How deep does the lights go?Updated a year ago

The infrared light can reach up to 2 inches down the skin while the red light reaches 1 inch. There's an article about this, "Infrared light penetrates to the inner layers of the skin at about 2 to 7 centimeters deep. Hence, it reaches the muscles, nerves and even the bones." - https://www.news-medical.net/amp/health/How-Does-Infrared-Therapy-Work.aspx