At the time I was skeptical but after a week and a half use one feels its benefits, it is probably psychological.
This year I was able to test a small model in blue light, which never leaves my office.
After my session 30 minutes past it is not unusual that my little model happens on the desktop of my colleague.
This light therapy m accompanies for 10 years and I m avoids ingesting vitamins and other expensive supplements
This model is a bit expensive but if its share leds it takes so long that my Brightlight I've never changed the bulb, the investment per year is minimal.