In a modern world dominated by screens and artificial illumination, blue light has become a hot topic in health and well-being discussions.

But whereas most conventional wisdom says all blue light is bad for you—responsible for everything from eye strain to sleep disruption—the right kind of blue light is an absolutely vital part of the light spectrum. Blue light itself is present in high amounts in natural sunlight! 

So, is blue light as bad as it's made out to be? Let's explore the world of blue light further and uncover the facts you need to know.

What is blue light?

Blue light is the shortest and most energetic wavelength of visible light. It plays a crucial role in regulating our circadian rhythm and keeping us alert and well during the day.

It's in high amounts in natural sunlight during the daytime and is critical for all human, plant, and animal life. 

However, excessive exposure to blue light, especially at night, can disrupt sleep and lead to other health problems.

Is blue light bad for you?

Contrary to popular belief, blue light is not inherently bad. As we just mentioned, it's present in high amounts in natural sunlight during the daytime and is critical for all human, plant, and animal life. 

Getting a dose of blue light in the morning can help signal your brain that it's time to wake up, boosting alertness and mood. However, the type and timing of blue light exposure is critical: while it's beneficial during the daytime, too much blue light at night can interfere with our sleep patterns and overall well-being.

Why we need blue light + how blue light affects us

As we've alluded, blue light regulates our body's internal clock and processes. 

Blue light affects melatonin production, best known as the hormone regulating sleep.

When the eyes are exposed to blue light, a signal is sent to the brain's suprachiasmatic nucleus (SCN), which regulates the body's internal clock. 

This signal suppresses the production of melatonin, which can help increase alertness and reset the body's circadian rhythm to be more awake and active during the day.

Conversely, when blue light exposure decreases, such as in the evening or at night, the production of melatonin increases, which signals to the body that it's time to sleep. 

This is why it's important to limit exposure to blue light at night, particularly from electronic devices like smartphones and computers, as this can disrupt the production of melatonin and interfere with the body's natural sleep-wake cycles.

Different types of blue light

Blue light can be divided into two main categories: blue-violet and blue-turquoise light. It is either present in isolation (the worst) or as a full spectrum (the best) containing both types of blue light—blue-violet and blue-turquoise—in a full and balanced spectrum. 

As we'll soon see, shorter wavelength, high-energy blue-violet light is considered more harmful (especially for our eye health), while blue-turquoise light is the "healthy" blue light essential for optimal body and mind functioning. 

Blue-violet light

The blue–violet (380 to 450 nm) portion of the spectrum is also known as high-energy violet (HEV) or high-energy blue light. Most of what you hear about the dangers of LED lighting involve this specific part of the blue light spectrum: Blue-violet light reaches the retina of the eye and has been shown to cause cumulative and lasting damage to retinal structures [15–17]. In particular, it causes oxidative stress that leads to the destruction of photoreceptor cells. 

Blue-turquoise light

The blue–turquoise (450 to 500 nm) portion of the spectrum is the "healthier" type of blue light. Blue-turquoise light—specifically 480nm—is the strongest influencer of our circadian rhythm and the production or inhibition of melatonin, a hormone most well-known for its role in inducing sleepiness. 

We've written extensively before on how blue light affects our circadian rhythm. You'll note that the most important factor in this process is the presence of highly specialized, non-image-forming photoreceptors in our retinas, called intrinsically photosensitive retinal ganglion cells. These cells contain a photopigment called melanopsin, whose peak absorption is 480nm blue light.

Full spectrum blue light vs. isolated blue light

You've likely heard about the dangers of blue light in LED bulbs: they cause cataracts and will speed up the effect of macular degeneration. While some studies show this to be true, it's important to note that those studies were on standard cool white LED with a spike in blue-violet light at 380 nm or so. Today, there are varieties of full spectrum LED lights, including blue light - blue-violet and blue-turquoise - in a full and balanced spectrum.

Tips for healthy blue light exposure: the right way to use blue light

As we've learned, blue light can be absolutely crucial, beneficial, yet harmful at the same time. It all depends on the timing and intensity of exposure to the light. 

Here are some tips for using blue light in a healthy way:

Morning and daytime:

Get your blue light exposure in the morning/daytime: Whether you're getting outside first thing in the morning or turning on some bright white overhead lights, exposure to blue light in the morning can help reset your circadian rhythm and improve your alertness and mood. 

Evening and nighttime:

Limit exposure to blue light in the evening, especially in the hours leading up to bedtime. You can try using software or apps that filter out blue light from electronic devices and use dimmer, warmer-colored lights in your home at night. Some great options would be warm white LED bulbs or, for those LED-averse, the following low-wattage incandescent bulbs. 

Incandescent bulbs naturally have a lower, warmer color temperature with essentially zero blue light. 

Take breaks from devices/set your screens to warm: 

Be sure to give your eyes plenty of rest when using electronic devices such as smartphones, tablets, or computers.  

We also recommend adjusting your display's brightness and color temperature to a warm white setting. 

iPhone Hack: How to turn your screen red at night 

How can you safely use your phone at night without the danger of blue light delaying or disrupting your sleep?

The answer: turning our phone screens red at night to eliminate the blue and green light emitted. 

As soon as it gets dark outside, we recommend switching your screen to be as warm (or completely red!) as tolerable. Once you're about an hour or so away from bedtime, however, it is advisable to completely eliminate blue light from devices and turn your iPhone screen red. 

Learn how to switch your iPhone screen to turn red at night.

The relationship between color temperature and blue light 

Now that we better understand the types of blue light, you'll want to know how to determine which light bulb may emit which types of blue light! 

Knowing a light bulb's color temperature can tell you a lot about its spectrum and whether or not there's blue light present. 

Color temperature, measured in Kelvin (K), describes the warmth or coolness of light emitted by a source. Higher color temperatures, like those of daylight or cool white LEDs and sunlight at high noon, contain more blue light, whereas warmer color temperatures of light (think 3000K and below) have little blue light in their spectrum and more red light.

We find this helpful when choosing light bulbs, but it also gives us a more thorough understanding of light in general. 

What Light Bulbs have Blue light?

Any light bulb with a cooler color temperature will contain blue light. This means natural white to daylight color temperature LEDs, fluorescent tubes, CFL bulbs, and any other light source with a high color temperature will contain blue light. To know precisely which type of blue light it is, a spectrometer (to see the visible light spectrum in a graph) will be required. 

By definition, incandescent light bulbs produce virtually no blue light. In contrast, their brighter cousin, the halogen incandescent, produces a small amount of full-spectrum blue light (a balanced distribution of both blue-violet and blue-turquoise light).

Remember again that not all blue light is bad, and we usually have to worry only about unnatural blue light spikes present in most generic cool white or daylight-white LED light bulbs. Choosing either a full spectrum LED or an incandescent or halogen light bulb will ensure you're getting "safe" doses of blue light in its full spectrum—as nature intended—and not some fragmented, isolated light. 

What are the best low blue light light bulbs?

As we just mentioned, incandescent light bulbs produce virtually no blue light, and warm white color temperature LEDs (below 3000K) also produce little blue light. 

Red light bulbs, of course, have no blue light (or any other color present). 

As a rule, we tend to prefer the analog light of incandescence over LED. Many people find a palpable difference to the "feel" of the two different lights: analog filament light emits invisible infrared energy and is most similar to natural sunlight (beautiful full spectrum LED bulbs exist, but we find them to feel a bit stark and lacking in ambiance). For this reason, we always recommend Chromalux® full spectrum incandescent or warm white LED bulbs - Chromalux® incorporates the element neodymium in their glass to purify the visible light spectrum uniquely to more accurately represent the color saturation and contrast present under natural sunlight. 

Wrapping up.. 

Takeaway: The type and timing of blue light is essential. 

In today's screen-centric world, blue light has become a hot topic in discussions about health. While it's often portrayed as harmful, it's crucial to understand that not all blue light is bad. Natural sunlight, rich in blue light, is essential for regulating our body clocks and overall well-being. By being mindful of when and how we're exposed to blue light (along with the types of blue light), we can enjoy its benefits while minimizing any potential negative impacts, ensuring a healthier relationship with the light around us.

Until next time, be well and well-lit!