660nm vs. 850nm: What the Two Numbers on a Red Light Panel Actually Mean

Almost every red light panel lists 660 and 850 somewhere on the box. Those are wavelengths, a fancy word for the color of the light, measured in nanometers. They are the two numbers that matter more than LED count, panel size, or wattage when you are deciding whether a panel does what it claims.

What do the numbers describe?

• 660 nm is visible red light. You can see it glowing when the panel is on.
• 850 nm is near infrared light, invisible to the eye.

A panel that only lists a 660 number and nothing else is red light only. A panel with both covers the red and the near infrared ranges in the same session. Some full-spectrum panels add a third figure around 1064, a longer near infrared wavelength. More numbers on a spec sheet is not automatically better, but a panel that says only "red light" with no wavelength is not telling you which one it is.

Why two numbers instead of one?

Published research on red light works in the red and near infrared ranges, and the thing most often studied as the light absorber is an enzyme inside your cells' mitochondria, which is involved in how cells make energy (Hamblin, 2018; Karu, 2008). A single-wavelength panel covers one range. A panel with both 660 and 850 covers both in one session, which is the reasoning most full-body panels give for including both rather than picking one.

What does the number list not tell you?

Wavelength is only one spec. It says nothing about how strong the light is where it lands, which depends on LED quality, distance, and panel design. Two panels can list identical 660 and 850 numbers and still put out very different amounts of light at the same distance. If a listing gives you wavelengths but no strength at a stated distance, you have half the information you need.

What should you take away when comparing panels?

• Two wavelength numbers, not one, is standard on a full-body panel.
• 660 and 850 are the two to look for by name. A panel that just says "red light therapy" is giving you a category, not a spec.
• Wavelength tells you which kind of light it is. It does not tell you how much light you are getting, which is a separate number worth asking for.

Common questions

What is 660nm light?

Visible red light. You can see it glowing when the panel is on.

What is 850nm light?

Near infrared light, invisible to the eye.

Why do red light panels list two wavelengths?

Published research on red light works in the red and near infrared ranges. Full-body panels often include both.

What does the wavelength number not tell you?

How much light reaches your skin. Two panels with identical 660 and 850 numbers can put out very different amounts at the same distance.

What does 1064nm mean on a panel?

A longer near infrared wavelength that some full-spectrum panels add.

Where to start

Light is usually the easiest of the three inputs to add first, since it starts in week 1 of every Peak Regenerate protocol no matter the tier. Find My Protocol matches your sleep, recovery, activity level, schedule, and heat and cold experience 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

For the full spec breakdown, see Red light therapy: wavelengths, timelines, and what the research measures.

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.