Blue Light's Unique Effects On Our Health

Make Blue Light Your B****


In 1958, researchers looked at how each unique color affected organisms. R

They found out that blue light could change the circadian rhythm of algae, and this was later found out to be true with humans as well. R

Our understanding about blue light has increased and I have summarized what the literature shows to date.

Blue light is quite powerful and has the power to reset/disrupt our circadian rhythms, but if used and timed properly it may mitigate diseases like diabetes, obesity, depression, anxiety, bulimia, schizophrenia, dementia, and Parkinson's Disease. R R

Some of the reasons (more explained below) are because blue light influences hormone secretion, heart rate, alertness, sleep, body temperature, and gene expression. R

So let's get started.


  1. Basics
  2. How Blue Light Affect The Body
  3. Using Blue Light To Your Advantage
  4. Genetics
  5. Mechanism Of Action
  6. More Research


Light-emitting diodes (LEDs) have been revolutionary for the modern age, allowing us to have visible light at any time of the day (from our TVs, computers, smart phones, tablets, e-readers, etc). R

Most LEDs appears white, but LEDs have a peak emission in the blue light range (400–490 nm). R

Fluorescent light also falls in this category (400–700 nm), producing "white" looking light (as well as UV). R 

How Blue Light Affects The Body

1. Is An Antimicrobial


Blue light is an antimicrobial. R

Blue light can inactivate bacterias and certain viruses such as:

  • A. Baumannii R
  • Candida R
  • E. Coli R
  • E. Faecium R
  • E. Meningoseptica R
  • H. Pylori R
  • Norovirus R
  • P. Acnes R
  • P. Aruginosa R
  • S. Aureus R
  • S. Maltophilia R
  • S. Mutans R
  • Salmonella R

Blue light can also inhibit biofilm formation of bacteria and disrupt bacteria-bacteria communication. R R R

Blue light may be beneficial for deactivating these pathogens on food. R

2. Damages Mitochondria And DNA

Blue light (as well as white light) increases reactive oxygen species (ROS) in cells. R R

Accumulation of too much ROS in a cell can cause damage to the cell, mitochondria, and DNA. R R

For example, night shift workers exposed to blue light may have a higher chance of developing breast cancer. R

Blue light also decreases ATP production in the cell. R

3. Damages The Eyes

Blue light can induce photoreceptor (rods and cones in the eye) damage. R

Photoreceptors are responsible for the ability to "see". R

Blue light also contributes to the development of age-related macular degeneration (AMD). R R

Blue light can also increase the chances of developing glaucoma, especially when mitochondria are damaged in the eye. R R R

Blue light can also damage the cornea and cause "dry" eyes. R

The eye has commensal bacteria that live on the cornea that protect the eye from infection and inflammation. R

Blue light can be used to treat certain bacterial infections in the eye, like infectious keratitis. R

Based purely on speculation of blue light as an antimicrobial, blue light may be contributing directly to inflammation of the eyes and weaken the ocular system's long-term defense against pathogens. 

4. Affects The Skin

In the skin, blue light can decrease the symptoms of psoriasis vulgaris (Pv). R

This is because blue light suppresses the skin's immune system. R

Blue light can also be used to treat atopic dermatitis, neonatal jaundice, and enhance wound healing. R R

Additionally, blue light can be used to treat bacterial forms of acne. R

Blue light has shown to reduce the skin's natural antioxidant levels. R

Blue light exposure from personal devices may contribute to skin cancer, rather than sun exposure. R R

5. Affects Circadian Rhythms


Blue light can reset the circadian rhythm. R

One reason why blue light changes the circadian rhythm is because photoreceptors (such as melanopsin) regulate circadian entrainment, pupil dilation, and other important biologic functions. R

Blue light also induces dopamine release from melanopsin, which may cause dysregulation of dopaminergic neurons. R R

Melanopsin also controls the production and release of melatonin (the hormone that helps with sleep) and gets repaired during the day from sun exposure. R R

Blue light also directly inhibits the production of melatonin. R

Cataracts partially block the ability for photoreceptors to react properly to blue light. R

For example, patients that had cataracts removed (after previously having cataract surgery) were able to sleep better because more blue light could pass through into their eyes during the day. R

Although, there are studies that have shown that in the short term, cataracts can help with sleep, since it is blocking out some of the blue light at night. R

Devices that emit blue light (TVs, phones, laptops, etc) can cause circadian rhythm disruption such as insomnia and mania. R R

These disruptive effects may be diminished by wearing blue-light blocking glasses. R R R R

Proper exposure to blue light that follow circadian rhythm entrainment can reduce the risk of developing cancer. R R

6. Affects Cognition

Blue light can increase alertness. R R

For example, blue light can be used to help with the "post-lunch dip" in energy. R

It can also increase cognition and working memory, but this can decrease over age. R R R

One way blue light increases cognition is by increasing brain derived neurotropic factor (BDNF) and nerve growth factor (NGF), which their elevation is dose dependent on the intensity of blue light. R R

For example, bright light therapy (using blue-green in the morning) helps improve sleep, mood, and cognition in Alzheimer's Disease patients. R R R

Overexposure to blue light may cause brain aging and decreased cognitive function. R R

Chronic exposure may also contribute to neurodegeneration and Parkinson's Disease. R R

Blocking blue light at night can reduce symptoms of Multiple Sclerosis. R

7. Affects Mood

Blue light (such as a bright light device) can been used to treat mood disorders. R

For example, bright light devices have shown to treat seasonal affective disorder (SAD), bipolar disorder, and Postpartum Depression (PPD) as bright light can influence mood (by regulating dopamine). R R R

Blue light combined with caffeine has an even greater effect on elevating mood. R

Blue light at night (even at low, night-light levels) can increase the risk of developing depression. R

8. Affects Hormone Production

As we already discussed, blue light suppresses melatonin production. R

Blue light can change body temperature, heart rate, and hunger levels. R R

For example, blue light can decrease ghrelin (the hunger hormone) and increase leptin (the satiety hormone). R

It can increase the risk of developing heart disease and high blood pressure. R

Blue light can also increase follicle stimulating hormone in women. R

At night, blue light can also raise cortisol and lower alpha-melanocyte stimulating hormone (alpha-MSH). R R

9. Affects Weight


Improper blue light exposure can increase body weight and accelerate the development of metabolic syndrome. R R

Blue light at night increases the production of new fat cells. R

Blue light also changes the metabolism of glucose and increases the risk of developing insulin resistance. R R

Using Blue Light To Your Advantage

Most of the time, you'll want to protect yourself from blue light, but blue light can also be used strategically.

Light's (in general) effects are reliant on dose, duration, timing, and wavelength. R

Biohacking Blue Light


Blue light can be used to:

Protecting Against Blue Light




  • Get more sun and be sure to look around in the sky (not directly at the sun).
  • Minimize blue light exposure (like fluorescents and TVs) when indoors (reduces symptoms of mania and depression). R R
  • Install f.lux or Iris to block out blue light on the computer and install these filters on other devices. R R
  • Install twilight or a similar app on your phone (nightshift for iPhone is insufficient). R R R R
  • Wear blue light blocking glasses when inside and red glasses 1-2 hours before bed. R R R R 
  • Sleep with a sleep mask, cover up or remove lights in the bedroom, and install blackout blinds. R R R
  • The effects of a dark room also applies to babies and children. R

By the way, the colors of this website were chosen primarily because they work with blue light blocking glasses. 😎


Pathways: (May increase neurocognitive disorders)

  • Decreasing BDNF R
  • Inhibit Ccr2 R
  • Inhibit RIP1 and RIP3 R



  • rs4238989 - CC increased risk of breast cancer associated with light exposure R
  • rs3760138 - GG higher risk of breast cancer (40%) with the highest (4 shifts) light exposure at night R


  • rs2278749 - TT reduced risk of breast cancer compared to the other shift workers R
  • rs2290035 - unknown allele, had higher risk of breast cancer R
  • rs969485 - unknown allele, had higher risk of breast cancer R
  • rs3903529 - unknown allele, had higher risk of breast cancer R
  • rs3750420 - unknown allele, had higher risk of breast cancer R


  • rs3749474 - TT reduced risk of breast cancer compared to the other shift workers R
  • rs11133373 - GG increased risk of breast cancer R

OPN4 - influences pupil size under light exposure R R

PER3 - influences non-visual sensitivity to light according to sleep pressure and circadian phase R R R

  • PER3 5/5 allele are particularly sensitive to blue-enriched light R

Mechanism Of Action


  • Blue light acts on IpRGCs (which are not photosensitive).
  • Blue light tells the SCN that it is time to wake up and increases oxidative stress in the eyes.
  • Because of this it causes release of certain hormones and neurotransmitters (like dopamine) to start our internal circadian rhythm.
  • Blue light suppresses melatonin production and increases dopamine release in the brain, but chronic use inhibits the ability for more dopamine to be formed.


  • In cells, blue light can cause cell dysfunction by the photo-excitation of blue light sensitizing chromophores, including flavins, cytochromes and porphyrins, within mitochondria and peroxisomes. R R
  • Blue light negatively effects epithelial cells, pigment epithelial cells, immortalised oral keratinocytes, carcinoma OSC2 cells, fibroblasts, retinal 28 cells, retinal RGC-5 cells, and primary retinal cells. R
  • The human eye lens becomes more yellow (from glutathione-3-hydroxy kynurenine glycoside) with ageing, due to the accumulation of chromophores, particularly in the lens nucleus, which may possibly be a mechanism the body has developed to protect the eye against blue light. R
  • Also in the eye, blue light upregulates CREM-1. R
  • Eyes have 3 main types of photoreceptors: rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) . R
  • Rods and cones are used for image-based vision. R
  • All rods are sensitive to blue light, whereas only some cones are sensitive to blue light. R
  • IpRGCs (split into M1 and M2) regulate circadian entrainment, pupil dilation, and other important biologic functions. R
  • Most M1 cells are found in the suprachiasmatic nucleus (SCN), whereas M1 and M2 cells are closer to equal in number in the hypothalamus. R
  • Interactions between the SCN, the paraventricular nucleus (PVN), the superior cervical ganglion (SCG), and the pineal gland support the neural network of melatonin suppression. R
  • Rhodopsin and opsins (such as melanopsin) are responsible for circadian rhythm entrainment. R R
  • Rhodopsin (λmax 498 nm), the pigment found in the rods of the retina, is extremely sensitive to light and enables vision in low-light conditions. R
  • If rhodopsin is degraded, blue light (even low levels) can cause microglia activation, contributing to neuroinflammation. R
  • In microglia and eyes, blue light increases COX-2, Iba-1, Il-1b, Il-10, Il-6, Igf-1, and Tgfβ. R R R
  • Melanopsin is expressed in retinal ganglion cells (RGCs), which has a peak sensitivity to 459–485 nm and is greatest at ~479nm. R R R
  • Melanopsin signals directly to the SCN, which is the brain's master clock. R
  • RGCs express pituitary adenylate cyclase-activating polypeptide (PACAP) and form the retinohypothalamic tract (RHT), which is responsible for conveying the light information from RGCs to the part of the brain that controls circadian rhythms within the whole body. R
  • Cryptochromes help animals migrate, via (blue-light induced) magnetic field changes. R R
  • Light can induce damage via three mechanisms: photomechanical, photothermal, and photochemical. R
  • Photomechanical damage is due to a rapid increase in the amount of energy captured by the RPE, which may cause irreversible damage to the RPE and lead to photoreceptor damage (dependent on amounts of energy absobed, not spectal composition). R
  • Photothermal damage occurs when the retina and the RPE are exposed to brief (100 ms to 10 s) but intense light that induce a significant increase in the temperature in the tissue. R
  • Photochemical damage occurs when the eyes are exposed to light of high intensity in the visible range. R
  • Lipofuscin, an intracellular age pigment, can protect against light-induced ROS in the RPE cells. R
  • Blue light causes lipofuscin to accumulate in the RPE, which can reduce the amount of nutrients available to the photoreceptors. R
  • In the brain, blue light exposure reduces theta, and low-frequency activity, which are correlates of sleepiness, and can increase alpha waves, which helps with alertness. R
  • It also enhances responses in the left frontal and parietal cortices during a working memory task, while increasing dopamine and hypocretin (orexin). R
  • Light induces neurite outgrowth in an intensity dependent manner. R
  • It increases dopamine acutely but can decrease tyrosine hydroxylase (TH)-positive neurons in the substantia nigra. R R
  • In the anterior cingulate cortex, blue light affects emotion regulation by norepinephrine-mediated increases in learning-related synaptic plasticity. R
  • Consistent blue light decreases heart rate variability and vagal tone. R
  • In the skin, blue light decreases betacarotenoids, while increasing reactive oxygen species (ROS), nitric oxide (NO), and superoxide. R R
  • The cell temperature increased by blue light can increase heat-shock radicals and activate mitochondria. R
  • Blue light also increases expression of NRF2. R R
  • Blue light increases fasting glucose levels. R

More Research

  • If you were blind with damage to your rods and cones, blue light would still have an effect on your circadian rhythm, since melanopsin is a non-visual receptor. R
  • Blue light-filtering IOLs can cause yellow vision in some patients. R
  • Blue light can make it easier to manufacture some drugs. R
  • Blue light stimulates growth of some molds, but inhibits others. R
  • Blue light increases free amino acids and GABA in tomatoes, but decreases glutamic and aspartic acids. R
  • It also reduces the overall growth of tomatoes, cucumbers, and peppers, but not soy. R
  • Blue lasers are very damaging to the eye. R
  • f.lux sleep research R