Why blue light keeps you awake at night
Comparative Effects of Red and Blue LED Light on Melatonin Levels During Three-Hour Exposure in Healthy Adults
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Red light initially suppresses melatonin just as much as blue light—but recovers within hours.
Most assume red light is inert, but it triggers the same initial suppression. The real difference is recovery—something no consumer product currently highlights.
Practical Takeaways
Switch to red or amber bulbs in your bedroom and bathroom after 8 p.m.—or use apps that shift screen color to deep red (not just 'warm white').
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Red light initially suppresses melatonin just as much as blue light—but recovers within hours.
Most assume red light is inert, but it triggers the same initial suppression. The real difference is recovery—something no consumer product currently highlights.
Practical Takeaways
Switch to red or amber bulbs in your bedroom and bathroom after 8 p.m.—or use apps that shift screen color to deep red (not just 'warm white').
Publication
Journal
Life
Year
2025
Authors
A. Sánchez-Cano, María José Luesma-Bartolomé, Estela Solanas, E. Orduna‐Hospital
Related Content
Claims (6)
Exposure to artificial blue light at night reduces the production of melatonin and prevents the normal nighttime drop in cortisol levels.
Exposure to blue light from LEDs at a specific wavelength and brightness for three hours reduces the hormone melatonin in the saliva of healthy adults, and this reduction lasts longer than when exposed to red light at the same brightness.
Exposure to blue light from LEDs for three hours reduces melatonin levels more than red light in young adults, with melatonin staying low under blue light but recovering under red light.
Exposure to blue light at night reduces melatonin levels more than red light in men, but this effect is not statistically significant in women, even though a similar pattern is seen.
One hour of red LED light at night temporarily lowers melatonin levels similarly to blue light, but melatonin rebounds after two to three hours, suggesting red light may interfere less with the body's natural sleep-wake cycle over time.