Bright Light and the Human Brain

Light works through our eyes. (This is different from how vitamin D is produced, which is by UV light reaching our skin.) When bright light enters the eyes, it stimulates specialized receptor cells in the retina that have connections to the suprachiasmatic nucleus in the brain – the "master pacemaker." From there, the effects spread – more widely than doctors and scientists once thought.

Bright light sets the rhythms of our bodies, our minds, and our lives. When those internal rhythms are out of sync with our day, we feel "social jet lag." But it’s not just a feeling. "Circadian synchronization" improves sleep, mood, alertness, cognitive performance, and well-being.

SunSprite infographic

Scientific studies over the last 30 years have concluded that light therapy is just as effective as antidepressant medication not only for seasonal depression (SAD) but also for non-seasonal depression. And further research has found that bright light may also benefit a wide range of medical conditions including insomnia, ADHD, Parkinson’s disease, and dementia.

Light is easy to get – if it's bright enough, you only need 30 minutes a day. And because the beneficial effects of bright light come through your eyes, you don't even need to be outside. Small lifestyle changes, like eating your breakfast while facing a sunny window, can make all the difference.

For a more in-depth look at the hard science behind bright light and its benefits, check out the White Paper and article in the Harvard Review of Psychiatry written by our medical co-founders, who are Associate Clinical Professors, Part Time at Harvard Medical School and who recommend bright light to their patients in their private practices.