Differences Between Red Light and Near-Infrared Light in Photobiomodulation

To better understand: two types of light, two effects

Red light and near-infrared light are often used together in photobiomodulation. But they don't do exactly the same thing. An overview will help you make the right choice.

Red light: wavelengths

Red light typically falls within the range of 600 to 700 nm. This range encompasses several shades of red. It penetrates less deeply than near-infrared light.

Key Features

• Wavelengths: 600–700 nm (often centered around 650 nm)
• Tissue permeability: superficial to moderate
• Visual sensitivity: visible to the human eye

Back to the table of contents

Near-infrared: wavelengths

Near-infrared (NIR) generally ranges from 700 to 1100 nm. It is invisible to the naked eye but very effective at penetrating deep into the tissue.

Key Features

• Wavelengths: 700–1100 nm (often centered around 850–980 nm)
• Tissue permeability: deep
• Visual sensitivity: not visible to the human eye

Back to the table of contents

Penetration and Depth

This is a major difference. The depth of penetration determines which tissues the light can reach.

• Red light: generally penetrates 1–2 mm into the skin
• Near-infrared: generally penetrates 2–5 mm, or even deeper depending on tissue composition

This difference explains why one or the other is chosen depending on the target: superficial skin versus deeper tissues.

Back to the table of contents

Expected Biological Effects

Both types of light interact with the same cellular chromophores, particularly cytochrome c oxidase. However, because of their different penetration depths, they target slightly different cell populations.

• Red light: primarily on keratinocytes, fibroblasts, and cells in the superficial layer
• Near-infrared: also reaches deeper tissues such as the deep dermis, the hypodermis, or the muscles

Back to the table of contents

Combined Use

Many modern protocols combine the two. This is often the best approach when you want to cover multiple tissue layers.

Benefits of the wetsuit

• Optimal coverage: both superficial AND deep
• Enhanced biological response: possible synergy
• Flexibility: Adjust as needed

Back to the table of contents

Choosing Between Red and NIR: Practical Guides

Select the red light if

• The focus is on visible skin (face, exposed areas)
• Goal: radiance, texture, or superficial discomfort
• Preference for a simpler, less powerful device

Choose near-infrared if

• Target: muscles, joints, or deeper tissues
• Pain or discomfort extending beyond the skin's surface
• Sports Recovery or Muscle Support

Choose both if

• Multidimensional target: skin AND deep tissues
• A device capable of combining the two wavelengths
• Advanced Protocol for Optimal Results

Back to the table of contents

Summary and Recap

Back to the table of contents

See also

• Definition and Uses
• Cellular mechanisms
• Choose a device