Blue Light Therapy
Blue wavelengths (415–450nm) kill acne-causing bacteria at the skin surface, regulate circadian rhythm, and are used clinically for skin conditions and seasonal affective disorder.
This section covers two different treatments. Blue light at 415nm targets acne bacteria at the skin surface. Bright white light boxes treat seasonal depression, and the trials used about 10,000 lux at the eyes for about 30 minutes a day. Compare light boxes by lux at a stated distance, not by the headline number.
What the evidence supports
Grades come from the trials each guide cites. Follow a row to the evidence.
All guides (7)
When to Start Using a SAD Lamp
When should you start using a SAD lamp? The evidence supports morning sessions and a consistent routine, but no trial tested the calendar question. Here is how to time your season.
Oct 7, 2026
ReadDo SAD Lamps Actually Work?
Do SAD lamps work? The Can-SAD trial found light therapy matched fluoxetine for seasonal depression. Here is what the evidence supports and where marketing claims go beyond it.
Oct 5, 2026
ReadHow to Choose a SAD Lamp
A measured guide to choosing a SAD lamp: why 10,000 lux is only a starting point, and how distance, screen size, UV filtering, and daily positioning decide the exposure you receive.
Sep 30, 2026
ReadSAD Light Box Buyer's Guide
How to buy a SAD light box that actually delivers light: why lux only counts at a realistic sitting distance, how screen size and UV filtering compare, and what the evidence supports.
Sep 28, 2026
ReadBlue Light Therapy for Seasonal Depression: How It Works and What to Expect
Bright light therapy is a first-line treatment for seasonal affective disorder, backed by decades of controlled trials. The mechanism, the protocol that works, and its limits.
Apr 24, 2026
ReadBlue Light Therapy for Acne: Evidence, Protocols, and Limitations
Blue light kills acne bacteria through a photochemical reaction with porphyrins. What controlled trials show it works for, what it doesn't, and how it compares to standard treatments.
Apr 23, 2026
ReadWhat Is Blue Light Therapy? Mechanisms, Applications, and Evidence
Blue light therapy uses 415–480nm wavelengths for two distinct clinical purposes: killing acne-causing bacteria and regulating circadian rhythms and mood.
Apr 22, 2026
Read