Light Therapy: SAD Lamps and Red Light, What the Trials Support
Not medical advice. Depression is a clinical diagnosis and light therapy interacts with bipolar disorder, retinal disease and photosensitizing drugs; use it with a clinician where any of those apply.
Quick answer
Two device categories with real trials and a shelf that does not state the numbers the trials used. Bright light boxes are dosed in lux at a distance and most listings state the lux without the distance; red light skin devices are dosed in milliwatts per square centimetre and few listings state it at all. We read 71 lamp listings and 113 skin-device listings, checked every brand in the FDA’s 510(k) database, and track 8 lamps and 8 skin devices with the numbers that can be verified.
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Frequently asked questions
Is a SAD lamp the same as a red light therapy device?
No. A SAD lamp is a bright white light box, 10,000 lux at the eye for about 30 minutes in the morning, and it treats seasonal and nonseasonal depression through the retina and the body clock. A red light device delivers red (about 660 nm) and near-infrared (about 830 to 850 nm) light to the skin at a stated dose to affect wrinkles and texture; you do not look at it. Neither emits the ultraviolet B that makes vitamin D.
Do light therapy devices need FDA clearance?
Bright light boxes are sold as general wellness products and no maker on our SAD-lamp page has a 510(k) for one; the trials are the evidence. Red light skin devices sold for wrinkles or acne are cleared through the FDA's 510(k) process as substantially equivalent to earlier devices, and the clearance is a public record we look up by brand and device; several listings claim it with no record under their name.