Red Light Therapy 101: Understanding Wavelengths, LED's and How it Works

What is Red Light Therapy?

Red light therapy, also known as photobiomodulation, is a non-invasive wellness therapy that uses specific wavelengths of red and near-infrared light to support the body's natural cellular processes. Unlike ultraviolet (UV) light, which is used for tanning, red and near-infrared light are not designed to tan the skin. Instead, these specific wavelengths interact with the body in different ways, supporting normal cellular function and the body's natural recovery processes. Because red and near-infrared light can reach different tissue depths, this technology is used for a variety of wellness applications, from supporting healthy skin to promoting recovery, mobility, and overall function.

Red light therapy has gained popularity because it offers a gentle, relaxing approach that may complement healthy lifestyle habits and other wellness services by supporting the body's natural ability to function and recover.

LED Count: Why More Doesn't Always Mean Better

LED stands for Light-Emitting Diode. LEDs are the individual light sources within a red light therapy panel that produce specific wavelengths of light.

When looking at red light therapy panels, you will often see the number of LEDs advertised as a major feature. The LED count tells you how many individual light sources are built into the panel, but it does not tell you the entire story.

The effectiveness of red light therapy depends on several important factors, including:

• Wavelengths of light produced — the specific type of light being delivered

• Irradiance (output) — how much light energy reaches the body

• Treatment area covered — how much of the body can be exposed at one time

• Distance from the panel — how close the body is positioned to the light source

• Length of each session — how long the body is exposed to the light

Each of these factors plays an important role in how red light therapy is delivered and experienced.

Wavelength: What Do the Numbers Mean?

Wavelength is measured in nanometers (nm) and tells us the specific type of light being produced. Different wavelengths interact with the body differently because they penetrate to different depths.

Red light (approximately 630-660 nm) is visible light that is generally absorbed more superficially and is commonly studied for applications involving skin and other surface-level tissues.

Near-infrared light (approximately 810-850 nm and beyond) is invisible to the eye and can penetrate deeper into tissue. These wavelengths are commonly studied for their potential effects on muscles, joints, and other deeper tissues.

Irradiance (Output): How Much Light Energy Reaches Your Body?

Irradiance refers to the amount of light power being delivered to a given area of the body. It is measured in milliwatts per square centimeter (mW/cm²).

Think of irradiance as the strength or intensity of the light being delivered at a specific distance from the panel. A higher irradiance means more light power is being delivered to a given area of the body in the same amount of time.

This is why treatment time and positioning matter. A higher-output panel may require a shorter session or a greater distance, while a lower-output device may require longer exposure times.

Treatment Area: How Much of the Body Is Being Exposed?

Another important factor in red light therapy is the treatment area—how much of the body can be exposed to the light during a session.

Some red light therapy devices are designed to target smaller areas, such as the face or a specific body part. Other systems are designed to provide larger areas of coverage, allowing light to reach more of the body at one time.

The size and design of the panel can influence the overall treatment experience. A larger treatment area may allow for more complete exposure, while smaller devices may require treating one area at a time.

When considering a red light therapy system, it is important to understand how much of the body is being exposed and how the device is intended to be used.

Distance From the Panel: Why Positioning Matters

The distance between your body and the red light therapy panel plays an important role in how much light energy reaches your body.

As you move closer to a light source, the intensity of the light generally increases. Moving farther away decreases the amount of light energy reaching the body. This means distance and output work together when determining the appropriate amount of light exposure during a session.

Proper positioning allows the amount of light reaching the body to be considered along with the device’s output and treatment time. More light or a closer distance is not always better—the goal is to deliver an appropriate amount of light for the individual and the intended purpose.

Length of Each Session: Why Time Matters

The length of a red light therapy session is another important factor in how the therapy is delivered. Session time is influenced by several factors, including the wavelengths being used, the output of the device, the distance from the panel, and the area being treated. A higher-output system may require a shorter session, while a lower-output device may require a longer exposure time.

More time is not always better. Red light therapy is designed around delivering an appropriate amount of light energy rather than simply spending as much time as possible under the panels.

Consistency is also important. Like many wellness practices, regular sessions over time are generally more beneficial than occasional sessions, even if those sessions are longer.

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