What is the difference between red light and Near Infrared light?

The difference is in the wavelengths: 620 – 750 nm for red light, and 750 – 850 nm for Near Infrared light (NIR). Red light is also visible to the human eye, while infrared is not. The red light doesn’t penetrate as deep into your body tissues. NIR goes deeper and can actually reach central parts of the brain and also internal organs.