth explains it. For acne, which sits at the surface, a 630 nm laser cut lesion counts from 27.7 to 6.3 while 890 nm on the other side of the face made no significant difference. Indian Journal of Dermatology, 2012 Through thick tissue the advantage runs the other way, as the next section shows.
Dose matters at least as much as the exact number. A review of 22 placebo-controlled trials in knee osteoarthritis found that near-infrared laser at the recommended dose reduced pain by 18.71 mm on a 100 mm scale, against 6.34 mm at other doses. BMJ Open, 2019 We cover how to choose between the two main bands in 660 nm vs 850 nm.
How deep does each wavelength penetrate?
Red light is mostly absorbed within 2 to 3 mm of skin and near-infrared reaches roughly 5 to 10 mm, with a small share travelling further. Depth generally rises with wavelength up to about 1,060 to 1,100 nm.
Every depth figure depends on how it is defined, whether as the point where a third of the light is left, a tenth, or any detectable amount, and that is why sources disagree on the millimetres while agreeing on the order. A direct measurement makes the order clear. Researchers shone a 633 nm and an 830 nm LED source through a living human cheek and measured what came out the other side: 2.1 to 4.0% of the red light and 12.0 to 15.0% of the near-infrared. PLoS ONE, 2012
There is one dip on the way. Past about 950 nm water begins to absorb more, and in a test through beef, 808 nm light penetrated as much as 54% deeper than 980 nm. Photomedicine and Laser Surgery, 2013 A computer model of skin also found that beams wider than about 10 mm lose little to scattering, which favours a mask or panel over a pen-sized device. Lasers in Medical Science, 2017
Is 660 nm the same as 670 nm? And 630 the same as 633?
For an LED, very nearly. The number on the label is the peak of a band a few tens of nanometres wide, so neighbouring LEDs overlap.
A standard optics reference gives the emission bandwidth of an LED as typically some tens of nanometres. RP Photonics A diode laser is far narrower, typically 1 to 2 nm, and a comparison of the two sources provisionally concluded that LEDs can stand in for lasers in most of the uses studied. Photochemical & Photobiological Sciences, 2018
Two things follow. A trial run at 633 nm is fair evidence for a 630 nm LED, and a trial at 660 nm for a 670 nm one. And having both 660 and 670 nm on a panel widens the red band it covers, with each still adjustable on its own. Our mask uses laser diodes with a narrow line at 665 nm, which sits in the middle of that 660 to 670 nm research band.
Why do the charts skip 700 to 770 nm?
Because that stretch has given weak results in laboratory work. Device makers build around the wavelengths on either side of it.
The same 2017 review says that between 700 and 770 nm "the results are likely to be disappointing". In a cell study that tested 670, 728, 770, 830 and 880 nm on neurons, 830 and 670 nm were the most effective, matching the absorption pattern of cytochrome c oxidase, and 728 nm was the least. Journal of Biological Chemistry, 2005
What do 1060 and 1064 nm add?
Reach. They sit at the long end of the optical window, between the water absorption bands near 970 and 1,200 nm, and travel deepest of the wavelengths on the chart.
In pig skin and beef muscle, 1064 nm light was transmitted slightly better than 905 nm through the first 10 mm. Biomedicines, 2023 The human trials in this band are at 1072 nm, including the sham-controlled cold sore trial of 87 people in the chart Clinical and Experimental Dermatology, 2013, and at 1064 nm with a laser on the forehead, where, in a trial of 40 healthy volunteers, the 20 given the laser did better on attention and memory tasks than the 20 given a placebo. Neuroscience, 2013 It is the newest band in home devices and its research is at an earlier stage than red or 830 nm. We go into it in deep near-infrared in a face mask and red light therapy for cold sores.
Where do blue and amber fit in?
They are surface wavelengths, used for different jobs from red. Blue acts at the top of the skin and on the body clock, and amber acts in the upper skin.
The body-clock finding comes from 627 overnight tests in 72 volunteers, which put the most potent band for melatonin suppression at 446 to 477 nm. Journal of Neuroscience, 2001 That is the reason to use blue in the morning or afternoon and to leave it off in the evening. Blue between 460 and 490 nm is also the standard light for treating newborn jaundice in hospital, the best-documented medical use of that exact band. Pediatrics, 2024 The acne trials used shorter blue, which we cover in blue light therapy. Amber has its own article, yellow light therapy, and all the colours are compared in LED light therapy colours.
Which wavelengths are not red light therapy?
Ultraviolet and far infrared. One tans and burns, the other heats, and neither is what a red light device emits.
- Ultraviolet, 100 to 400 nm: the light of sunbeds and sunburn. Red light devices emit none, which is why they do not tan, as explained in red light therapy and tanning.
- Far infrared, 3,000 nm and beyond: the radiant heat of infrared saunas. It is absorbed at the surface and warms the body, which is a different effect, compared in infrared vs red light therapy. ICNIRP
Which wavelengths do Kivorla devices use?
The mask uses four and the panel nine, covering every band on the chart that devices use, from blue to deep near-infrared.
| Device | Red | Near-infrared | Blue | Amber |
|---|---|---|---|---|
| 4-Wavelength Mask | 665 nm | 850 and 1064 nm | 460 nm (blue mode) | None |
| 9-Spectrum Panel | 630, 660 and 670 nm | 810, 830, 850 and 1060 nm | 480 nm | 590 nm |
On the panel each of the nine wavelengths dims from 1 to 100% on its own, so a session can be set to match its target: red and amber up for a face, near-infrared up for a knee or a back, blue off in the evening. The panel delivers at least 1567 W/m² at 6 inches and ships with goggles and a controller. The mask runs at 50 to 103 mW/cm² with a 5, 10 or 15-minute timer. What the extra bands on a panel give you is discussed in seven wavelengths or nine, and the other figures worth checking are in how to choose a red light therapy panel.
Standard shipping to the US, UK and Germany is free. Read the precautions before ordering, since returns are accepted within 30 days, less a 10% restocking fee if the device is unopened with its seals intact, or 20% if it is opened but undamaged and complete.
Kivorla devices are general wellness devices, not medical devices. The chart describes what published research on each wavelength examined, often with clinic lasers, and is not a list of conditions our devices treat. If you have a skin, eye or other medical condition, speak to a doctor before using a light device.