Red Light Therapy: What 660nm and 850nm Actually Do
Updated July 2026 · Cool Bionic Research
The short answer
Red and near-infrared light are absorbed by an enzyme inside your mitochondria called cytochrome c oxidase, and research suggests this interaction influences how cells produce energy. The number on the panel, measured in nanometers, tells you how deep the light reaches. Shorter red wavelengths like 630nm and 660nm are absorbed near the surface of the skin. Longer near-infrared wavelengths like 810nm, 830nm, and 850nm pass through skin to reach muscle and joint tissue, and 960nm and 1060nm reach deeper still. That is the whole idea behind a multi-wavelength panel: different depths, one device. This is a wellness practice, not a medical treatment, and the research below is framed cautiously for that reason.
What is photobiomodulation, in plain terms?
Photobiomodulation, often shortened to PBM, is the technical name for what red light therapy does. The mechanism most cited in the literature is straightforward at a high level. Light in the red and near-infrared range is absorbed by cytochrome c oxidase, a protein in the mitochondria that sits at the end of the cellular energy chain. According to a widely referenced review by Hamblin, 2017 in AIMS Biophysics, this absorption is followed by secondary effects that include increased ATP production, a brief burst of reactive oxygen species that acts as a signal, and a release of nitric oxide.
That same review makes one point worth remembering before you buy anything: PBM shows a pronounced biphasic dose response. Low doses tend to stimulate, and high doses can inhibit. More light is not automatically better. This is why dose, not just power, matters.
The wavelength map: which band reaches how deep
Wavelength is the single most useful spec on a red light panel because it maps to depth. A computational modelling study by Ash et al., 2017 in Lasers in Medical Science examined how penetration through tissue changes with wavelength, and the general pattern it supports is that longer near-infrared wavelengths reach deeper than shorter red ones.
Here is how the seven wavelengths on our Solis panel line up with that idea.
| Wavelength | Band | General depth target |
|---|---|---|
| 630nm | Red | Surface skin |
| 660nm | Red | Surface skin |
| 810nm | Near-infrared | Deeper tissue, muscle |
| 830nm | Near-infrared | Deeper tissue, muscle |
| 850nm | Near-infrared | Deeper tissue, muscle |
| 960nm | Near-infrared | Deepest reach |
| 1060nm | Near-infrared | Deepest reach |
The red band, 630nm and 660nm, is the one you see as visible red light. It is absorbed close to the surface, which is why most of the skin research uses this range. The near-infrared band, 810nm through 1060nm, is mostly invisible to your eye and is the band associated with deeper tissue in the literature. Our Solis panel, at S$1,840, carries all seven of these wavelengths across 308 LEDs, which is why the product framing is simply “surface skin repair through deep tissue,” honestly matched to the depth pattern above rather than to any promise of an outcome.
What has the research actually observed?
Three points before the studies. First, most of this work is early or mixed. Second, findings observed in a controlled trial are not a guarantee for any individual. Third, none of this treats, cures, or prevents disease. With that framing:
- Skin, red band. A controlled trial by Wunsch and Matuschka, 2014 in Photomedicine and Laser Surgery enrolled 136 people and used red and near-infrared light. Using objective measures, ultrasound for intradermal collagen density and profilometry for skin roughness, the study reported statistically significant improvements versus the control group. This sits squarely in the 630 to 660nm surface band.
- Muscle and performance, near-infrared band. A review by Ferraresi et al., 2016 in the Journal of Biophotonics looked at PBM used before and after exercise in athletes. It is worth reading as a balanced picture: the authors sorted study parameters into those that showed a positive effect and those that showed none. The honest summary is that results depend heavily on dose and timing, and the evidence is mixed rather than settled.
- Mechanism, all bands. The Hamblin, 2017 review already cited remains the clearest description of why any of this might happen at the cellular level.
If you want the cold exposure counterpart to this evidence discussion, our cold validation data page applies the same “what has actually been observed” standard to cold water immersion.
Irradiance and dose: why the distance matters
Wavelength tells you depth. Irradiance tells you intensity. Irradiance is measured in milliwatts per square centimeter, written mW/cm2, and it describes how much light energy lands on a given patch of skin each second. The dose you actually receive is roughly irradiance multiplied by time, which is why two numbers matter together, not power alone.
Irradiance falls off quickly as you move away from the panel, so any irradiance figure is meaningless without the distance it was measured at. Our Solis panel is specified to exceed 217mW/cm2 at 3 inches, easing to about 128mW/cm2 at 6 inches, which shows exactly how fast the number falls as you step back. That distance is the key part of the claim. A higher irradiance means you reach a given dose in less time, but the biphasic dose response from the Hamblin review is the reason we frame this as “reach your dose efficiently” rather than “more is better.” Sit closer or longer without thinking about total dose and you can overshoot the useful range.
Flicker and EMF: why they matter for daily use
Two quieter specs matter if you plan to use a panel regularly. Flicker is rapid fluctuation in light output that you may not consciously see. Flicker-free output removes that variable from a practice you might repeat several times a week. EMF, electromagnetic field emission, is the second. A zero-EMF design means no electromagnetic interference near the panel during use.
Our Solis panel is built with zero EMF and no flicker, which is the plain reason it is described as suitable for extended daily sessions. These are engineering choices about comfort and consistency for repeated use, not health claims.
Pulsing: 1 to 999Hz, and what the evidence says
Some panels can pulse the light on and off at a set frequency rather than running continuously. Solis offers independent pulse control from 1 to 999Hz per wavelength, set from the onboard controls, the remote, or the companion app. The practical engineering benefit is that pulsing cuts heat buildup while allowing higher peak output per session.
Does pulsed light do more biologically than continuous light? Here the honest answer is that the evidence is early and unsettled. A review by Hashmi et al., 2010 in Lasers in Surgery and Medicine surveyed the literature from 1970 to 2010. Of nine studies that directly compared continuous-wave against pulsed light, six found pulsed more effective. The authors concluded that pulsing can differ from continuous output, but that more work is needed and there is no consensus on the optimal pulse parameters. So: pulse control is a real capability, and the research is interesting, but nobody can hand you a settled “correct” frequency yet.
Session practice: general conventions, not a prescription
A common convention in general use is sessions of roughly 10 to 20 minutes at a set distance, done several times a week. Treat that as a starting point that people commonly use, not as medical advice or a first-party prescription from us. The two things worth being deliberate about, drawn from the research above, are distance, because it sets your irradiance, and consistency, because most studies ran over weeks, not single sessions.
Red light pairs naturally with the rest of a recovery routine. Many owners run a panel session as part of a broader stack that includes cold exposure and sleep timing. See our pages on the hormesis principle and circadian rhythm synchronization for how those pieces fit together, and our learn hub for the full set.
How Solis is built for this
The LightForge Solis Red Light Panel is our answer to the depth question above. It carries 630, 660, 810, 830, 850, 960, and 1060nm in one unit across 308 LEDs, exceeds 217mW/cm2 at 3 inches, runs zero-EMF and flicker-free, and offers independent brightness and pulse control per wavelength from 1 to 999Hz, with 12 preset modes and a built-in session timer. It ships with the panel, a power cable, a remote control, protective goggles, and a complete door and wall hanging kit, and is controlled from the onboard screen, the remote, or the companion app. At S$1,840, it is a single device that spans the full red and near-infrared range rather than a fixed one or two wavelengths.
Solis is a standard item, so it ships in 1 to 3 working days within Singapore. It carries our standard warranty of 12 months, with a free extension to 18 months via registration. If you would rather see it in person, our Singapore showroom is at UBI TECH PARK, 10 UBI CRESCENT (408564), and you can reach us any time on WhatsApp or through our contact page.
Pairing red light with cold is a common recovery approach in Singapore, where it is warm and humid year round and a cold plunge is a genuine contrast. Our Vitalis 3 ice bath is the cold side of that routine.
FAQ
Is 660nm or 850nm better?
Neither is better in general. They do different jobs. 660nm is red light absorbed near the skin surface, and 850nm is near-infrared that reaches deeper tissue. A panel that carries both, like Solis, covers both depths rather than forcing a choice.
What does mW/cm2 mean, and why does distance matter?
It is irradiance, the amount of light energy hitting each square centimeter of skin per second. It drops quickly as you move away from the panel, so a figure only means something with its distance attached. Solis is specified to exceed 217mW/cm2 at 3 inches.
How long should a session be?
A common convention is roughly 10 to 20 minutes at a set distance, several times a week. That is general practice, not a prescription. The two variables worth controlling are distance and consistency over weeks.
Does pulsed light work better than continuous?
The evidence is early. A 2010 review found that of nine direct comparisons, six favored pulsed light, but the authors stressed there is no consensus yet on the best settings. Solis offers 1 to 999Hz pulse control so you have the capability as the research develops.
Is red light therapy a medical treatment?
No. It is a wellness practice. The research described here is framed cautiously and does not claim to treat, cure, or prevent any disease. If you have a medical condition, speak with a qualified professional.
What is the warranty and delivery on Solis?
Solis carries a 12-month standard warranty with a free extension to 18 months via registration. As a standard item it ships within Singapore in 1 to 3 working days.