Colors influence the energetic aspects of humans. Colored light in the cupping glass works via the nerve receptors and the aura of the person. The subtle body is surrounded by colors. Each of the 7 chakras has its own color.
Effects of colours on the body
green: calming and balancing
red: invigorates and vitalizes
blue: has a lymphatic effect
purple: takes the stress off. Violet is the strongest yin color
If you feel overloaded, green has a balancing, calming effect.
Reference: Book “Licht-Wellness“ by Monnica Hackl