Less than 10% of the light reaching earth is UV radiation1. Although 10% is a relatively low percent the impact of UV light on unprotected skin can be catastrophic. Continual exposure can eventually lead to incurable skin cancers. As a consequence of these devastating effects UV light has taken centre stage and investigations into the impact of visible light on skin has taken a back seat – until now.
Visible light can impact a person’s skin both positively and negatively. For instance certain wavelengths of visible light can promote skin healing whereas other wavelengths of visible light can supress skin healing. Certain skin types may over express pigmentation when exposed to visible light whereas other skin types show no reaction. Certain colours of visible light have potential to cause cell death whereas other colours of visible light do not induce notable cell destruction.
New research suggests visible light can have a statistically significant impact on skin ageing. Precautionary recommendations and skincare practices used to protect skin against UV light will not protect a person’s skin against visible light. It is therefore important to understand the impact of visible light on skin in addition to how visible light damage can be protected against.
What is visible light?
Visible light is a defined range of radiation wavelengths which can be seen by the human eye. It is most common for visible light to be defined as any kind of light having a wavelength of between 400 to 700 nm2. Visible light is most easily thought of as a rainbow of colours ranging from violet to red. Each distinct colour of the visible light rainbow has a knowable and corresponding wavelength i.e. red light has a wavelength of around 660nm – a type of light which is now being often used to treat acne and skin ageing3
As visible light is becoming a common treatment protocol for skin conditions ranging from acne to eczema it’s of extreme importance scientists understand potential visible light side effects.
While visible light is the only light which can be seen by the human eye – visible light is a part of the overall radiation spectrum. Within this spectrum visible light sits between UV radiation and Infrared radiation. It is therefore easy to see why visible light may have harmful effects on skin as the only key distinction between UV and visible light is whether the human eye can see it.
Note: The correct term for describing a type of ‘light’ which cannot be seen by the human eye is radiation. The phrase light is most correctly used to refer to a type of radiation which can be seen by the human eye e.g. all kinds of visible light. Visible light is therefore also a type of radiation.
Does visible light damage skin?
The most common way in which light damages skin is by the production of free radicals i.e. atoms or molecules with an intense energy. Production of free radicals can be measured in a controlled laboratory setting making it fairly easy to understand whether visible light can damage skin i.e. to note whether on exposure to visible light skin generates free radicals.
A study published in 2006 measured the impact of visible light on skin by measuring the destruction of vitamin C. Vitamin C is a well-known antioxidant which is naturally present inside of human skin. When vitamin C is exposed to radiation it can be turned into a vitamin C radical (ascorbate radical)4. Scientists noted when skin was exposed to UV radiation vitamin C radical production was 67% greater and when skin was exposed to visible light vitamin C radical production was 33% greater. It can therefore be concluded visible light can damage skin, however to a lesser extent than UV light.
The same study also concluded sunscreens are an ineffective method of protection against visible light – keep reading to find out how best to protect skin against visible light.
What are the harmful effects of visible light?
Visible light can have many harmful, non-harmful and beneficial effects on skin. Sometimes the negative or positive impact of visible light on skin is due to dose. Other times the negative or positive impact of visible light on skin is due to the wavelength i.e. blue visible light or red visible light.
To date studies have shown;
- Blue visible light with a wavelength of 415nm can cause an increase in pigmentation – note this test was completed in real-life human volunteers5. The test also showed blue-violet light caused a significantly more pronounced hyperpigmentation than UVB light – lasting averagely for 3 months. This is an important learning for anyone living with or experiencing a pigmentation skin disorder such as melasma. Sunscreen should not be the only kind of skincare used to help protect against pigmentation, hyperpigmentation and melasma.
- Blue light (430 to 510nm) has been studied in animal model to slow down skin recovery whereas red light (550 to 670nm) has been shown to speed up skin recovery6 – red visible light is commonly used for anti-ageing i.e. to increase collagen production and therefore this learning is of significance. The same study also noted white light had no effect. White light is a combination of all wavelengths of light – therefore it contains both blue and red light. It may therefore be understood certain wavelengths of light could counteract each other.
- It is extremely unlikely that exposure to visible light could cause skin cancer. UV light is known to cause DNA damage/mutation which is a key cause of skin cancer. In 2002 researchers studied whether visible light could induce similar DNA mutations – it could not7.
- Pigmentation caused by exposure to visible light is studied to last longer than pigmentation cause by UVA light. The pigmentation caused by exposure to visible light is also a different colour. UVA induced pigmentation is usually grey-brown, visible light induced pigmentation is usually brown-red8.
- Visible light induced pigmentation required significantly more energy to produce. A paper published in 2010 reported 5 J/cm2 of UVA light caused the same pigmentation strength as 40 J/cm2 of visible light i.e. 8 times more visible light is needed to induce the same darkening of skin as UV light. In summer it would take around 30 minutes to expose skin to 40 J/cm2.
- Exposure to visible light can change the lipid composition of a person’s skin. Most notably exposure to visible light can lead to an increased production of ceramides but a decreased production of squalene9. Both are vital components of skin’s barrier function. The impact of these changes is not yet known.
Bottom line: Visible light is not considered mutagenic or a carcinogen however visible light is studied to deplete skin’s own antioxidant resources in addition to causing pigmentation. Visible light protection may therefore be important for people concerned with signs of skin ageing in addition to those concerned with pigmentation i.e. post inflammatory pigmentation caused by acne/spots and melasma. As skin can become prone to melasma during pregnancy it may be of extra importance to protect skin against visible light during and immediately after pregnancy.
Does sunscreen protect against visible light?
Sunscreens were first created to protect against UVB exposure and then updated and reformulated to help protect skin against ageing UVA exposure. This is why sunscreen rating systems have evolved considerably over the last decades i.e. SPF is a measure of UVB protection and PA+ or the UVA circle or the claim broad spectrum are a measure of UVA protection.
Commercial sunscreens are therefore designed to block wavelengths of light up to 380nm. Visible light begins at a wavelength of 400nm and therefore most commercial sunscreens provide negligible protection against visible light. A study published in 2012 in the Journal of Investigative Dermatology concluded sunscreen alone had minimal effects on reducing skin damage caused by visible light – however the same study also concluded specific antioxidants added to a sunscreen can help protect against the harmful effects of visible light10 – we’ll be detailing which antioxidants soon.
Scientists understand only opaque sunscreen filters are able to protect skin against visible light damage i.e. sunscreen filters which can also be seen by the human eye. Therefore natural mineral filters such as zinc oxide and titanium dioxide have potential to protect skin against visible light. A common complaint when using mineral sunscreen is that the fluids are white and not easily rubbed in – many consumers describe mineral sunscreens as leaving them looking white as a ghost. To improve the perception and usability of mineral sunscreens companies now use micronized or even microfine mineral filters. These mineral filters have a much smaller particle size and are therefore not as visible to the human eye – they are also therefore not as effective visible light protectors.
Note: Unlike UVB light which is mostly filtered away by window glass both UVA and visible light are easily transmitted through window glass. Human skin is therefore exposed to visible light daily and any form of skin protection must be used 365 days per year.
How to protect yourself from visible light
Most sunscreens provide minimal protection against the harmful effects of visible light – however there are active skincare ingredients which are studied to prevent visible light from penetrating and reacting with skin. There are primarily 2 ways skin can be protected against visible light;
- By pigments commonly used in foundations, concealers and BB creams
- By use of antioxidants (both through diet and skincare11)
Ingredients which are studied and proven to help protect skin against visible light damage include;
- Iron oxide
- Green tea extract – also known as epigallocatechin-3-gallate
- A combination of feverfew extract – tanacetum parthenium, soy extract – glycine soja and vitamin E as gamma tocopherol
The same sunscreen used with and without this 3rd combination of antioxidants showed both 0% protection against visible light and up to 87% protection against the harmful effects of visible light12. Respectively the formulation without antioxidants showed over an 85% skin increase in free radicals on exposure to visible light whereas the sunscreen used with antioxidants showed a 54% skin reduction in free radicals created by visible light.
Regular use of antioxidant rich skincare like our griffin+row Enrich antioxidant night cream can help protect skin against the harmful effects of visible light.
Use of foundations, BB cream or even sunscreens with a tint (iron oxide containing sunscreens) can help to provide daily protection against light damage to skin. Iron oxide for example is commonly used in tinted products. Different types of iron oxide range in colour from yellow to orange to red to brown. Iron oxide is very effective in helping protect skin against visible light because it itself can be seen.
Remember – visible light filters only work when they can also be seen by the human eye.
Therefore any kind of skincare products which can be seen on top of skin are likely helping provide additional protection against visible light induced pigmentation and skin stress.
People with a skin type prone to pigmentation should also carefully consider visible light treatments for example red light therapy (most common against ageing) or blue light therapy (most common against acne). Pigmentation can present as uneven skin tone, acne scars, dark marks, age spots or even melasma. Symptoms such as these are warning signs a person’s skin type is prone to pigmentation damage. Therefore such therapies may not be appropriate – in cases like these other forms of anti-ageing or anti-acne skincare should be considered.
Bottom line: Visible light can cause damage to skin however visible light damage may be easily protected against by using skincare rich in antioxidants in addition to tinted or iron oxide rich foundations.
References and sources
- Irradiation of Skin with Visible Light Induces Reactive Oxygen Species and Matrix-Degrading Enzymes Liebel, Frank et al. Journal of Investigative Dermatology , Volume 132 , Issue 7 , 1901 – 1907
- Effects of visible light on the skin. Bassel H. Mahmoud, Camile L. Hexsel, Iltefat H. Hamzavi, Henry W. Lim
Photochem Photobiol. 2008 Marâ€“Apr; 84(2): 450–462. Published online 2008 Jan 29. doi: 10.1111/j.1751-1097.2007.00286.x
- Papageorgiou, P. , Katsambas, A. and Chu, A. (2000), Phototherapy with blue (415 nm) and red (660 nm) light in the treatment of acne vulgaris. British Journal of Dermatology, 142: 973-978. doi:10.1046/j.1365-2133.2000.03481.x
- Relevance of sunscreen application method, visible light and sunlight intensity to free-radical protection: A study of ex vivo human skin. Rachel Haywood, Photochem Photobiol. 2006 Julâ€“Aug; 82(4): 1123–1131.
- Duteil, L. , Cardot‐Leccia, N. , Queille‐Roussel, C. , Maubert, Y. , Harmelin, Y. , Boukari, F. , Ambrosetti, D. , Lacour, J. and Passeron, T. (2014), Differences in visible light‐induced pigmentation according to wavelengths: a clinical and histological study in comparison with UVB exposure. Pigment Cell Melanoma Res., 27: 822-826. doi:10.1111/pcmr.12273
- Visible Radiation Affects Epidermal Permeability Barrier Recovery: Selective Effects of Red and Blue Light
Denda, Mitsuhiro et al. Journal of Investigative Dermatology , Volume 128 , Issue 5 , 1335 – 1336
- Irradiation of Skin with Visible Light Induces Reactive Oxygen Species and Matrix-Degrading Enzymes
Liebel, Frank et al. Journal of Investigative Dermatology , Volume 132 , Issue 7 , 1901 – 1907
- Impact of Long-Wavelength UVA and Visible Light on Melanocompetent Skin Mahmoud, Bassel H. et al.
Journal of Investigative Dermatology , Volume 130 , Issue 8 , 2092 – 2097
- Lohan, S. B., Müller, R. , Albrecht, S. , Mink, K. , Tscherch, K. , Ismaeel, F. , Lademann, J. , Rohn, S. and Meinke, M. C. (2016), Free radicals induced by sunlight in different spectral regions – in vivo versus ex vivo study. Exp Dermatol, 25: 380-385. doi:10.1111/exd.12987
- Irradiation of skin with visible light induces reactive oxygen species and matrix-degrading enzymes.
Frank Liebel, Simarna Kaur, Eduardo Ruvolo, Nikiforos Kollias, Michael D. Southall, J Invest Dermatol. 2012 Jul; 132(7): 1901–1907. Published online 2012 Feb 9. doi: 10.1038/jid.2011.476
- Morley, N., T. Clifford, L. Salter, S. Campbell, D. Gould and A. Curnow (2005) The green tea polyphenol (-)-epigallocatechin gallate and green tea can protect human cellular DNA from ultraviolet and visible radiation-induced damage. Photodermatol. Photoimmunol. Photomed. 21, 15–22.
- Irradiation of skin with visible light induces reactive oxygen species and matrix-degrading enzymes. Frank Liebel, Simarna Kaur, Eduardo Ruvolo, Nikiforos Kollias, Michael D. Southall, J Invest Dermatol. 2012 Jul; 132(7): 1901–1907. Published online 2012 Feb 9. doi: 10.1038/jid.2011.476