Light therapy is the use of artificial or man-made sources of light to provide the amount necessary to promote good physical and mental health. This disorder occurs during seasons and locations of limited natural sunlight. In the northern hemisphere, hours of daylight decrease significantly as one moves further north in the winter. Suntan parlors and boxes are not light therapy. They can cause severe skin damage.
Light therapy is promoted for use in unproven and potentially harmful ways.
It may be offered as an alternative to conventional treatment for various problems. Examples of light therapy are UV light therapy and colored light therapy. It does not work. Colored light therapy is the promotion of lights of various colors to treat sleep disorders, shoulder pain, diabetes, impotence, and allergies, among other health problems. Blue, red, and violet lights are most commonly used.