Do light boxes actually work for SAD?
Last updated September 3, 2026.
Yes - NIMH lists light therapy as a first-line treatment for winter-pattern SAD, backed by decades of trials. The dose separates working from decorative: a 10,000-lux box, at the specified distance, 20 to 30 minutes within the first hour of waking, daily through the dark season. Many notice a difference within one to two weeks. Cautions: bipolar disorder needs clinician supervision (bright light can trigger hypomania), eye disease and photosensitizing meds need a doctor's okay, and evening use can wreck sleep.
What to do
- Get the right box. 10,000 lux, UV-filtered, sized to sit at the specified distance.
- Use it in the morning. First hour after waking, daily - consistency is the mechanism.
- Clear the cautions first. Bipolar history, eye disease, photosensitizing meds: ask a clinician.
- Stack the pillars. Light plus CBT plus outdoor morning light beats any one alone. In crisis: 988 in the US, or your local crisis line.
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