UV radiation and its effect on the skin

Types of light

There are forms of light visible to the human eye and invisible forms. To explain this, we need to take a brief detour into physics. But don't worry, it will be an easy-to-understand one.

Light is a wave. There are other types of waves, such as radio waves, microwaves, X-rays, and radioactive waves, which differ from one another in their wavelengths. We can perceive the color spectrum of light waves, from red to violet (essentially the classic rainbow). Infrared has a wavelength that lies above the red visible to us. Similarly, ultraviolet light has a wavelength below the violet visible to the human eye. Ultraviolet light can be further divided into UVA, UVB, and UVC rays. These will be discussed in more detail in the following sections.

Why is UV light harmful?

UV rays are very high-energy. When they reach Earth, they interact with the matter they encounter. When they interact with human skin, this can damage the cell's DNA. Depending on whether the UV light is long-wave or short-wave, it penetrates the skin to varying depths and can therefore cause different types of damage. Sunscreen essentially forms a layer on the skin, providing an alternative way for the light to interact with it. With chemical UV filters, for example, this interaction results in the energy being converted into harmless heat, thus preventing potential damage to the skin. You can read more about the differences between various UV filters in our article " Ingredients in Sunscreens: Which ones are problematic? "

UVA radiation

UVA rays are long-wavelength rays that can penetrate relatively deep into the skin and directly damage cellular DNA. Therefore, they can cause a wide range of damage beyond the classic sunburn. UVA radiation can lead to premature skin aging, an effect also known as photoaging. The radiation destroys the skin's own substances responsible for elasticity. Photoaging can result in wrinkles, sagging skin, and a dull complexion. The most serious damage caused by UVA radiation is melanoma (skin cancer).

Of the different types of UV radiation, UVA is the most dangerous. Furthermore, UVA rays reach the Earth year-round, are not lost in the atmosphere, and, unlike UVB rays, penetrate window glass. They make up the majority of the UV light that reaches the skin.

UVB radiation

UVB radiation is not as dangerous as UVA. However, it can still cause sunburn and redness, as well as pigment spots, and in the worst case, even skin cancer. But it also has positive effects on the skin. UVB radiation stimulates the production of vitamin D and melanin, thus contributing to our well-being and the summer tan that many people desire.

UVB rays differ significantly from UVA rays. Only about ten percent of UVB rays reach the Earth's surface, and even then, the amount varies throughout the year. In sunny regions and during periods of high sunlight, such as summer, more UVB radiation reaches the Earth than during cloudy periods.

UVC radiation, infrared and blue light

Now let's turn to the types of radiation that are less frequently discussed. UVC radiation is also a form of UV light, but it is completely harmless to humans because it is entirely lost in the atmosphere.

Infrared light is often used for warmth and can therefore be beneficial. However, this light can also lead to premature skin aging. Vitamins C and E protect against the negative effects of infrared radiation. So, if your skincare products contain these vitamins, you don't need to worry about infrared light at all.

Blue light can penetrate even deeper than UV light. Otherwise, it has similarly harmful effects. Like UV light, blue light reaches us during the day, reaching its highest intensity around midday. Aside from naturally occurring blue light, we are also frequently exposed to it through the screens of PCs, smartphones, and tablets. Our Daily SPF 50+ Moisturizer also protects against blue light thanks to the active ingredient carnosine. Incidentally, of the light spectra mentioned here, blue light is the only one that can be perceived by the human eye.

The sun protection factor

The term sun protection factor (abbreviated SPF) is essential to the topics of UV light and sun protection. The SPF level is crucial when buying sunscreen. However, it's often not so easy to understand exactly what the factor means and whether an SPF of 30 is better than an SPF of 50.

First and foremost, it's important to understand the definition of SPF: skin has its own natural protection. Depending on skin tone and tan, the duration of this natural protection varies. For fair skin, the time one can safely spend in the sun unprotected is often only ten minutes. For darker skin tones, this can be up to 90 minutes. The SPF indicates by what factor this natural protection time is extended. Theoretically, with an SPF of 30, you could stay in the sun thirty times longer than unprotected, and with an SPF of 50, fifty times longer. However, this is only a theoretical calculation. In reality, the protection diminishes over time, simply due to sweating, swimming, drying off, or the removal of sunscreen by textiles like beach towels or picnic blankets. Sunscreen should therefore be reapplied every two to three hours or after activities like swimming.

The SPF indicated on the product only specifies protection against UVB rays. Regarding the question of how high the SPF should be: You should use at least an SPF of 30. This is usually sufficient. However, very fair skin tones should opt for SPF 50. Our tip: When in doubt, choose an SPF of 50+. That way you're on the safe side.

Interesting facts about UV radiation and sun protection

Fact 1: UV radiation is higher at mountain altitudes. The intensity of UV radiation increases with altitude. Therefore, in terms of the risk of sunburn and other sun-related injuries, a vacation on snow-covered mountain peaks can actually be "worse" than a beach vacation.

Fact 2: Reflection further intensifies the effect of UV rays. Bright and reflective surfaces such as concrete, sand, water, and even snow reflect the light rays and thus increase the overall radiation exposure that reaches the skin.

Fact 3: Different antioxidants are particularly effective against different types of UV light. For example, vitamin C is especially helpful against UVA radiation, while vitamin E is more effective against UVB.

Fact 4: Makeup with built-in SPF is not sufficient sun protection. The SPF in foundations is usually no higher than 30, if it's even that high. Furthermore, foundation is applied more thinly than sunscreen, which reduces the overall protection factor. In addition, makeup often only protects against UVB radiation, not against the more dangerous UVA rays.

What is the best way to protect yourself?

Sunscreen is essential for prolonged exposure to sunlight. At least SPF 30 is a given, too. However, since the SPF only indicates protection against UVB rays, it's crucial to choose a sunscreen that also protects against UVA rays. Products containing so-called broad-spectrum sunscreens are effective against both types of radiation. To protect yourself against UVA rays as well, you should opt for a broad-spectrum sunscreen. You can identify such products by a special seal. This seal is simply a circle with the word UVA inside. This seal guarantees that the product also protects against UVA rays and that the protection factor against this type of radiation is at least one-third stronger than the protection against UVB.

Sunscreen isn't just important in direct sunlight or for fair skin. You should wear sunscreen regardless of age or skin tone. It's even worth using it indoors or in the car, because, as mentioned, UVA rays penetrate window glass. So, if you spend a lot of time near windows, sunscreen is recommended indoors as well. And even outdoors, you should only go into the shade wearing sunscreen, because UV rays reach your skin whether you're in the shade or in direct sunlight. Read more about how to best protect yourself and enjoy the sun in our article "Summer, Sun, Sunscreen!"