What is Radiance in Red Light Therapy?Updated 7 hours ago

Radiance is the amount of light power reaching your body, measured in mW/cm². It determines how quickly a red light therapy device can deliver a therapeutic dose. Higher radiance generally means shorter treatment times, but the most important factor is achieving the correct energy dose rather than simply using the highest power setting available. 

Radiance (irradiance) is a measurement of how much light energy is reaching a specific area of the body. 

In red light therapy, it is usually expressed as: 

mW/cm² (milliwatts per square centimetre) 

This tells you the power density of the light hitting your skin. 

Simple Example 

Imagine two garden hoses: 

• Hose A sprays a gentle stream of water. 
• Hose B sprays a much stronger stream. 

Both use water, but Hose B delivers more water to the same area. 

Radiance works similarly: 

• Low radiance = less light energy reaching the skin. 
• High radiance = more light energy reaching the skin. 

Why is Radiance Important?

Radiance determines how quickly a therapeutic dose of light can be delivered. 

For example: 

A higher radiance panel can typically achieve the same energy dose in a shorter session.

Why Distance Matters

Radiance decreases as you move away from the panel. 

Example: 

This is why reputable manufacturers specify the measurement distance.