Does Red Light Help You Sleep? What the Studies Show
Partly. Red light suppresses melatonin far less than blue light does. In a study of twelve adults, melatonin measured 26.0 pg/ml under red evening light after two hours, against 7.5 pg/ml under blue (Life, April 2025, n = 12). On sleep quality itself, the evidence is thinner than most articles suggest.
01
How many people sleep badly in Switzerland?
Around one third of the Swiss population reported sleep problems in 2022. 27 percent described a moderate disorder and 7 percent a pathological one. The share has risen by 5 percentage points since 1997, with the sharpest increase among women and among people aged 15 to 39. Source: Swiss Federal Statistical Office, Swiss Health Survey 1997 to 2022.
That is the backdrop to a great deal of recent writing about evening light. Some of it is well supported. Some of it is not.
02
Why does blue light suppress melatonin while red light barely does?
The reason is a separate photoreceptor system in the eye, neither rods nor cones. Two independent teams mapped its sensitivity curve in 2001. Brainard and colleagues found peak melatonin suppression at roughly 464 nm (Journal of Neuroscience, 2001). Thapan, Arendt and Skene arrived at a very similar value the same year (The Journal of Physiology, 2001).
Both curves fall away steeply toward the long-wavelength end. Red light at 620 to 690 nm sits around 200 nm from that peak. It is not inert, but it requires orders of magnitude more intensity to produce the same effect.
03
What does the research say about red light and melatonin?
The most direct measurement comes from a University of Zaragoza study published on 28 April 2025 in the journal Life. Twelve healthy adults aged 19 to 55 were exposed to red light (631 nm) or blue light (464 nm) for three hours, from 9pm to midnight. Salivary melatonin was measured hourly by ELISA.
After two hours, melatonin stood at 7.5 pg/ml under blue light and 26.0 pg/ml under red (p = 0.019). Same room, same hour, different wavelength.
An important caveat: this study measures melatonin, not sleep. It says nothing about whether participants subsequently slept better. And with twelve people, it is small.
04
Does red light actually improve sleep quality?
Here the evidence gets thin. The most frequently cited paper is a Chinese study of basketball players published in the Journal of Athletic Training in 2012. Twenty players were split into a red light group and a placebo group (n = 10 each). The red light group received 30 minutes of whole-body irradiation every evening for 14 days. Afterwards their Pittsburgh Sleep Quality Index scores, serum melatonin and endurance performance were significantly better than the placebo group's (Zhao et al., 2012).
Three limitations rarely travel with that citation. The sample is ten people per group. The participants were elite athletes in training camp, not the general population. And the intervention was targeted whole-body irradiation from a therapy device, not a bedside lamp. Those results do not transfer straightforwardly to room lighting.
The honest summary: that red light disturbs melatonin less than blue is well established. That red light actively improves sleep is a plausible but weakly supported hypothesis.
05
What does sleep have to do with skin?
Considerably more than was long assumed. In a study of 60 women aged 30 to 49, good and poor sleepers were compared using the Pittsburgh Sleep Quality Index. Poor sleepers scored higher for intrinsic skin ageing on the validated SCINEXA scale. After controlled disruption of the skin barrier by tape stripping, good sleepers showed 30 percent better barrier recovery at 72 hours (Oyetakin-White et al., Clinical and Experimental Dermatology, 2015, n = 60).
The effect is visible from the outside, too. In a BMJ study, 23 people were photographed once after eight hours of sleep and once after sleep deprivation. 65 untrained observers rated the sleep-deprived photographs as less healthy, less attractive and more tired (Axelsson et al., BMJ, 2010).
06
Red, blue or no light? A comparison
| Light source | Typical range | Distance from the 464 nm peak | Established effect |
|---|---|---|---|
| Screen, cool LED ceiling light | high blue content | very close | melatonin suppression well established |
| Warm incandescent bulb | mixed | moderate | smaller but real effect |
| Red light | 620 to 690 nm | around 200 nm away | markedly less suppression (Life 2025, n = 12) |
| Darkness | no light | not applicable | reference condition |
07
What this means for your bedroom in practice
The choice is rarely light or no light. It is a choice on the wavelength scale. If you need light in the evening, and most people do, the colour of that light changes one variable that measurably tracks with the melatonin curve.
The second point is less comfortable and appears in every study on the subject. Your phone is the strongest blue light source in the bedroom and it sits twenty centimetres from your face. A warm lamp changes nothing while the screen stays on.
08
SOMERA
SOMERA is our red light bedside lamp. It emits between 620 and 690 nm, the range the research above describes as markedly less melatonin-active, around 200 nm from the sensitivity peak. Stepless dimming by twist, 32 sleep sounds, a timer with automatic shut-off, a 2600 mAh battery charged over USB-C and a key lock for a child's room.
It is deliberately built so it can be the last device of the evening rather than another screen. No login, no notifications, no white display at three in the morning.
SOMERA is a wellness and lifestyle product, not a medical device. It is not intended to diagnose, treat or cure any condition. The studies cited were not conducted with SOMERA.
09
Frequently asked questions
Does red light help you fall asleep?
The established effect is indirect. Red light suppresses melatonin far less than blue light. In a study of twelve adults, melatonin measured 26.0 pg/ml under red light and 7.5 pg/ml under blue after two hours (Life, 2025). That does not prove red light actively speeds up falling asleep.
Which wavelength suppresses melatonin most?
Around 464 nm, which is blue light. Brainard and colleagues, and separately Thapan, Arendt and Skene, established this independently in 2001. Sensitivity drops steeply toward the red end of the spectrum.
Can I leave a red light on all night?
There is no evidenced reason to. The research concerns light in the evening, not light during sleep. A timer that switches the lamp off once you are asleep fits the data better.
Does a red light lamp replace an LED mask?
No. An LED mask is a short, targeted session with high light output on the face. A bedside lamp is room light across the whole evening. They do different jobs.
Is a blue light filter on my phone enough?
Night mode shifts the spectrum but does not remove blue entirely, and it changes neither the brightness nor the mental activation caused by the content. In the research on evening light, the screen itself is the larger factor.
10
Sources
- 01Swiss Federal Statistical Office: Swiss Health Survey 1997 to 2022, sleep disorders.
- 02Sanchez-Cano A., Luesma-Bartolomé M. J., Solanas E., Orduna-Hospital E.: Comparative Effects of Red and Blue LED Light on Melatonin Levels During Three-Hour Exposure in Healthy Adults. Life, 2025, 15, 715 (28 April 2025), n = 12.
- 03Brainard G. C. et al.: Action Spectrum for Melatonin Regulation in Humans. Journal of Neuroscience, 2001, 21(16), 6405 to 6412.
- 04Thapan K., Arendt J., Skene D. J.: An action spectrum for melatonin suppression. The Journal of Physiology, 2001, 535, 261 to 267.
- 05Zhao J., Tian Y., Nie J., Xu J., Liu D.: Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players. Journal of Athletic Training, 2012, 47(6), 673 to 678, n = 20.
- 06Oyetakin-White P. et al.: Does poor sleep quality affect skin ageing? Clinical and Experimental Dermatology, 2015, 40(1), 17 to 22, n = 60.
- 07Axelsson J., Sundelin T., Ingre M. et al.: Beauty sleep. BMJ, 2010, 341, c6614, n = 23 photographed, 65 observers.