In the  blog series to UV rays, sunscreen  and premature  skin aging , I would like some aspects « around a sun protection cream » point, which are not yet anchored in the minds of consumers. Especially it comes to the importance of UVA protection in every day care with sun protection factor (SPF, SPF = UVB) emphasized. Because sunscreens are still assessed primarily from the point of their SPF factor or recommended. The UVA protection performance is then often completely neglected.

What do you expect in the blog series for sun protection? I will address the following questions:

  1. What is the difference between UVA and UVB?
  2. What UVA filters are available and which ones are stable?
  3. How is the UVA value measured? What’s PPD, PA and UVA-PF?
  4. If  UVA radiation regardless of weather, season and distance from the equator?
  5. Penetrates the UV light through the window?
  6. What is the role of Antioxidants in protection against photoaging?
  7. Is Makeup with SPF useful?
  8. Can a  Foundation be used in a sunscreen?
  9. How much sunscreen you have to actually apply?
  10. What is the difference between mineral (organic) and chemical (inorganic) sunscreen?
  11. Can a serum to be applied under a sunscreen?
  12. How long you have to wait for the order from a center of the Sun?


Meanwhile, many research results show that the sun’s rays the cause of premature skin aging no. 1 are (Source 1). Ie the UV light is more harmful than about smoking for our skin.

For our purposes, is now to be made between UVA and UVB rays:

UVB (short-wave radiation from 290 to 320 nm) are responsible for the tan and a possible sunburn (ie: relatively quickly visible). The UVB rays play a key role in the development of skin cancer. While contributing to skin aging, but not to such a high extent as the UVA.

  UVA namely (long-wave radiation from 320 to 400 nm) do not cause sunburns, but carry cumulative sun-damaged skin, and premature skin aging at.

The reason is that UVA rays penetrate into the deep skin layer (dermis), where the proteins collagen break down and elastin and accelerate the development of free radicals.

Premature aging is the result. Many studies are now assuming that free radicals are generated primarily from the UVA radiation. The consequence are  wrinkling and loss of facial volume (photoaging and atrophy) in both skin layers: epidermis and dermis (see the picture below, source:. ).

uv lights

One of the latest study source 2 (2014, here source 3 a summary of results) has shown that molecules were formed after two UVA exposure (only two hours) that the collagen degradation contribute!

sun on skin

A day cream without a UVA protection makes the anti-aging perspective no sense at all; may she kilos of antioxidants to fight free radical!


Many is largely unknown that the UVA rays our skin bomb from sunrise to sunset . They are easy during the day « because » – regardless of the weather, time of day and distance from the equator. While UVB rays vary widely, for example, are most at lunchtime, the UVA radiation throughout the day remains more or less constant distributed.

As the website of the Skin Cancer Foundation is running: « They [UVA] are present with Relatively equal intensity during all daylight hours Throughout the year, and can penetrate clouds and glass. » ( Source )

So as the UVA light penetrates through clouds, a sunscreen with a high UVA protection even during a cloudy or rainy day is to wear. A sunscreen is your secret weapon against premature skin aging! Sounds like an advertising slogan; but is true!


Even if a life is happening mainly between the home, office and supermarket, the skin will continue to be delivered the damaging effects of the sun without a UVA protection. While UVB rays are largely blocked by a glass, the UVA radiation penetrates to 75% through the window ( source 4 ). This means that even if you do not move much in the open, you get Although not burn, but an extra helping of sun damage.

A good UVA protection should indeed every day and also indoors be worn. A stronger sunscreen in summer (vacation) or to wear at lunchtime, only makes sense if you have avoiding sunburn goal, but not a premature skin aging.


The number of sun protection factor (SPF) (eng. SPF : sun protection factor ) refers only to protection against UVB rays! ( Here source 5 can you read how the SPF number is created and as the sun protection factor is calculated).

In fact, the UVA issue has been neglected for a long time. But today we know with certainty about the consequences of UVA radiation. The ignorance of many beauty journalists and pharmacists is therefore incomprehensible. I am always amazed at how many self-proclaimed beauty gurus advise that « in the summer sure to wear a sunscreen of 50 » without mentioning the UVA aspect.

Hopefully this will change with the recommendation of the European Commission. Accordingly, the intended UVA protection factor of at least one third of the total light protection , respectively. Thus, the SPF number is not completely negligible, because the UVA protection proportion now fall disproportionately to the SPF factor.   As the UVA protection is measured, you can read in full detail here.

So: The focus solely on the basis of Lichschutzfaktors is secondary from the perspective of photoaging (not more)! Because with the level of SPF / UVB protection increases the likelihood that the UVA protection will be higher.


Unfortunately it’s not that easy. It depends on,

1) whether the UVA filter photostable and are

2) whether the  whole UVA-wave spectrum cover (up to 400mm).


Finally, I would like to introduce to you the result of studies demonstrating the  anti-aging effects of sun protectionis:

A group of 903 Australians were divided into two groups. The group I was not wearing sunscreen, while the Group II wore every day a sunscreen with a protection factor SPF of at least 15 (unfortunately I found no indication as to the role played by the fact of UVA -protection. I assume that each is to broad spectrum sunscreens negotiated). After 4.5 years, the second group was 24% less skin damage compared to Group I ( more here, source no. 4 ).

In addition, confirmed the study that the premature aging of the existing skin damage was independent. The only relevant difference feature was a large draughty order from sunscreen. 

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