A few staples in every aesthetic morning routine on Instagram: a plush white robe, a perfectly poured matcha latte, and, lately, the red glow from an LED mask. These masks have made their way into every skincare routine on your feed - and even onto celeb faces like Kim K - promising smoother skin, fewer breakouts, and a collagen boost, no esti visit required. But before you drop $300 to look like Michael Myers with a skincare habit, let’s get into it: is there any science behind LED masks?

The Science Behind Light and Our Skin

The concept of simply shining light on our skin instead of applying a serum sounds futuristic - and maybe even far-fetched. But surprisingly, there is solid science explaining how and why it works.

We can see because our eyes contain photoreceptors called rods and cones, which absorb light, triggering a reaction that converts it into an electrical signal sent to the brain. Within these receptors, light-absorbing molecules - called chromophores - allow us to see light. These molecules are bound to proteins called opsins, which fine-tune which wavelengths of light can be absorbed. Together, chromophores and opsins help convert photons into the electrical signals that are sent out through the synaptic ending of the receptor. 

But the skin is different. It doesn’t “see,” so there’s no need for photoreceptors. Instead, skin cells are equipped with photoreceptive proteins that respond to light. Essentially, parts of the light-absorbing machinery from photoreceptors are embedded in skin cells.

How Light Interacts with Skin

Light interacts with our skin in a variety of ways - especially when it comes to appearance and how our eyes perceive it. Light reflects, scatters, and absorbs as it interacts with the skin’s surface and deeper layers. 

• Reflection: Light reflects off the surface, a phenomenon more pronounced in oily skin types. Texture and flaky skin affect how light is reflected.
  
  

• Scattering: Light can scatter as it enters deeper layers, particularly when interacting with collagen, creating a diffused glow.
  
  

• Absorption: Molecules in the skin, such as melanin and hemoglobin, absorb certain wavelengths of light, influencing the color we perceive.
  
  

The science behind light is highly complex and focusing on the practical applications to skincare can help simplify. Understanding how light interacts with the skin can guide us in our skincare choices, including leveraging light-based treatment modalities like LED masks.

Skin Appearance and Light

Youthful skin allows light to penetrate deeper layers, creating that “lit from within” glow. To achieve this, keep your skin hydrated, and use retinoids to improve collagen quality, helping light scatter evenly for that smooth, glowing look.

Youthful skin has more penetration of light into the deeper layers rather than the skin surface (think of the saying “lit from within glow”). While no one can turn back time, keeping the skin hydrated can provide a similar effect. Retinoids also improve collagen quality so light is more evenly scattered.

Light Absorption and Skin Health

Sunlight contains a spectrum of light. Red light is also absorbed and triggers beneficial cellular processes but isn’t enough to offset the damaging effects of UV rays. The skin is able to cope with some UV radiation by absorbing it but only sunscreen can protect against high levels. LED devices provide the beneficial wavelengths without the damaging ones.

1. The Benefits of Different Wavelengths of Light

7 color LED masks are all the rage, they’re at the top of the search if you look for red light therapy devices like masks on Amazon. But only red, blue, and near-infrared light have compelling evidence behind them for skin. Light falls within the electromagnetic spectrum, with shorter wavelengths being more powerful and potentially damaging (e.g., gamma rays, x-rays). Visible light, including the wavelengths used in LED masks, falls in the middle of the spectrum.

Ultraviolet Light

UV light is absorbed by our DNA, causing potential damage. UV-B is particularly harmful, while UV-A penetrates deeper, causing indirect DNA damage via oxidative stress. Though UV light has medical applications (like treating certain skin disorders), safer options are usually preferred for skincare.

Blue Light

Blue light, with its high energy, can generate reactive oxygen species (ROS), contributing to oxidative stress and hyperpigmentation in darker skin tones. However, it requires significant energy to trigger these effects, so don’t worry about blue light from screens - sunlight and overuse of high-powered devices are the concern2. 

Benefits: Blue light is antibacterial as a result of its absorption by bacterial porphyrins, generating reactive oxygen species (ROS) that reduce acne causing bacteria. Low levels of ROS also help stimulate various cellular processes involved in wound healing for faster repair.

Red Light

Red light is among the most studied wavelengths for skin health, with benefits ranging from muscle recovery to skin health. Its primary target is cytochrome C oxidase, an enzyme in mitochondria involved in cellular energy production. 

Red light is believed to trigger ATP production, generating more energy for our cells. This includes mitochondria in fibroblasts, resulting in more collagen production, and in the skin’s stem cells for better repair. Red light also reduces inflammation by helping to regulate immune cells.

Benefits: Red light supports skin regeneration and reduces inflammation, making it highly effective for anti-aging and skin repair.

Near Infrared  

While not as extensively studied as red light, NIR works similarly but at a deeper level. It penetrates deeper into the tissues, helping with inflammation reduction and wound healing. Because it’s absorbed by water molecules and hemoglobin, it can feel a little warm.

Benefits: NIR light enhances skin regeneration and reduces deeper tissue inflammation.

1. Devices and Treatment Protocols

Photobiomodulation (PBM) is the use of light to stimulate cellular processes and benefit the body (including skin). Whether you’ve been swayed by the science or an influencer in your feed, deciding to purchase a device inevitably just leads to more questions like:

• Should I use a mask, panel, or handheld device?
  
  

• How long should I use it for?
  
  

• What distance should I keep from my face?
  
  

• Should I use it before or after my skincare routine?
  
  

Here’s what you need to know when shopping:

Wavelengths

• Red Light: 620-630 nm, 660-670 nm

• Near-Infrared: 800-850 nm (ideal range: 820-830 nm)

• Blue Light: 405-415 nm
  

For red and NIR, these wavelengths roughly coincide with the absorption peaks of cytochrome c oxidase. While 620 nm and 670 nm are closest to this, anything within this range will work. Light-emitting diodes (LEDs) have replaced low-level laser for photobiomodulation and 630 nm and 660 nm are easier to manufacture while remaining researched. 

Amount of Energy

The amount of light energy per treatment is measured in joules/cm2. Red light therapy works best with a light energy dose between 3-9 Joules per treatment. Too little won’t trigger a response, while too much and you’ll see decreasing results (called the biphasic dose response, likely from too many reactive oxides species generated).

Rate of Energy

The energy delivered is also affected by the irradiance (the rate of energy delivery). Close contact increases irradiance, but a wider beam from a distance provides more even coverage. Keep this in mind to adjust treatment time and ensure optimal results.

Treatment Time

There’s a simple equation that you can use to confirm the treatment time given by the brand.. You’ll want to ask the brand for the irradiance at the distance the diodes are from your skin during treatment. Distance is key as some brands just share the irradiance right at the surface of the light which will be much higher.

Irradiance on mW/cm2 x Time (in seconds) x 0.001 = Joules per treatment 

Example: A panel’s output is 50 mw/cm2 when used 12 inches from the face. I have been following the directions from the brand and using it for 5 minutes (300 seconds) and want to make sure this isn’t too high. So I multiply 50 by 300 then times .001, getting 15 Joules per treatment.

Device Options

When it comes to devices for photobiomodulation, panels, lamps, and masks are the most popular options. Each offers unique benefits depending on your needs:

• Lamps are typically the most affordable, often just requiring the purchase of the bulb. They provide a wide beam that can treat the face and other areas of the body.
  

• Panels are ideal for those wanting to treat more than just the face and are usually the most powerful option.
  

• LED masks offer unmatched convenience, making them easy to use at home for facial treatments.
  

If you’re looking for device recommendations, check out creators like Goals to Get Glowing, who compared over 60 LED masks, or Alex Fergus, known for his in-depth panel reviews.

How To Use Your LED Device for Maximum Results

After you’ve gone through the headache of deciding which device to buy, it’s time to put it to use. You don’t want it to collect dust on your shelf or become a fancy paper weight

1. Blue Light for Breakouts: Use blue light as needed for acne. It’s your “emergency treatment.”
   
   

2. Red Light for All Skin Types: Most people benefit from red light therapy. For enhanced results, pair with near-infrared (NIR) light, unless you have heat-sensitive conditions like rosacea or melasma.
   
   

3. Follow Treatment Instructions: Double-check the recommended treatment time and distance from your face. This info is usually included with your device, but always confirm with the equation above.
   
   

4. Prep Your Skin: Cleanse your face, then apply a hydrating, antioxidant serum. We’ll discuss more in the next section but a serum, like Stratia’s Rewind, will allow for better penetration of light into the skin. Antioxidants help protect the skin and make the biphasic dose response less of a concern.

5. Serum Absorption: Let your serum fully absorb - 5 minutes for dry skin, more for oily skin - before starting your treatment to minimize light reflection at the skin surface.
   
   

6. Post-Treatment Skincare: Follow your usual routine after the session. Aim for 3-5 sessions per week for consistent results.
   
   

Speed Up Results

Want faster skin improvements? Combine red light therapy with microneedling, chemical peels, or laser treatments. Since red light works subtly over time, pairing with these micro-injury treatments can enhance results.

4. Debunking Common LED Myths

1. Why not just go outside and get sunlight for free?

While sunlight does contain visible light, it also includes harmful UV radiation and high-energy blue light. While outdoor time (with sun protection) is beneficial, photobiomodulation provides a focused treatment with only the beneficial wavelengths, avoiding the risks of UV exposure.

2. Do LED treatments damage your eyes?

Blue light can potentially damage the eyes, so eye protection is recommended when using blue light therapy. However, red light therapy has been shown in studies to improve eye health. As this topic falls outside skincare, consult your provider before using LED treatments near your eyes.

3. Can red light therapy cause fat loss?

Red light therapy has been explored for weight loss, leading to concerns about facial volume loss. The therapy may reduce body circumference by prompting fat cells (adipocytes) to release triglycerides. This effect is temporary and observed mainly in areas where the body stores fat, not the face. 

1. Is it true that red light can worsen hyper-pigmentation?

Red light can potentially exacerbate melasma, a pigmentary disorder triggered by heat. Typically, near-infrared (NIR) light, which generates more heat, is the main concern. However, some individuals may be more sensitive to heat, and higher irradiance could contribute to melasma flare-ups. Always consult with your provider if you have concerns.

2. Are LED masks effective?

Although LED masks have long been considered weak within the RLT community, many now meet the specifications supported by research. Some argue that the close proximity of LEDs to the face can lead to uneven treatment, but science communicator Michelle Wong refutes this, citing a study on wound healing where the surrounding tissue saw improvement. Ultimately, choose a device that fits your needs and supports consistent use.

3. Does skincare block light?

Skincare products, including moisturizers, do not block light. Otherwise, we wouldn’t need dedicated sunscreens. UV filters in sunscreens absorb UV radiation, similar to how chromophores in the skin absorb light. Iron oxides can also help protect darker skin tones by absorbing blue light as well. Aside from these ingredients - which act as a physical shield - skincare isn’t going to block light from entering the skin.

For light-based therapies, I have been recommending pre-treating the skin for years. Hydration actually allows for better penetration of light, as discussed at the start. While not quite the same application, hyaluronic acid and glycerin are used even as optical clearing agents for light based microscopes because they reduce light scatter and allow deeper skin structures to be visualized. Additionally, antioxidants in the serum help balance the reactive oxygen species (ROS) generated during photobiomodulation, ensuring optimal efficacy without overstimulation.

Summary

In short, red light therapy and light-based treatments are backed by solid science, and there are key specifications to consider when choosing a device. Proper usage is also more involved than it might seem. If you found this guide helpful, be sure to bookmark it so you can refer back.

I also want to highlight Ari Whitten’s PDF guide to red light therapy dosing - an invaluable resource that has helped me and countless others beginning their red light journey over the years.

References

1. Herrera, M. A., , A. P., da Costa, P. E., & Baptista, M. S. (2024). Red-light photons on skin cells and the mechanism of photobiomodulation. Frontiers in Photonics, 5, Article 1460722. https://doi.org/10.3389/fphot.2024.1460722

2. Kuse, Y., Ogawa, K., Tsuruma, K., Shimazawa, M., & Hara, H. (2021). Dosimetry assessment of potential hazard from visible light, especially blue light, to the eye and skin. Clinical, Cosmetic and Investigational Dermatology, 14, 283–292. https://doi.org/10.2147/CCID.S295902

3. Matei, N., Heredea, R., Măruțescu, L., Țieranu, E., Oancea, A., Vasilovici, A., & Avino, A. (2024). Unlocking the power of light on the skin: A comprehensive review on photobiomodulation. International Journal of Molecular Sciences, 25(8), 4483. https://doi.org/10.3390/ijms25084483

4. Ravanat, J.-L., Douki, T., & Cadet, J. (2001). Direct and indirect effects of UV radiation on DNA and its components. Journal of Photochemistry and Photobiology B: Biology, 63(1–3), 88–102. https://doi.org/10.1016/S1011-1344(01)00206-8

5. Regazzetti, C., Sormani, L., Debayle, D., Bernerd, F., Tulic, M. K., De Donatis, G. M., et al. (2018). Melanocytes sense blue light and regulate pigmentation through Opsin-3. Journal of Investigative Dermatology, 138(1), 171–178. https://doi.org/10.1016/j.jid.2017.07.833

6. Smith, D. J. M. (2024). Photoreception and phototransduction in human skin. Medical Research Archives, 12(6). https://doi.org/10.18103/mra.v1216.5366

7. Suh, S., Choi, E. H., & Atanaskova Mesinkovska, N. (2020). The expression of opsins in the human skin and its implications for photobiomodulation: A Systematic Review. Photodermatology, photoimmunology & photomedicine, 36(5), 329–338. https://doi.org/10.1111/phpp.12578

Zhang, Z., Liu, S., Chen, Y., Yang, Z., Xu, Y., & Zhang, L. (2023). The role of photobiomodulation in cellular responses and its potential in the treatment of human diseases. Antioxidants, 12(3), 766. https://doi.org/10.3390/antiox12030766

Mira is a skincare educator, blogger, and the content creator behind Skin Science by Mira and The Skincare Forum on Facebook. While skincare keeps her busy, she’s also pursuing her degree in Nursing and loves to spend her free time hiking.  As a content writer for Stratia Skin, Mira shares her evidence-based approach to skincare topics and a passion for making science accessible.