Waarom je écht 365 dagen per jaar SPF moet smeren

Why you really should apply SPF 365 days a year

Apr 22, 2022Joëlle Lochtman

A big misconception is that sunscreen is only important to use in the spring and summer. In short, when the sun really shines. Nothing is less true. SPF – stands for Sun Protecting Factor – you need 365 days of the year. Even if it's raining, or if you're indoors all day. Small side note, SPF only provides protection against UVB rays, it says nothing about UVA rays. The latter is calculated in a different way.

Earlier we wrote a blog about the different filters that can be in your sunscreen. Also read this for helpful tips.

Uv-A and Uv-B rays

The sun gives off two types of UV rays: A and B. You can see and feel the effect of UV-B rays. They affect the skin's surface, causing you to burn. These rays can also cause invisible damage, such as various skin abnormalities. UVA rays affect your skin on a deeper level. They penetrate in such a way that they damage vital parts of your skin that you need to keep your skin fresh and healthy. Due to the damage that UVA rays cause, you get wrinkles faster. We'll break it down for you.

UV-B rays:

  • Cause immediately visible damage to your skin.
  • Are at their brightest between 10 a.m. and 4 p.m. and as you get closer to the equator.
  • Do not work through glass.

UVA rays:

  • Make your skin tan. Sounds positive, but tanning is also a sign of damage to your skin from the sun.
  • Are equally strong all day long. It doesn't matter what time it is and how close you are to the equator.
  • Also penetrate glass.

Both rays can cause skin cancer. It is therefore important to apply SPF with a 'broad spectrum' (= protection against both rays) every day (preferably several times a day).

Various factors

For a long time it was thought that the SPF factor you put on was equal to a few minutes. So SPF 30 equaled 30x10 minutes = 300 minutes of protection. Unfortunately this is not quite correct. It is difficult to calculate exactly what kind of protection a factor offers. It depends on many different elements, such as the time of day, the time of year, and how close you are to the equator.

It is therefore only a blockage for UV-B rays. Roughly speaking, SPF 15 blocks about 93% of UV-B rays, SPF 30 almost 97% and SPF 50 blocks 98%. SPF 30 therefore allows about 3% to pass through, which is equal to 1/30and, while SPF 50 allows about 2% to pass through, which is equivalent to 1/50and† Lubricating a higher factor also comes with a disadvantage. The chance of a sensitive reaction is greater.

We offer for everyday use the SUN15 from Squalan designed for sensitive skin. Our advice: generously apply the cream two or three times a day to your face, neck and décolleté.

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