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If you’re a skincare device junkie like I am, you may have noticed that the longer wavelengths like red and near infrared have been very popular lately. Blue light, while widely known too, is more utilized for acne which we will be discussing today as well. However, even if your focus is on the prevention of skin aging you’ll still want to tune in as we will be discussing it all – like whether environmental blue light is pro aging.

First up, we’ll be discussing what blue light is, then whether or not it’s damaging to the skin, and any potential benefits including how to select effective devices. If you deal with hyper pigmentation or your skin tone is on the deeper end of the Fitzpatrick scale, I think you’ll find today’s post especially helpful.

So let’s get to the bottom of this topic together.

Visible Light, Oxidative Stress, and Antioxidants

Before we dive into this, I want to really suggest reading my prior posts on red light therapy as well as reactive oxygen species and the skin. In those posts, I cover the visible light spectrum and how light interacts with photoreceptors in the skin. I also cover how free radicals cause oxidative stress and how this impacts the skin in a variety of ways beyond just photoaging. While I will do my best to recap here, my prior posts really lay the foundation for this one and we will be essentially continuing that discussion in addition to covering what blue light is.

What Is Blue Light?

Like red light, blue light is part of the visible spectrum. And of course visible light is actually part of the electromagnetic spectrum with UV radiation and infrared. Blue light falls in the 400 to 495 nm range (with some sources starting at 380 nm), meaning you have high energy, short waves. The lower blue wavelengths are what have stronger antibacterial properties while the higher end will provide deeper penetration into the skin.

Like with red light therapy, photoreceptors in the skin can absorb blue wavelengths. The photopigments housed within these receptors are responsible for absorbing light, made up of proteins called opsin with an attached molecule called a chromophore which absorbs the photons AKA light energy. Each opsin has a specific absorption spectrum so the wavelength used is key and this will come up again later in this post.

Sources of Blue Light

Before we really get into the applications of blue light as well as any potential concerns, it’s important to note that we are exposed to more than one source. Due to the recent marketing and product trends, I think often when I mention blue light many of you will automatically think of the light emitted from phone screens and other devices. There is a lot of debate on whether it’s a cause of concern and I will cover that briefly. However, we are also exposed to visible light anytime we go outside. Blue light from solar radiation has more definitive research showing it to be problematic for our skin and eyes – so that’s what I’m referring to primarily when I discuss harmful effects.

Blue Light and Electronic Devices

This is a controversial subject that I don’t want to get too sidetracked by here as I want to keep the focus on the larger concern – visible light damage via solar radiation – and get into blue light as a treatment room modality and at home treatment. When it comes to sources like electronics, current evidence indicates that the irradiance isn’t high enough to be of concern. Biochemist Michelle from Lab Muffin Beauty Science has an excellent post and video on why this is.

What I will say is that short term yes, evidence suggests it’s safe. However… we don’t know yet in regards to long term exposure and the issue is, it’s very difficult to do these studies on humans. So far, we’ve done them on animals and there are some concerns being raised based on those results.

So ultimately, there is no evidence that blue light from artificial sources is harmful. But please also be aware that more research is needed and that I would just be mindful of your cumulative exposure to blue light via all the sources mentioned till we know more. The science is always evolving as we continue to research and learn and luckily, both topical and endogenous antioxidants appear to do a good job mitigating damaging effects regardless.

The rest of this blog post will be referencing high energy visible light (HEV) from the sun as well as blue light used in skincare devices.

Visible Light from the Sun

Before we get into blue light and it’s applications for skin in dermatology and other related fields, I think it’s important to understand the potential risks. Like with red light therapy, reactive oxygen species are generated when skin is exposed to blue light and oxidative stress results. Unlike red light though, blue light waves are very high energy which means greater potential for damage. This is especially true when discussing the high levels we’re exposed to from the sun and again – that’s primarily the source where you’re going to see the harmful effects I’ll be covering next.

Harmful Effects of Blue Light

Current research is still in the preliminary stages but does suggest that blue light from solar radiation is similar to UV rays in that it generates free radicals, oxidizes antioxidant defenses, and is also responsible for aging in the skin. This same study recommends using a sunscreen that can absorb blue wavelengths for this reason.

Tip: look for polysilicone-15 in your sunscreen formulations to start, it can not only help stabilize the more unstable sunscreen agents but can absorb blue wavelengths. I like this one from Kose.

Another study irradiated a small group of volunteers with various wavelengths from the blue light spectrum and found that endogenous antioxidants were depleted, suggesting that ROS was generated and the overall response was almost identical to UV radiation. Also of interest is that while red light therapy was shown to accelerate skin barrier recovery, blue light delayed it.

Please note, I’m focusing primarily on research using actual live skin as much as possible as skin cells in a petri dish will never respond the way intact, living skin will. In vitro studies can be helpful to further elucidate the mechanism of action behind processes but should never be the foundation of your research. Any pure substance can be damaging to isolated cells for example, including water, so it can provide misleading information if that’s the sole basis of your argument.

For example:

“Through a reporter assay for per1 transcription, we demonstrate that blue light at 410 nm decreases per1 transcription in keratinocytes, showing that epidermal skin cells can sense light directly and control their own clock gene expression. This triggers cells to “think” it is daytime even at nighttime. Elsewhere, we measured different skin cell damage because of blue light exposure (at different doses and times of exposure) vs. cells that were kept in full darkness. We show an increase in ROS production, DNA damage and inflammatory mediators. These deleterious effects can potentially increase overall skin damage over time and ultimately accelerates ageing.” Source

The above is helpful in addition to the other research done but doesn’t mean very much by itself and I think it’s important to just stress that we should look at the full picture, not individual pieces of evidence.

Along the same lines as above, one study using isolated human dendtritic cells found that while blue light irradiation didn’t cause cell death like UV exposure it did suppress their activation and is allogeneic stimulatory potential. And another study on dermal fibroblasts found that they were impacted depending on dose and wavelength. While only 410 and 420nm led to oxidative stress, all wavelengths studied including 453 nm reduced antioxidant capacity of fibroblasts and reduced proliferation.

In addition to research on blue light and its effects on both intact skin and skin cells, concerns over long term hazards of neonatal blue light therapy have been raised. We also know that blue rays, like violet ones, are highly damaging to the eyes. In fact, the research there is much more extensive than what we have on skin. However, that’s not the focus of this post so if you’re interested please research more on your own.

And lastly, we have animal studies. Conclusions from research done on animals can’t always be applied directly to humans but since it can be difficult to do research on humans, especially when there is a real risk of harm, sometimes it’s the best we have. There is a significant amount of testing done on animals showing blue light is harmful, from studies on rat gingival tissue indicating we may need to be careful when using blue wavelengths for teeth bleaching to researching on blue light irradiation of somatic cells from monkeys being shown to cause DNA damage due to ROS and how antioxidants can help.

To summarize the above, preliminary research done on human skin and eyes, isolated cells, and animals indicate that blue wavelengths from solar radiation can cause oxidative stress and be harmful in high doses similar to UV rays but more research is nonetheless needed.

Blue Rays and Melanocytes

If you are darker than a Fitzpatrick III and/or deal with hyper pigmentation then blue light will be something even more relevant to you. In my blog post on reactive oxygen species and oxidative stress, I touched on how melanocytes are especially susceptible to damage from reactive oxygen species. This is true still and then research indicates that melanocytes interact with blue light as well.

Remember how we discussed opsin at the start of this post? This fascinating article discusses how melanocytes actually sense blue light and regulate pigmentation through Opsin-3. And it’s “mainly formed in dark-skinned melanocytes and induces a sustained tyrosinase activity, thus explaining the long-lasting hyperpigmentation that is observed only in skin type III and higher after blue light irradiation.”

What does this mean? Blue light directly stimulates pigment formation (melanogenesis) by acting on melanocytes thanks to Opsin-3. Now, this is actually a protective measure against the damaging effects of blue light so I want to stress that this is your skin protecting itself. But that’s a small consolation for those dealing with stubborn hyper pigmentation.

Due to the above, it should be no surprise that iron oxides (which protect against visible light) and antioxidants (which can neutralize ROS generated by light) have been shown to decrease melasma relapse rates.

One study found that “iron-oxide containing formulations significantly protected against visible light-induced pigmentation compared to untreated skin or mineral SPF 50+ sunscreen in Fitzpatrick IV individuals.”

More information here.

And if you don’t deal with hyper-pigmentation or you’re Fitzpatrick II and below, these formulations are still helpful:

“Ultraviolet (UV) radiation is a main cause of aging of sun‐exposed skin, but greater attention is being focused on the damaging effects of high‐energy visible (HEV) light (400 and 500 nm). 

Sunscreens formulated with iron oxides provide enhanced protection against blue light, especially when combined with zinc oxide.”
Source

If you’re in need of a sunscreen formulation that fits the above criteria, ISDIN sells my favorite mine real sunscreen for normal to dry skin while MDSolarSciences has a great one for combo to oily skin and you can get it 20% off with code MIRA20.

Blue Light in Photobiomodulation

Safety for Aesthetic Use

I know what you may be thinking: Is it even worth using blue light in LED masks and lamps?

Luckily, short term exposure to blue light has been shown to likely be safe. And when it comes to skin benefits and harm, it’s all about wavelength and irradiance in addition to exposure time. However, safe does not mean without side effects and I would consider carefully if you’re the right candidate.

To quote one study, “Blue light has both positive and negative effects on the skin.”

Another study on its safety in a dermatology setting when used short term found it to be safe. It should be noted though that it was only used for 5 consecutive days and the sample size was only 8 patients. In those 5 days, the blue light irradiation did not cause DNA damage or early photoaging but they noted that “the biological effects of blue light on normal skin are transient melanogenesis and inexplicable vacuolization without resulting apoptosis.”

So while they did conclude it was safe (a bit prematurely in my opinion), there were some side effects in this small study and that doesn’t mean DNA damage and photoaging won’t occur over time.

I’m not saying don’t use blue light, make sure you’re not someone more at risk to it and I would keep treatments targeted and brief. And don’t forget the antioxidants! Like with red light, they can neutralize the ROS generated. I love the Maysama Green Rooibos Pressed Serum (code MIRA10 to save 10%) for dry skin and it can be used as a recovery serum after treatments too. Or shop my other favorites for photobiomodulation like the Isntree Fresh Green Tea toner, a longtime favorite.

Benefits of Blue Light

Interestingly enough, it’s the reactive oxidative species generated that are likely responsible for its antibacterial action and benefit for acne prone skin. And this is who I recommend blue light therapy for.

ROS levels are most strongly attributed to the 400-420nm range and this is where the antibacterial action of BLT (btw- it’s late at night when I’m writing this and this acronym totally made me giggle) for acne has been proven. 405 nm is the ideal wavelength but 415 nm has also been studied and shown that be effective. This is very important when selecting a blue light device.

As far as how it works, it’s believed that “light is absorbed by porphyrins produced naturally within sebaceous follicles by P. acnes” and that the “415 nm wavelength within the blue light spectrum is most effectively absorbed.”

This is what then results in ROS generation: “Light absorption leads to photo-excitation of porphyrins and subsequent release of singlet oxygen and reactive free radicals that exert bactericidal effects on P. acnes.”

Read more here.

When selecting a device or lamp with blue light, it’s important to select something with the wavelengths mentioned above and with a strong enough output to match the irradiance used in the studies on blue light acne. And please remember that unlike red light, blue light therapy is unsafe for the eyes and eye protection is needed!

Note: I’ve turned many of you into the Wolezek Red/NIR lamp this last year, which you can find in my Red Light Therapy Starter Kit. However, the blue light options from Wolezek and other Amazon lamps unfortunately are in the 450-460 nm range and I do not recommend these personally and won’t be testing them. I don’t want anyone to think those are included in my recommendation as I know I wasn’t clear enough in our Facebook group originally when I discussed testing out the Hooga a few months back. Sorry for any confusion, I continue to learn myself at the end of the day.

Only pulsed 450 nm light has evidence for acne from what I can find and it’s a single study while the many other studies on acne utilize the shorter wavelengths and stress its importance. The pulsed light was used to overcome the shortcomings of longer wavelengths but even then, isn’t enough in the face of the larger body of research showing you need 405-415 nm in my opinion.

That being said, if you do have acne then red light therapy pairs beautifully with 405-415 nm blue light. While the BLT targets the bacterial aspect of acne, RLT can help with its anti inflammatory and wound healing benefits. Red light may also directly target sebaceous glands.

For this reason, I ordered this one to test out since it’s 415 nm, looks to have good output, and has red 660 nm as well. I’ll update you all with my thoughts, as always, and will continue to look for effective blue light options.

Speaking of the bacterial aspect, blue light has antimicrobial effects that extend beyond acne. Blue wavelengths can suppress biofilm formation for example and in high irradiance dosages display a broad-spectrum antimicrobial effect against Gram-positive and Gram-negative bacteria.

Here is also where 450-460nm regular blue light has actually been shown to work but until it’s been proven for acne, I don’t personally feel comfortable suggesting it. But for sanitizing surfaces and other applications, I’m all for it.

What’s the Takeaway?

If you got through all that, I appreciate you sticking to the end. And I suspect a final conclusion is needed.

I’m running out of steam so we’re doing… bullet points. Yup.

• UV rays aren’t the only damaging form of visible light
• Deeper skin tones and those with hyper pigmentation especially should be careful with blue light
• Typical sunscreen formulations don’t protect against visible light, only UV rays, so look for mineral options with iron oxides and antioxidants
• Blue light can have cosmetic and therapeutic effects but should be used for specific concerns like acne and not long term to minimize risk – provided you’re not someone more at risk of adverse effects
• 405-415 nm and high powered devices are what are mainly proven to work for acne and what I would look for
• While blue light from electronics have not been shown to have a high enough irradiance to be harmful short term, we don’t know long term effects and there are other sources of blue light so keeping overall exposure low is likely prudent

If you got to the end, do you use a blue light or are you more a fan of red and NIR wavelengths? Which device do you own? As always, thank you all for reading.