It appears that products claiming protection against high energy visible light are still around and on the rise. A Mintel¹ search of the term “blue light” for prestige beauty and personal care products in North America for the past five years yielded 1,254 results. According to Mintel’s tool, it appears that the overall trend in the US for skincare products touting blue light protection is driven by an increased consumer awareness, demand for multifunctional products and a focus on comprehensive skin wellness.  

In the US, 22% of consumers (aged 18+ who use sunscreen or cosmetics with SPF) look for products that protect against blue light. The key demographics are younger, tech-savvy, health-conscious individuals, often residing in urban areas, who prioritize skin wellness and protection against digital and environmental stressors. There is a growing awareness about the potential harmful effects of blue light exposure from digital devices. However, consumer perceptions of the effectiveness of products with blue light protection vary and there is some skepticism about their efficacy. In the US, only about 19% of consumers believe that products with blue light protection work as advertised.

What Does Science Say?

We can take measures to avoid and protect ourselves from sunlight radiation but what about visible light? What does science say? It has been about five years since I wondered if visible light in the blue region (wavelength: 450-500 nm²) had any biological deleterious effects on humans and if we needed protection against it. I investigated the literature and wrote about it in the January 2021 issue of Happi.³ As with my previous article, I again jumped on to PubMed⁴ online, where peer reviewed scientific/authoritative references are listed, and searched for “blue light.” I got 40,129 results (as of March 12, 2025). That’s about 8,400 more papers since my last article—about five years. For the span 2020 to March 12, 2025, there were 13,659 results. That is a lot of interest in blue light. But not all of it is skin related. To get an idea, here is an example of some of the paper titles, excluding those that dealt with skin as I will discuss separately:

• Mechanisms of blue light-induced eye hazard and protective measures: a review—2020.
• In search of blue-light effects on cognitive control—2021
• The potential “blue light hazard” from LED headlamps—2022
• Blue Light-Induced Retinal Neuronal Injury and Amelioration by Commercially Available Blue Light-Blocking Lenses—2022
• Blue light pollution causes retinal damage and degeneration by inducing ferroptosis—2022
• Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review—2023
• Long-term blue light exposure impairs mitochondrial dynamics in the retina in light-induced retinal degeneration in vivo and in vitro—2023
• Blue Light-Ocular and Systemic Damaging Effects: A Narrative Review—2023
• Blue light-induced ferroptosis via STAT3/GPX4/SLC7A11/FTH1 in conjunctiva epithelium in vivo and in vitro—2024
• Blue light-induced phototoxicity in retinal cells: implications in age-related macular degeneration—2024
• Exposure of A2E to blue light promotes ferroptosis in the retinal pigment epithelium—2025

I did not select these for any particular interest or reason but did want to include at least one example, and no more than three, from each year. As it appears from these titles, most papers deal with vision. That makes sense as we spend many hours a day outdoors, staring at our electronic devices, or both. The eye is designed to detect/absorb photons in the visible range. And since the smaller the wavelength the higher the light energy,⁵ the greater the probability that it will interact with matter to transfer that energy and affect that matter. For more on how blue light negatively affects biological matter, please see my previous article.³

Blue Light and the Aging Process

I’m sure most Happi readers are, as I am, interested in how blue light affects skin. After all, cosmetic industry interest is on photobiological effects of the skin. A recent review article⁶ assessing the literature concluded that blue light accelerates the skin aging process and yields hyperpigmentation by acting on nitric oxide and producing reactive oxygen species (ROS). However, the literature did not reveal much about the precise process of how this happens. Read on for a clue. 

Since I was curious as to what new research was conducted and if this is a topic still of interest, I searched for “blue light” and “skin,” and got 512 results for the same span of time. Not much interest compared to that of the eye. Since blue light comes from multiple sources, including the sun, its deleterious effect on the skin depends on exposure. Not considering the sun, is skin exposure from the other multiple sources such as electronic devices whose irradiance is 100 to 1,000-fold less than that of the sun⁷ sufficient to result in a photobiological effect like pigmentary changes? Duteil et al., did not think so.⁷ Not all publications I came across were on deleterious effects but here are some examples:

• Pigmentation effects of blue light irradiation on skin and how to protect against them—2020
• Violet-blue light exposure of the skin: is there need for protection?—2021
• Effects of visible light on mechanisms of skin photoaging—2022
• Blue light induces skin apoptosis and degeneration through activation of the endoplasmic reticulum stress-autophagy apoptosis axis: Protective role of hydrogen sulfide—2022
• Blue light induces DNA damage in normal human skin keratinocytes—2022
• The impact of blue light and digital screens on the skin—2023
• Induced skin aging by blue-light irradiation in human skin fibroblasts via TGF-beta, JNK and EGFR pathways—2023
• Damaging effects of UVA, blue light, and infrared radiation: in vitro assessment on a reconstructed full-thickness human skin—2023
• Screens, Blue Light, and Epigenetics: Unveiling the Hidden Impact on Skin Aging—2024
• An important step towards the comprehensive sun protection: Blue-light exposure inhibits DNA repair in reconstituted human skin and a broadband sunscreen avoids this inhibition—2024
• Blue light inhibits cell viability and proliferation in hair follicle stem cells and dermal papilla cells—2024
• Blue Light-Induced Pigmentation—2025
• The Pigmentation of Blue Light Is Mediated by Both Melanogenesis Activation and Autophagy Inhibition through OPN3-TRPV1—2025
• Balancing act: optimizing blue light for melanogenesis while minimizing cellular damage in primary human skin cells—2025
• Protective effect of melatonin against blue light-induced cell damage via the TRPV1-YAP pathway in cultured human epidermal keratinocytes—2025

There are also many articles on the therapeutic uses of blue light. If the reader is interested in that, a good place to start is with Paolo Giacomoni’s articles in Happi.^8,9 In addition to the above listed titles from PubMed I would also like to give you some highlights of papers and articles I have read since 2021 from my personal library. In no order of importance but of interest to me and I hope informative to you.

More Resources Devoted to Blue Light

In a recent article entitled, “The Pigmentation of Blue Light Is Mediated by Both Melanogenesis Activation and Autophagy Inhibition through OPN3-TRPV1,” the authors “investigated the involvement of TRPV1-mediated signaling along with OPN3 in blue light-induced melanogenesis as well as its signaling pathway.”¹⁰ TRPV1, also known as capsaicin receptor that plays a role in pain sensing, is a nonselective cation channel expressed in human skin.^11,12 OPN3 is a sensor in melanocytes responsible for hyperpigmentation that can sense UV and blue lights, causing a calcium influx.¹³ Simply put, TRV1 appears to be the central mediator of blue light induced melanogenesis. The investigators surmised that this is a “previously unreported signaling pathway through which blue light regulates melanocyte biology.”¹⁰

As a response to this research, I. Kohli and HW Lim¹⁴ pointed out two limitations that are significant if one were to extend these findings to sun exposure. These results were based on cell in vitro and that does not necessarily reflect in vivo. In vivo structural integrity and repair mechanisms are not maintained in vitro. Also, the cells they used (HEMn = Human Epidermal Melanocyte neonatal), are very sensitive to blue light irradiation and their response may not reflect that of in vivo. So further validation is required with human studies following realistic outdoor sun exposure.

Is There a Need for Standardization?

In my previous article,³ I questioned if the cosmetic industry will ever develop a standardized method of blue light protection based on the SPF and maybe calling it “BPF.” Perhaps the time has not yet arrived for some kind of industry standardization, but products that claim blue light protection should be able to demonstrate protection and the level of protection they offer. Although some methods have been published, none are yet standardized.

In a 2021 review article, Lim et al. addressed standardization.¹⁵ Since there is plenty of literature that shows blue light has some biological effects on the skin, some manufacturers may use that knowledge to conduct in vitro testing on ingredients and finished products. In vitro studies tend to focus on oxidative endpoints, inducing matrix metalloproteinase expression, invoking DNA damage and attenuation of collagen production.¹⁵ However, in vitro does not necessarily reflect what happens in vivo and may not be relevant to skin health and aging.¹⁵ Based on the literature knowledge of blue light’s deleterious effects, other methods, especially intended for finished products, use spectrophotometry. That is, obtaining data on light transmittance/absorbance and making calculations to determine the efficacy endpoints and thus making protection claims.¹⁵ But, the reader should heed the Federal Trade Commission’s advice and not make exaggerated connections. For more information on FTC claims guidance see L. Kromidas et al. (2023) Happi article.²⁰ 

Bottom line, in vitro studies should only be used as screening tools or supporting evidence to human in vivo studies. Ex vivo methods, that is, skin explants, provide stronger claim substantiation over skin cells in a petri dish because they maintain a normal-thickness stratum corneum with more of intact skin (in vivo) characteristics like architecture and relationships between different cell types.¹⁵ Unlike isolated cells in vitro, explants also consider skin penetration and bioavailability.¹⁵ But still, one can get challenged that they are not completely reflective of in vivo. In vivo methods, therefore, are clearly the most representative of real life and give the strongest claim substantiation. In vivo methods also have limitations such as the logistics of using human subjects, the variability among human subjects, as well as that of the mechanics of devices emitting at the blue light range. 

As I mentioned, Lim et al.¹⁵ from the Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI, discussed standardizing methodology to address hyperpigmentation. Based on that and my opinions, I make the following suggestions:

• Cell-based in vitro studies are only to be used for screening raw material/ingredients for potential protective effects but not to assess protective effects in the finished cosmetic product.
• Ex vivo studies should be used to confirm preliminary results obtained in vitro and to gauge the potential results of a human study.
• Subsequent spectrophotometry studies on finished cosmetic formula may be used to confirm initial findings.
• Findings from any or all the above studies may be used to support findings using human subjects (i.e., in vivo).
• All studies should be performed with appropriate controls.
• In line with the current SPF testing methodology, a minimum of 10 subjects should be used to evaluate hyperpigmentation.
• To ensure detectable pigmentary changes in a melano-competent population, the subjects’ skin type should be Fitzpatrick phototypes III-V;¹⁶ of course, depending on one’s objectives, other phenotypes may be included. For example, if the emphasis is on erythema or protecting those of phenotype I and II.
• Exposure to light should be as close as possible (in terms of percentage contribution and irradiance) to that emitted by the sun unless one’s aim is protection from electronic devices. In terms of the latter, one may adjust appropriately. It is worth mentioning, however, that in a poster presented at the 27th EADV Congress in Paris, Beiersdorf AG reported that the amount of blue light emitted during conventional use of devices is not enough to trigger harmful skin effects.¹⁷ It was determined “that one week, uninterrupted, sitting just 30cm in front of a monitor is equal to one minute outside on a sunny summer day in Hamburg” Germany.¹⁷ A letter to the Editor of the Journal of the American Academy of Dermatologist pretty much said the same.¹⁸ Shiseido researchers, on the other hand, reported that they observed changes in skin conditions such as oxidative damage factor (porphyrin), irregular corneocytes and deterioration of the skin barrier function with several consecutive day of prolonged exposure to electronic devices.¹⁹  
• As is common for UVA and UVB testing, a single dose of radiation should be used unless the aim is to show protection from cumulative dosing.
• As for SPF testing, a reference product application amount should be established. Irradiation should be performed 30 minutes after the application of product at a concentration of 2.0 mg/cm² . 
• Site of application and spectral output, a dose (J/cm²) should be clearly noted and justified. 480 J/cm² corresponds to approximately 2.5 hours of outdoor sun exposure.¹⁵ 

Postscript

Blue light comes from multiple sources and can affect matter due to its higher intensity making it hard to ignore. Because of its longer wavelength than UV, it penetrates deeper into the skin and may result in deleterious or therapeutic effect, depending on dose and exposure. Scanning the literature, it looks like the primary focus is the deleterious effects on the eyes and, secondarily, on the skin. However, blue light can be used to treat anything from mood and sleep dysfunctions to antimicrobial activity and acne.

It behooves the cosmetic industry though to “stay in its lane” and not make structure function or drug claims. Claim substantiation should be founded on in vivo principles. When, and if the marketing day comes to consider standardizing methodology to make cosmetic claims, I hope the above-mentioned suggestions are considered as foundation.

About the Author

Lambros Kromidas, MS, PhD, is VP, Global Legal—Regulatory Affairs Liaison at Shiseido. Prior, he held management positions at Avon, Coty, Beiersdorf and RIFM. 

He received his MS in microbiology and PhD in toxicology from St. John’s University, New York, NY, and conducted post-doctorate research at Cornell University Medical College, Department of Physiology, New York, NY. 

He is a member of SCC, SOT, and an active participant of the PCPC and an occasional Happi contributor.

References

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4. National Library of Medicine (NIH). National Center for Biotechnology Information. PubMed (https://pubmed.ncbi.nlm.nih.gov/). An official website of the United States government.
5. National Aeronautics and Space Administration (NASA). The Electromagnetic Spectrum (https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum2.html, retrieved December 2020).
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7. L Duteil, et al. 2020. Short-term exposure to blue light emitted by electronic devices does not worsen melasma. J Am Acad Dermatol, 83: 913-914.
8. P Giacomoni. February 2025. Light Has a Role To Play In Skincare Treatments. HAPPI (https://ajay.happi.rodmanadmin.com/light-has-a-role-to-play-in-skincare-treatments/).
9. P Giacomoni. March 2025. Treating Skin with Light (Part II). HAPPI (https://ajay.happi.rodmanadmin.com/treating-skin-with-light-part-ii/).
10. E Yu, et al. 2025. The Pigmentation of Blue Light Is Mediated by Both Melanogenesis Activation and Autophagy Inhibition through OPN3-TRPV1. J Inv Dermatol, 145: 908-918.
11. MJ Caterina and Z. Pang. 2016. TRP channels in skin biology and pathophysiology. Pharmaceuticals (Basel), 9: 77.
12. DH Kwon, et al. 2021. Heat-dependent opening of TRPV1 in the presence of capsaicin. Nat Struct Mol Biol, 28: 554-563. 
13. C Regazzetti, et al. 2018. Melanocytes Sense Blue Light and Regulate Pigmentation through Opsin-3. J Invest Dermatol, 138(1): 171-178.
14. I Kohli and HW Lim. 2025. Blue Light-Induced Pigmentation. J Inv Dermatol, 145: 723-724.
15. HW Lim, et al. 2021. Photoprotection of the Skin from Visible Light‒Induced Pigmentation: Current Testing Methods and Proposed Harmonization. J Invest Dermatol, 141(11): 2569-2576.
16. A Oakley. Fitzpatrick skin phototype. DermNet (https://dermnetnz.org/topics/skin-phototype; retrieved 4/18/2025).
17. R Grabenhofer. May 5, 2021. Beiersdorf Refutes Reports that Artificial Blue Light Causes Skin Damage. Cosmetics & Toiletries (https://www.cosmeticsandtoiletries.com/research/biology/Beiersdorf-Refutes-Reports-that-Artificial-Blue-Light-Causes-Skin-Damage_574355941.html).
18. L Duteil, et al., 2020. Short-term exposure to blue light emitted by electronic devices does not worsen melasma. Research Letters to the J Am Acad Dermatol, 83(3): 913-914.
19. R Grabenhofer. May 4, 2021. Shiseido Decodes Negative Impact of Digital Fatigue in Skin. Cosmetics & Toiletries (https://www.cosmeticsandtoiletries.com/research/biology/Shiseido-Decodes-Negative-Impact-of-Digital-Fatigue-in-Skin_574346551.html)
20. L Kromidas, Stuart Lee Friedel and Alexa Meera Singh. April 2023. FTC Claims Guidance. FTC Health-Related Claims Guidance & Its Impact on General Advertising. Happi, 60(4): 38-43 (https://happi.texterity.com/happi/april_2023/MobilePagedReplica.action?utm_source=newsletter&utm_medium=email&utm_campaign=TXHAPP230403002&utm_content=gtxcel&pm=2&folio=38#pg38).