Red Light Therapy Wavelengths Explained: 630nm vs 660nm vs 810nm vs 850nm

When you shop for a red light therapy device, you'll see numbers like "660nm" and "850nm" in the product specs. These wavelengths matter — they determine what the device is good for. Here's the complete breakdown of every wavelength used in RLT.

What Are Wavelengths?

Light is electromagnetic radiation that travels in waves. The wavelength — the distance between successive peaks of the wave — determines the light's color (if visible) and its properties. Wavelengths are measured in nanometers (nm), where 1 nm = one billionth of a meter.

The visible light spectrum (what human eyes can detect) ranges from about 380nm (violet) to 750nm (deep red). Below 380nm is ultraviolet (UV), which is invisible and damaging to skin. Above 750nm is infrared, which is invisible but felt as heat.

For red light therapy, the relevant wavelengths are 600–1000nm — the red and near-infrared range. Within this range, specific wavelengths have been more studied than others, and some are more effective for specific conditions.

Visible Red Light (620–700nm)

630nm

Used in many LED face masks (CurrentBody, Dr. Dennis Gross). Strong clinical evidence for collagen stimulation and wrinkle reduction. Penetrates 1–2mm into the skin, reaching the epidermis and upper dermis. Best for surface skin concerns.

633nm

Very similar to 630nm; some devices use 633nm instead. Strong evidence for skin rejuvenation. Often paired with 830nm in clinical settings.

660nm

The most common red light wavelength in panels (Mito Red, Hooga). Penetrates 2–5mm, reaching the dermis where collagen is made. Slightly deeper penetration than 630nm. Strong evidence for wound healing, wrinkle reduction, and surface inflammation.

670nm

Less common, but used in some LLLT hair regrowth devices. Similar effects to 660nm.

Near-Infrared (800–1000nm)

810nm

The wavelength most studied for brain effects (transcranial photobiomodulation). Penetrates 5–10mm, reaching subcutaneous tissue and potentially the brain through the skull. Early evidence for TBI, depression, and cognitive decline. Used in the Bestqool panel.

830nm

Common in LED masks (CurrentBody Series 2, HigherDOSE). Penetrates 5–10mm, reaching muscle and joint tissue. Strong evidence for deep tissue healing and anti-inflammation. Often paired with 633nm.

850nm

The most common NIR wavelength in panels (Mito Red, Hooga). Very similar effects to 830nm. Strong evidence for muscle recovery, joint pain, and deep-tissue inflammation.

940nm

Less common, but included in some pain-relief wraps (Comfhouse Knee Wrap). Limited clinical evidence, but may have slightly deeper penetration than 850nm.

Other Wavelengths You'll See

415nm (Blue Light)

Used in acne treatment devices (Dr. Dennis Gross FaceWare Pro). Kills acne-causing bacteria (Cutibacterium acnes) by damaging their porphyrins. Not technically "red" light, but often combined with red light in acne devices.

590nm (Yellow Light)

Used in some multi-color masks. Limited evidence for reducing redness and inflammation. Not a primary therapeutic wavelength.

Far-Infrared (3000nm+)

Used in infrared saunas. Felt as heat. Different mechanism from RLT — primarily heats tissue rather than stimulating cellular function. Not the same as red light therapy.

Which Wavelengths Actually Matter?

For most users, the only wavelengths that matter are:

• 660nm (red) — for skin
• 850nm (NIR) — for pain and recovery

If your device has these two wavelengths, you're covered for 95% of RLT use cases. Additional wavelengths (630nm, 810nm, 830nm) are nice to have but not essential.

The exception: for acne, you also need 415nm blue light. And for hair regrowth, you need 655–670nm (LLLT devices like iRestore).

Don't be distracted by devices advertising 5+ wavelengths. More isn't better — focus on the wavelengths with the strongest clinical evidence for your specific goal.

Frequently Asked Questions