How deep does red light therapy penetrate the skin?

Penetration depth depends on the wavelength used.

Red light (around 630nm–660nm) typically penetrates a few millimeters into the skin. This is sufficient to reach the dermis, where collagen production occurs. That’s why it’s so effective for improving skin quality.

Near-infrared light, however, can penetrate significantly deeper—sometimes several centimeters into the body. This allows it to reach muscles, joints, and even certain internal tissues.

It’s important to understand that penetration is not just about depth, but also about energy delivery. A device must have sufficient power output to ensure that enough light reaches the target tissue.

In practical terms, this means that both wavelength and device quality determine effectiveness. A low-powered device may not deliver enough انرژی to deeper tissues, even if it uses the correct wavelength.