The Harmful Effects of Smartphone Blue Light

Chances are, you’ve spent pretty much all day staring at screens like the one you’re looking at right now. This highly advanced, beautiful display is designed with very powerful electronic lights that allow developers to present images and videos of any quality for your viewing pleasure.

Several studies are underway to determine the effects of the blue light emitted from smartphones, on your health. From the preliminary results, most experts are anticipating serious repercussions on your health.

What is Blue Light?

Without getting too technical, natural light is composed of ultraviolet, infrared, and visible light rays. Blue light has the highest energy wavelength and is a part of the visible spectrum. In fact, blue light is everywhere, and the natural blue light that we are exposed to in the daytime is beneficial for us.

However, the artificial blue light emitted from digital devices such as smartphones, computers, etc. can be detrimental to health, particularly during nighttime exposure potentially causing damage to your vision, sleep, brain functions, and overall health. The adverse effects appear to be many and are slowly being sorted out in the medical literature.

Adverse Effects of Blue Light

Disturbed sleep schedule

Our bodies follow a natural cycle that allows us to stay awake and alert during the day and helps us sleep at night. However, when you stare at these screens too long and especially before you fall asleep, it affects this natural rhythm, known as the Circadian rhythm.

This leads to a disruption of melatonin production, a hormone that provides your body with the cues for when to sleep. This can make it hard to fall asleep and can completely ruin your sleeping patterns. In turn, prolonged sleep deprivation alone can lead to several serious health issues as described next.

Cognitive impairment

If your sleep is disturbed over a long period of time, it leads to the buildup of neurotoxins, which can result in a vicious cycle making your symptoms worse and worse. Inadequate sleep will eventually affect your cognitive abilities and can affect school/job performance and any situations that require focus.

Memory loss

Sleep rejuvenates and refurbishes brain functions, and a repeated disruption of your sleep cycle will lead to impaired memory function during the day. Disruption in the production of melatonin is the root cause of the disturbance of sleep hygiene.

Impaired immune system

Your immune system produces protective, infection-fighting substances like cytokines while sleeping. Sleep deprivation prevents your immune system from building up cytokines, thus leading to an impaired immune system, thereby making you more prone to contracting infections and falling ill.

Increased risk of diabetes

Diabetes is one of our country’s most serious epidemics. One out of every three Americans will be diabetic by 2020. A Harvard study has potentially shown a novel connection between blue light exposure and diabetes. The disruption to the Circadian rhythm can result in a reduction of leptin levels that can cause an increase in blood sugar levels.


Disruption in melatonin hormone production can also disrupt the functions of the hormones that control hunger. Coupled with poor dietary habits, consumption of highly-processed food with poor nutritional value will ultimately cause obesity.

Increased risk of cancer

Several studies have linked nighttime smartphones usage to some types of breast and prostate cancer. Again the reduced secretion of melatonin causes lower melatonin levels that have been linked to increased cancer risk.

Harms vision

Some studies have shown that constant staring into our smartphones can lead to damage in vision by harming the retina over time by contributing to age-related macular degeneration. Macular degeneration is a common and severe cause of permanent vision loss and blindness. Studies are also being conducted to evaluate the blue light effect on cataract progression. The thought is that staring too long at your smartphone can result in reduced blinking rates, which in turn causes digital eye strain. This kind of strain on the eyes can lead to irritation in the eyes, dry eyes, fuzzy vision, difficulty focusing, headaches, neck and back pain.

Can lead to depression

When your melatonin levels are disrupted or suppressed by blue light, the resultant disruption of your hypothalamo-pituitary axis has been linked to clinical depression.

Summary and Recommendations

Research on the effects of blue light on the human body is emerging and the results are unsettling. Disruption of your melatonin axis appears to be the mechanism of its detrimental effects, and poor sleep is the vehicle by which they manifest in your body.

Fortunately, there are several steps you can take to limit these effects. The most obvious is to abstain from looking at screens after sundown. This can be unrealistic for some in which case the use of blue light filtering glasses can significantly reduce its impact. If that’s not stylish enough for you, many smartphones come equipped with a “night-mode” which programmatically turns off the blue light after dark. Enabling this function is generally a pretty straightforward process and can be found online by a simple web search on the model of your phone with the search terms “blue light filter.” Finally, taking melatonin supplements may also be beneficial in tempering the potentially dangerous effects of blue light.