Red Light Therapy: Wavelengths, Timelines, and What the Research Measures
Red light panels list wavelengths in nanometers: 630 and 660 are visible red, and 810 to 850 (sometimes 1064) are near infrared. How strong the light is only means something with a stated distance. Published skin studies ran sessions two or more times a week for one to three months, so judge a panel over weeks, not days.
Red light panels come with a lot of numbers on the box and not much explanation of what they mean. This article covers the wavelengths, what "dose" and "strength" mean, how long the studies actually ran, and what the research supports. The science term for all this is photobiomodulation, which means using specific colors of light to affect cells. "Red light therapy" is the common name, so that is what we use.
What do the wavelengths on a panel mean?
Panels list wavelengths in nanometers (nm), which you can think of as the color of the light. The ones that come up most:
- 630 and 660 are visible red light.
- 810, 830, and 850 are near infrared, invisible to the eye.
- 1064 is a longer near infrared wavelength that some full-spectrum panels add.
A panel that lists several of these covers both the red and near infrared ranges. What matters when you compare panels is which wavelengths are actually included, how many LEDs there are, and the measured output, not the length of the number list.
What are irradiance and dose?
Two words do most of the work, and neither is as scary as it sounds.
- Irradiance is how strong the light is where it lands, measured in milliwatts per square centimeter. It drops quickly as you move away from the panel, so a figure only means something with a distance attached. "Strength at 6 inches" is a real spec. "Strength" with no distance is marketing.
- Dose is strength multiplied by time, the total amount of light your skin gets in a session.
More is not automatically better. Some of the research describes a range where an effect shows up, and going far above it adds nothing and can reduce it. That is why sessions are timed rather than "as long as possible."
What is the light thought to do?
The most studied idea involves the mitochondria, the parts of your cells that produce energy. Red and near infrared light is absorbed by an enzyme in the mitochondria, and that absorption is studied in relation to how cells make energy (Hamblin, 2018; Karu, 2008). It is a mechanism under study, not a finished result. The jump from "the light is absorbed here" to "you will see a specific outcome" is the step the research is still working on, and it depends heavily on wavelength, dose, and the type of tissue.
A broad review of this field across muscle and other tissues shows how wide it is and how early much of it still is (Ferraresi and colleagues, 2012).
How long does red light take?
Red light research does not report overnight changes. Studies on skin, for example, ran sessions two or more times a week over one to three months.
One controlled trial treated volunteers about twice a week and checked them after about 30 sessions. Red and near infrared light exposure was associated with improvements in skin appearance and collagen density in that study (Wunsch and Matuschka, 2014). A wider review of light and skin covers similar ground (Avci and colleagues, 2013).
The practical point: if you buy a panel, judge it over weeks of regular use, not days. It is associated with improvements in skin appearance in published research. It is not a treatment for any skin condition.
What does the research not establish?
- It does not show that a red light panel treats, cures, or prevents any disease or medical condition.
- Effects depend on wavelength and dose. A panel that does not publish its strength at a stated distance is hard to evaluate.
- Claims about fat loss, hair, and hormones from red light are, in humans, early and inconsistent.
- A red light panel is a general wellness device, not medical equipment.
Common questions
What do 660nm and 850nm mean on a red light panel?
660 is visible red light and 850 is invisible near infrared light. A panel listing both covers the red and near infrared ranges.
What is irradiance on a red light panel?
How strong the light is where it lands, in milliwatts per square centimeter. It drops quickly with distance, so a figure only means something with a stated distance, such as at 6 inches.
What is dose in red light therapy?
Strength multiplied by time, the total light your skin gets in a session. Sessions are timed rather than as long as possible.
How long does red light therapy take to show results?
Research does not report overnight changes. Skin studies ran sessions two or more times a week over one to three months, and one controlled trial checked volunteers after about 30 sessions.
How does red light work?
The most studied idea is that an enzyme in the mitochondria absorbs the light, which is studied in relation to how cells make energy. It is a mechanism under study, not a finished result.
Does red light therapy treat any condition?
No. The research does not show that a red light panel treats, cures, or prevents any disease or medical condition. It is a general wellness device.
Where to start
Light is usually the easiest of the three inputs to add first, because it asks the least of you physically. Where it sits compared to cold and heat, and how fast you add those, depends on your sleep, recovery, activity level, schedule, and how much heat and cold you already do.
Find My Protocol matches those five answers to a starting point and a week by week plan. It takes about two minutes and does not require a purchase.
References
- Hamblin MR. Photochemistry and Photobiology. 2018;94(2):199 to 212. PMID 29164625. pubmed.ncbi.nlm.nih.gov/29164625
- Karu TI. Photochemistry and Photobiology. 2008;84(5):1091 to 1099. PMID 18651871. pubmed.ncbi.nlm.nih.gov/18651871
- Ferraresi C, Hamblin MR, Parizotto NA. Photonics and Lasers in Medicine. 2012;1(4):267 to 286. PMID 23626925. pubmed.ncbi.nlm.nih.gov/23626925
- Wunsch A, Matuschka K. Photomedicine and Laser Surgery. 2014;32(2):93 to 100. PMID 24286286. pubmed.ncbi.nlm.nih.gov/24286286
- Avci P, et al. Seminars in Cutaneous Medicine and Surgery. 2013;32(1):41 to 52. PMID 24049929. pubmed.ncbi.nlm.nih.gov/24049929
For the full protocol details, see the protocol guide.
The products sold by Peak Regenerate are sold for general wellness use only and are not intended to diagnose, treat, cure, or prevent any disease or medical condition. This article is for educational and informational purposes only. Talk to your physician before starting any heat, cold, or light exposure routine, especially if you have a heart condition, are pregnant, or take prescription medication. Individual results vary. Peak Regenerate does not provide medical services through this platform.
