The question of blue light is usually asked about phone and computer screens, whereas the scientific sources we rely on examine visible light from the sun. This difference shapes both the answer to the question “is it harmful?” and how the wording “blue light protection” on a label should be read.
In short: Blue light is the short-wavelength, high-energy end of visible light (400–700 nm); it is also known as HEV. In darker skin tones (phototypes IV–VI), visible light from the sun can cause more intense and longer-lasting pigmentation than UVA1. According to a 2022 review, no country has guidelines for testing protection against visible light; SPF shows UVB protection only. Our sources contain no data on the effect of screen light on the skin.
What is blue light (HEV)?
Blue light is the short-wavelength end of visible light in the 400–700 nanometre (nm) range, closest to violet and blue; this is where the name HEV (high-energy visible light) comes from. Besides the sun, lasers, LEDs (light-emitting diodes) and flash lamps are also sources of visible light.
In sunlight, UV rays lie just below visible light. The ranges mentioned in the sources:
| Light | Wavelength | Effect highlighted in the sources |
|---|---|---|
| UVB and short-wave UVA2 | 290–340 nm | Considered the part of sunlight that causes redness (erythema) |
| UVA1 | 340–400 nm | Its long-wave part (370–400 nm) can intensify the pigmentation effect of visible light |
| Visible light (including blue light) | 400–700 nm | Can cause pigmentation and redness |
Is blue light harmful to the skin?
Visible light from the sun, including blue light, can cause pigmentation and redness in the skin; how pronounced the effect is varies with skin tone. Visible light can reach the full thickness of the skin; it is absorbed by light-sensitive molecules (chromophores) such as melanin, haem and opsins, and changes how the skin functions.
- In darker skin tones: in people with phototypes IV–VI, visible light can cause more intense and longer-lasting pigmentation than UVA1. According to the AAD, the darker the skin tone, the greater the risk that UV rays and visible light from the sun will cause dark spots.
- In lighter skin tones: visible light together with long-wave UVA1 has been found to cause redness in people with phototypes I–III. Because redness was long attributed only to UVB and UVA2, this is a new finding.
- In the look of ageing: a 2021 review draws attention to evidence that visible light and infrared light may play a role in sun-related ageing (photoageing).
The limit of these findings is clear: the sources examine visible light as a whole, and blue light is one part of this range. Austin and colleagues state that more research is needed to determine the functional importance of visible light for skin health, separately from the effects of UV and infrared rays. For causes of the look of dark spots other than light, see why dark spots form on the skin.
Do phone and computer screens affect the skin?
The sources we rely on do not offer a conclusion on what screen light does to the skin, so we do not draw conclusions about screens. Although LEDs count as a source of visible light, the pigmentation and redness findings we reviewed concern sunlight and visible light itself. Definitive statements such as “screen light ages the skin or causes dark spots” are not supported by these sources; in practice, the focus of protection is the time spent in the sun.
Does SPF or the wording “blue light protection” show protection against visible light?
No: SPF shows protection against UVB only, and there is no common test method for visible light protection. When you see the wording “blue light” or “visible light” on a label, bear the following in mind:
- SPF does not measure visible light. According to the AAD, SPF shows how well a sunscreen filters the UVB rays that cause sunburn.
- “Broad spectrum” refers to UVA and UVB. According to the AAD, this term means that the product protects against both types of UV; visible light is not part of the definition.
- There are no test guidelines. According to a 2022 review, no country has guidelines for testing protection against visible light and the long-wave UVA1 range; the wording does not carry a value measured by a standard test, as SPF does.
- Filter options are limited. According to a 2021 review, at that time none of the sunscreen filters authorised in the US protected against visible light, and few protected against long-wave UVA (above 370 nm).
- Terms without an official meaning. According to the AAD, “SPF” and “broad spectrum” have specific meanings that come from FDA testing standards, while some terms often seen on labels have no such official meaning.
In the s'hevec range, Just Protected From Sun was formulated with blue light protection as an aim; no measured protection value is claimed.
How to read an SPF value and the difference between UVA and UVB are explained in our guide to SPF and UVA/UVB.
How can you protect your skin from visible light?
To protect against visible light, the AAD recommends not a single product but an approach based on three measures applied together:
- Seek shade. Reduce the time you spend in the sun by staying in the shade.
- Wear protective clothing. Wear lightweight, long-sleeved clothing, a wide-brimmed hat and sunglasses with UV protection.
- Choose your sunscreen accordingly. The AAD recommends a broad-spectrum sunscreen with SPF 30 or higher that says “tinted” on the label; when outdoors, reapply it every two hours and after towel-drying, sweating or swimming.
The filter type is also part of the choice: for sensitive skin, the AAD recommends physical (mineral) sunscreens. We compared chemical, physical and hybrid filters in our article what is a hybrid sunscreen. These are general recommendations from the AAD; you can find s'hevec sunscreens and their label claims together in our SPF 50+ sunscreens collection.
What should people with darker skin and a tendency to dark spots look out for?
According to the AAD, protection from visible light is particularly useful for people with darker skin tones; in this group, the three measures above do not replace one another.
- Sunscreen alone is not enough. According to the AAD, no sunscreen can filter out all UVB rays; this is why shade and protective clothing are separate steps.
- When switching to a new sunscreen: Before first use, do a patch test on the inner forearm.
- If you notice unexpected redness after brief sun exposure, or if dark spots get a little darker every summer: see your doctor to find out whether light is the trigger.
The look of dark spots that have already formed, however, is a matter for evening care, separate from protection against light. In the s'hevec range, this step is covered by Hit The Spot Dark Spot Serum (2% tranexamic acid and 2% alpha arbutin, mainly for evening use) and Shine On You Azelaic Acid Cream (7% azelaic acid and 3% niacinamide, evening). Neither provides protection against light, and neither replaces daytime sun protection.
Frequently asked questions
Are HEV and UV the same thing?
No. UV rays lie below 400 nm and cannot be seen; HEV is part of visible light and is present in sunlight together with UV.
Does blue light age the skin?
For visible light from the sun, the sources go as far as “there is evidence that it may play a role in ageing”; this is not a definitive conclusion. Our sources contain no such finding for screen light.
Is blue light always harmful?
There is no single verdict. According to the review by Austin and colleagues, lasers and light devices are used in clinics for some skin problems, with specific wavelengths and settings chosen for the purpose. If you are thinking of using a light device, consult your doctor first.
Why is tinted sunscreen recommended?
According to the AAD, tinted sunscreens contain iron oxide, and research shows that iron oxide helps protect the skin against visible light. The AAD notes that these products can also help prevent the white cast that some sunscreens leave. This is general information about tinted sunscreens; the claims for Crush On Pink are on its product page.
Sources
- Austin E et al. Visible light. Part I: Properties and cutaneous effects of visible light. J Am Acad Dermatol. 2021.
- Ezekwe N et al. Visible Light and the Skin. Photochem Photobiol. 2022.
- Guan LL et al. Sunscreens and Photoaging: A Review of Current Literature. Am J Clin Dermatol. 2021.
- American Academy of Dermatology (AAD). Understand sunscreen labels.
This content is for information only and does not replace medical advice. s'hevec products are cosmetic products and are not intended for medical treatment. It was prepared by the s'hevec Team on the basis of the s'hevec product data library and the sources listed above.
