During this procedure, different wavelengths and outputs of low-level light are applied directly to a targeted area. The body tissue then absorbs the light. The red and near-infrared light cause a reaction, and the damaged cells respond with a physiological reaction that promotes regeneration.
Superficial tissue is commonly treated with wavelengths between 600 and 700 nanometers (nm). For deeper penetration, wavelengths between 780 and 950 nm are used.
Although you’ll feel the laser device touching your skin, the procedure is painless and noninvasive. There will be no sound and you’ll feel no vibration or heat. Each treatment typically takes only a few minutes.
Source – Healthline