How does light therapy work?

Light can support sleep via two complementary pathways:

• Circadian regulation: Short-wavelength light in the blue range (~460–480 nm) is especially effective at influencing melatonin and circadian timing through melanopsin/ipRGC pathways (Brainard et al., 2001; Thapan et al., 2001). Evening room light can delay melatonin onset and shorten its duration (Gooley et al., 2011).

• Photobiomodulation (PBM): Red/near-infrared light (~630–850 nm) interacts with cellular chromophores and can modulate mitochondrial processes at low irradiance (mechanistic overview) (de Freitas & Hamblin, 2016). At night, long-wavelength (red) light can enhance alertness without measurably suppressing melatonin (Figueiro et al., 2020).

Taken together: blue-enriched light in the morning helps anchor the body clock, while dim, short-wavelength-depleted light in the evening supports a melatonin-friendly environment (LeGates et al., 2014; Blume et al., 2019).

Applications for sleep support

Light therapy can help stabilize sleep timing and promote healthier daily rhythms.

Common applications include:

• Morning wake-up routine: Bright/blue-enriched light within ~1 hour after waking supports circadian alignment and morning alertness (Blume et al., 2019; Didikoglu et al., 2023).

• Evening wind-down: Reduce overall brightness and short-wavelength content 1–3 hours before bed; even typical room light can suppress melatonin (Gooley et al., 2011). Children can be especially sensitive (Hartstein et al., 2022). If light is needed at night, long-wavelength/red light can maintain alertness with minimal melatonin impact (Figueiro et al., 2020).

• Shift work or travel: Timed exposure to bright light during the target wake window and darkness during sleep helps adjust the clock (LeGates et al., 2014); expert consensus gives practical day/evening/night targets using melanopic EDI (Brown et al., 2022).

Key benefits at a glance

With appropriate timing/spectrum, light can support:

• More consistent sleep–wake rhythms (Blume et al., 2019)

• Improved morning alertness and reduced sleep inertia (Didikoglu et al., 2023)

• Melatonin-friendly evenings via dimmer, blue-reduced light (Gooley et al., 2011)

• Cellular support mechanisms discussed in PBM literature (de Freitas & Hamblin, 2016)

Who can benefit?

Anyone seeking to improve sleep quality, restore natural rhythms, and feel more rested and energized—particularly those with irregular schedules, shift work, or seasonal disruptions. This page provides general information only.

How to use it in practice

Morning sessions: ~20–30 minutes of bright, blue-enriched light soon after waking to anchor circadian timing (Blume et al., 2019).

Evening relaxation: 1–3 hours before bed, reduce brightness and blue content; if needed, use dim, warm/red light. Red light at night can aid alertness without suppressing melatonin (Figueiro et al., 2020). Note that even low-to-moderate evening light can affect melatonin, especially in children (Hartstein et al., 2022).

Shift/travel adjustments: Align bright light with the new wake phase; keep the sleep phase dark. See expert targets for melanopic EDI (Brown et al., 2022).

Consistency matters—regular exposure patterns help synchronize circadian signals naturally over time.

Scientific context

Action spectra work shows peak sensitivity of melatonin suppression to short wavelengths (~460–480 nm) (Brainard et al., 2001; Thapan et al., 2001). Evening room light can delay melatonin onset and shorten duration (Gooley et al., 2011). Reviews summarize how timing and spectrum shape sleep, alertness and mood (LeGates et al., 2014; Blume et al., 2019).

Some interventional/observational work also reports that red light exposure can support alertness at night without suppressing melatonin (Figueiro et al., 2020) and may relate to improved sleep metrics in athletes (Zhao et al., 2012). These findings are preliminary and context-dependent.

This page describes general mechanisms and applications—without therapeutic or clinical claims for redtreat products.

Why redtreat

Our devices are designed to mirror natural light rhythms—activating options for the morning and melatonin-friendly options for the evening—prioritizing comfort, quality and ease of use.

• Morning: bright/blue-enriched options for the wake phase

• Evening: warm/red options with precise dimming

• Swiss expertise for reliable, consistent use

Disclaimer

The studies referenced on this page are for educational and informational purposes only. They summarize general research on light exposure and sleep regulation and do not constitute therapeutic or clinical claims for redtreat products. Products are not intended to diagnose, treat, cure, or prevent any disease. Individuals with ongoing sleep problems, medical conditions, photosensitivity, or during pregnancy should consult a healthcare professional before use.

Scientific references

• LeGates, T. A., Fernandez, D. C., & Hattar, S. (2014). Light as a central modulator of circadian rhythms, sleep and affect. Nature Reviews Neuroscience.
• Blume, C., Garbazza, C., & Spitschan, M. (2019). Effects of light on human circadian rhythms, sleep and mood. Somnologie.
• Brainard, G. C., et al. (2001). Action spectrum for melatonin regulation in humans. Journal of Neuroscience. (free version: PMC)
• Thapan, K., Arendt, J., & Skene, D. J. (2001). An action spectrum for melatonin suppression. Journal of Physiology.
• Gooley, J. J., et al. (2011). Exposure to room light before bedtime suppresses melatonin onset and shortens duration. J Clin Endocrinol Metab.
• Hartstein, L. E., et al. (2022). High sensitivity of melatonin suppression to evening light in preschool-aged children. Journal of Pineal Research.
• Didikoglu, A. A., et al. (2023). Associations between light exposure and sleep timing and sleepiness in everyday life. PNAS.
• Brown, T. M., et al. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure (melanopic EDI). PLOS Biology.
• de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation. IEEE JSTQE.
• Figueiro, M. G., et al. (2020). Red light at night: alertness without melatonin suppression. Lighting Research & Technology.
• Zhao, J., et al. (2012). Red light and the sleep quality and endurance performance of athletes. Journal of Athletic Training.