Sunshine – as much as we enjoy it, it is responsible for up to 80% of our skin aging. Until recently, it was believed that only the higher energy UVB rays could cause skin cancer and sunburn. However, recent studies have shown that the lower-energy UVA rays penetrate deeper into the skin. Therefore, UVA radiation is now also held responsible for the development of melanomas, as well as for the formation of wrinkles and skin irritation. In the following, we will try to explain what UV radiation triggers in the skin skin and how you can enjoy the sun with a little more peace of mind.
What is UV radiation?
UV light is electromagnetic radiation and is not visible to the human eye. It reaches the earth via solar radiation and is divided into three wavelengths:
- UVA (highest wavelength, penetrates into the human subcutaneous tissue and causes cell damage)
- UVB (medium wavelength, penetrates into the human epidermis and causes sunburn)
- UVC (smallest wavelength, does not make it all the way to the earth)
Why is UVA radiation so dangerous?
- While UVB radiation occurs mainly on sunny summer days, UVA is constantly present, 365 days a year
- UVA radiation is only partially blocked by clouds or glass
- about 40% of the UVA radiation outside, arrives in the building / car etc.
- UVA penetrates into the lower layers of the skin
- In its spectrum, the light is harmful to the skin because free radicals are formed that attack proteins, lipids and DNA
How does UV radiation affect human skin?
The skin can protect itself by automatically thickening the horny layer (stratum corneum) through the accelerated rate of cell division during prolonged sun exposure. Stimulated by UVB rays, melanin (pigments) are formed in the epidermis, which help protect the skin. UVB rays also stimulate the formation of vital vitamin D in the skin.
However, this self-protection is limited and UVA and UVB can destroy the chemical bonds if you spend a long time in the sun. This in turn, can lead to cell death, vascular dilatation in the subcutaneous tissue and damage to the DNA and can, for example, damage collagen or elastin fibers in the skin and thus lead to premature skin aging. Sun or age spots can also appear.
The formation of free radicals also increases the risk of skin cancer.
What are Free Radicals?
Free radicals are ‘damaged atoms’, unstable molecules that are missing an electron. The body creates free radicals in response to external or internal stress. The formation is triggered, among other things, by UV exposure, smoking or inflammation.
What is Oxidative Stress?
If the body cannot process or remove the free radicals effectively, this can lead to so-called oxidative stress, which can damage cells and body functions and, among other things, induce premature skin aging.
Sun protection should therefore be part of daily skin care.
In addition to numerous different types – from cream to lotion, from gel to spray – a distinction is made primarily according to the mode of action of the sunscreens.
There are two major categories of sunscreens:
- Mineral UV filters
- Chemical UV filters
What are mineral UV filters and how do they work against sun rays?
Mineral filters usually consist of tiny particles of metal oxides that form a protective layer on the surface of the skin and reflect UV radiation like tiny little mirrors. Because UV radiation is reflected or scattered, it cannot penetrate the deeper layers of the skin.
Mineral filters are white, especially in the case of higher SPFs. They have also been available as nanoparticles for a number of years.
Benefits
- Do not penetrate the skin -> generally do not trigger any allergic reactions
- Well tolerated by small children
- Work immediately after application
- Mineral pigments are chemically stable and do not form any disadvantageous reaction products
Disadvantages
- “Whiten”
- Thick consistency that doesn’t absorb well
- Must be reapplied after bathing or sweating heavily
- Usually only achieve a sun protection factor of up to SPF 30
What are chemical UV filters and how do they work against sun rays?
Chemical UV filters absorb into the skin and together with it form the protective film. Unlike mineral filters, they do not reflect harmful rays, but absorb them and convert them into harmless energy (infrared light and heat).
The way it works is a little more complicated: in the electron shell of the UV filter, the electrons float around the atomic nucleus and establish bonds with other atoms. Penetrating light with its UV rays can loosen such bonds of electrons and rearrange the electrons without the atoms involved flying apart in all directions. The compound goes into an “excited state”. Because “internal resistance” has to be overcome in the electron shells, some energy is lost. When returning to the initial state, the compound does not emit UV light again, but radiation with less energy: harmless infrared light and ultimately heat.
Chemical UV filters also have advantages and disadvantages:
Benefits:
- Still work after bathing
- Do not form a film on the skin
- Don’t “whiten”
- Achieve higher sun protection factors than mineral filters
- Low allergy potential
Disadvantages:
- They only develop full effect after 20 to 30 minutes
- They are often not photostable, i.e. they deteriorate when exposed to UV light. This is why stabilizers must be added to the sunscreen, which in rare cases can trigger allergic reactions.
- Potentially have poor biodegradability. It has not yet been established whether and what damage to the environment is caused through these sunscreens.
Natural UV filters: how does the UVA protection in the Yellow Serum work?
There are also UV filters in nature. A particularly effective one comes from the alga porphyra umbilicalis. This alga grows near the shore and is exposed to extreme weather with very high solar radiation. Over millennia, this alga has adapted to its environment and now features so-called MAA: mycosporin-like amino acids (microbial sun filters).
MAAs have effective antioxidant molecules. Similar to how a chemical UV filter works, these antioxidant molecules make it possible to stabilize free radicals in their ring structure.
All MAAs absorb ultraviolet wavelengths, typically between 310 and 362nm. This helps protects the DNA from UV damage.
What are Antioxidants?
Antioxidants are substances that can stop or slow down cell damage caused by free radicals. They release one or more of their electrons to free radicals in order to stabilize them and are therefore also referred to as ‘radical scavengers’.
Conclusion: what should be considered when using sun protection?
Sun protection is becoming more and more important and should therefore be part of daily facial care.
When it comes to sunbathing in particular, studies have shown that most people do not apply enough sunscreen: on average, an adult needs at least 35ml of cream to properly protect their entire body.
Regarding the right product, you should orientate yourself on your individual skin type.
In general, it is important to avoid excessive sunbathing and to use combinations of different sun protection: textiles (with clothing and
headgear) + sunglasses + sunscreens.
Caution also applies on cloudy days, because UVA rays penetrate the cloud cover.