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Man reading a book while sitting in front of a light box


Light boxes, also known as bright light therapy boxes or phototherapy boxes, are promoted for relieving seasonal affective disorder (SAD) or "winter depression," and for certain circadian rhythm disorders. These products are designed to mimic outdoor light. Experts believe that exposure to light boxes helps suppress the release of melatonin, a hormone that maintains the sleep-wake cycle and that is overproduced in people with SAD, and increase the production of serotonin, a brain chemical that affects mood and tends to be lower in people with SAD. By normalizing levels of serotonin and melatonin, bright light therapy is believed to help regulate the body's daily rhythm to improve mood, sleep, and behavior (National Institute of Mental Health, Seasonal Affective Disorder Fact Sheet).

Use of light boxes can help treat SAD in people with mild to moderate symptoms. It is unclear if light boxes help prevent SAD. Light boxes have shown modest benefit in improving sleep in people with certain circadian rhythm disorders. People considering light boxes for SAD should be sure to select a device that provides 10,000 lux of light at a specified distance from the device. The device should not emit a significant amount of UV light, and it should have a large, illuminated surface area.

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  • Are light boxes effective for treating or preventing SAD?
  • Who is most likely to benefit from a light box?
  • How should light boxes be used by people with SAD?
  • Are light boxes effective for circadian rhythm disorders?
  • Which light boxes meet the requirements? (See our recommendations)
  • Is light therapy safe? Who should not use a light box?
  • Are light boxes covered by insurance?
  • Can you make your own light box?
  • Do bright light glasses reduce symptoms of depression or improve sleep?

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