Does blue light really affects sleep?

Does blue light really affects sleep?
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I have recently installed f.lux app on my pc, they say that blue light affects your sleep and your eyes. But after I used this app my eyes feel awful. So is this theory true of just a myth?

Thank you.


Hi, if you just google “blue light sleep” there seems to be enough evidence that it does have an effect. Even googling “blue light sleep myth” didn’t bring anything up. So I think it is save to say that blue light has an effect on your sleep.


thanks @BenGitter:relaxed:


I don’t know if it’s true or not, but my mom sure thinks so… no screens after 9:00…


On an unrelated note, a friend of mine who owns a glasses store told me blue light had a more negative effect of vision.
When I asked why, he told me blue light was one step down from UV. Just me two coins…


My ability to sleep improved after I switched to flux, and I do lots of late night coding.

If your eyes are feeling weird after using it, it could be psychosomatic, or it could be revealing a real issue. If it persists more than a few days, speak to a GP or optometrist :slight_smile:


My phone has a blue light filter which I turn on at night, and I find it more comfortable looking at my phone when the filter is on and the lights are out.


I’ve got a blue light app on my phone (thanks for reminding me to download f.lux too!) and I find it definitely helps. As to whether it’s just a placebo effect or not, there seems to be enough research that says it actually does make a difference.


Thanks… this will help a lot…:smile:


Hi Vivekpasia70,

Blue light affects the sleep, because the blue light inhibits the production of melatonin. Melatonin is a hormone that is permanently produced in the pineal gland. During the day the hormone is produced less and in the night more. This is important for a number of physiological processes in the human body (Martini and Bartholomew, 2012).

The melatonin production can easily be suppressed by light, depending on duration, intensity and wavelength. Blue light has a short wavelength which leads to a greater suppression of melatonin production (Stebelova, Kosnacova and Zeman, 2017).

Sources of blue light are sunlight, artificial light (LED lamps), television, GSM, etc. If the exposure to these sources is reduced, the production of melatonin rises again and gives a signal to the body that one has to prepare for the night. Light is therefore an important response for our circadian rhythm (day- and night rhythm) (Giménez et al., 2014).

If the exposure on blue light in the evening is too big, increase this the change of a wide range of disorders, including sleep disorders, obesity, hypertension, depression, diabetes, etc (Oh et al., 2015).

Late use of computers, television, mobile phones, etc., and even at bedtime, can be detrimental to sleep problems and psychological disorders. In general, a shorter sleep time, a later going to bed, a later awakening time and daytime fatigue are reported in the participants of various sleep studies (Cain and Gradisar, 2010; Ayaki et al., 2016).

Thus, we can conclude that blue light really affects our sleep and it’s better to protect yourself for the possible disorders.

I hope you have enough information with this. If there are any questions, I’d love to hear them!

Kind regards,

Reference list:
Ayaki, M. et al. (2016) ‘Protective effect of blue-light shield eyewear for adults against light pollution from self-luminous devices used at night’, Chronobiology International, 33(1), pp. 134–139. doi: 10.3109/07420528.2015.1119158.

Cain, N. and Gradisar, M. (2010) ‘Electronic media use and sleep in school-aged children and adolescents: A review’, Sleep Medicine, 11(8), pp. 735–742. doi: 10.1016/j.sleep.2010.02.006.

Giménez, M. C. et al. (2014) ‘Effects of a chronic reduction of short-wavelength light input on melatonin and sleep patterns in humans: Evidence for adaptation’, Chronobiology International, 31(5), pp. 690–697. doi: 10.3109/07420528.2014.893242.

Martini, F. H. and Bartholomew, E. F. (2012) Anatomie en Fysiologie: Een Inleiding. Vijfde editie. Amsterdam: Pearson.

Oh, J. H. et al. (2015) ‘Analysis of circadian properties and healthy levels of blue light from smartphones at night’, Scientific Reports, 5(1). doi: 10.1038/srep11325.

Stebelova, K., Kosnacova, J. and Zeman, M. (2017) ‘Intense blue light therapy during the night-time does not suppress the rhythmic melatonin biosynthesis in a young boy’, Endocrine Regulations, 51(1). doi: 10.1515/enr-2017-0004.