Blue Light and Melatonin: The Effects of Screen Time on Sleep

Sleep

Two hundred years ago, artificial light didn’t exist. Fast forward to the 1800s, and artificial light became one of humanity’s most significant inventions. Now it’s everywhere—cars, homes, phones, and even satellites in space. But this breakthrough came with a downside: artificial light disrupts our circadian rhythm.

Blue light is particularly problematic. In the morning, it helps regulate our wakefulness and energy, but at night, it suppresses melatonin—the hormone essential for sleep. This evolutionary mismatch tricks your brain into thinking it’s still daytime, disrupting your sleep and overall health.

🔬 What the Science Says

• Blue light exposure within two hours of bedtime can reduce melatonin production by up to 23%, delaying sleep onset.¹

• Regular nighttime screen use is linked to poor sleep quality, increased wakefulness, and difficulty entering deep sleep stages.²

• Teens and young adults are especially vulnerable, as their melatonin production is more sensitive to blue light.³

• Limiting screen time, using blue light-blocking glasses, or reducing blue light on screens can restore melatonin levels and improve sleep quality.⁴

✅ Practical Takeaways

• Reduce Screen Time Before Bed:

  • Avoid screens for at least 1–2 hours (but ideally 3 hours) before bedtime to allow melatonin to rise naturally.

  • Read a book, stretch or do yoga, use a sauna blanket, or meditate instead of scrolling your phone.

• Use Blue Light Filters:

  • Enable night mode or blue light filters on your devices in the evening.

  • Invest in blue light-blocking glasses to minimize exposure.

    • Best tinted ones: Essential Living or Spectra479 (the best on the market, blocking 99.82% of blue light)

    • Best clear ones: Felix Grey

• Create a Sleep-Friendly Environment:

  • Dim the lights in your home an hour before bed to mimic sunset.

  • Keep your bedroom screen-free to avoid late-night temptations.

  • Use blackout curtains to block light from windows.

  • Cover small LED lights on electronics (charger, humidifier, TV, etc.) with electrical tape.

  • Wear a sleep mask for additional protection from ambient light.

  • Use red lightbulbs in bedside lamps and other areas of the house where lights will be on at nighttime. Here are my recommendations:

    • Lightbulbs

    • TrueLight Luna Red Sunset Light (1,000K-3,000K, flicker-free).

    • SuperWarm bulb (1,700K, flicker-free)

    • Neporal amber lights (1,800K, flicker-free). This is what we use in our bedroom.

    • Bedtime Bulb (2,200K, unknown flicker). This is what we use in my kid’s bedroom.

  • Night Lights

    • SerieCozy Red Night Light (800K)

    • Luna Red Light (1,001K, 100% blue light free, 658nm).

    • Emagine A Nightlight (no data listed).

• Balance Screen Time:

  • If evening screen use is unavoidable, take breaks every 20 minutes to reduce prolonged exposure.

  • Use apps like f.lux or built-in device features to shift screen colors to warmer tones.

Live well,

Brian

For a deeper dive, check out my article Ultimate Guide to Lighting: Boost Sleep, Productivity, & Health.

References

1. Chang, A.-M., et al. (2015). "Evening use of light-emitting eReaders negatively affects sleep." Proceedings of the National Academy of Sciences.

2. Chellappa, S. L., et al. (2013). "Light modulation of human melatonin." Journal of Clinical Endocrinology & Metabolism.

3. Nagare, R., et al. (2020). "Blue light exposure and sleep quality in adolescents." Sleep Medicine Reviews.

4. van der Lely, S., et al. (2015). "Blue-blocking glasses as a countermeasure for alerting effects of evening light exposure." Chronobiology International.