You probably know SPF as a sun protection number, and you may even have heard that SPF 50 only protects 1% more than SPF 30.

In this article I will try to explain what all these numbers mean, how they are calculated - and explain why I think SPF 15 is not enough, but why SPF 50 for a face cream is too much.

What does SPF mean? It is English and stands for Sun Protection Factor: In Danish Sol Beskytselses Faktor.

The SPF number? The SPF number covers how much extra exposure your skin can tolerate beyond normal compared to your skin without the cream. The SPF test therefore uses the time before combustion as a measure. So technically, a cream with SPF 30 will mean that your skin can be in the sun 30 times longer than without sun protection.

To ensure the correct layer, you must adhere to the guidelines on your product according to quantity.

Why several types of solar filter?

Broad-spectrum sun protection is used as we want to be sure that all harmful UV rays are stopped. You may have heard of UVA and UVB, but there are more, but they are not important when we talk about sun protection.

There are not the same rules everywhere in the world, but one thing is certain; all sunscreens must at least protect against UV rays with the most harmful wavelength of 370 nanometers and below. Which means that it must be able to absorb at least 90% of the harmful rays from UV exposure from 370 nm and below.

Broad-spectrum protection therefore means that you are protected as widely as possible for all the harmful lengths of UV radiation.

"I can tell if the sun is burning". Unlike the UVB rays, you cannot feel the sun's UVA rays. They cause neither redness nor burns, but penetrate deep into the skin and cause wrinkles, pigment disorders and many other sun damages, in the worst case, skin cancer.

You actually also get UVA radiation behind a window, just as cloudy days still give UVA radiation. Unfortunately, both types of radiation are a source of skin cancer. It is therefore important to use a broad-spectrum sun factor that protects against both UVB and UVA radiation all year round.

Still in doubt, just look at the pictures you can find of long-distance drivers, where you can actually see the difference between the right and left side of the face. One side which has been exposed to UVA rays and the other side which has not.

How high a sun factor should I use? There is a lot of confusion about how much or how little the individual SPF numbers cover. Many people think that SPF 30 covers twice as much as SPF 15, but there is actually not much difference. SPF 15 protects against 93% of the sun's rays, and SPF 30 protects against 97% of the sun's rays.

It's still quite a lot, of course, but it's changing again. SPF 50 covers only 1% more, namely 98% of the sun's rays. I would therefore think that the amount of sun protection from 30-50 will reduce the space for other active ingredients too much for it to make sense, at least for me, when I think about my own face creams.

Why is there not so much difference between SPF 15, 30 and 50?

Why does SPF 50 cover only one percent more than SPF 30?

It's pure math, but I'd like to try to make sense of it. This calculation is how much your sun protection (SPF) absorbs of the harmful UV rays. It is the number 1 divided by SPF = 1/SPF

The basis is that SPF is the ratio between the amount of UV that your skin can withstand before sunburn, called 1, with the amount of sun filter called SPF. So if amount of sun before sunburn/SPF = how much harmful UV gets through, the rest is the protection you get. Heck, I should have been a mathematician, because now I'm getting confused myself.

But it looks like this:

1-(1/SPF 15) = 0.93 and in percentages it is 93%

1-(1/SPF 30) = 0.97 and in percentages it is 97%

1-(1/SPF 50) = 0.98 and in percentages it is 98%

Why is there a big difference between SPF 15, 30 and 50 anyway? So that's how protected you are. But we can also see how much harmful UV is not absorbed, but gets through to your skin.

Then we are back to it with the number 1 divided by SPF (1/SPF).

SPF 15 = 1/15 and gives 6.5%

SPF 30 = 1/30 and gives 3.3%

SPF 50 = 1/50 and gives 2%

Almost twice as much harmful UV rays penetrate your skin, from an SPF15 to an SPF30. There is therefore good reason to consider which one suits you.

Why not always use SPF50?

In addition to the fact that many people want just a little color in the summer. That many sunscreens either give a white surface or a sticky skin. Then the sun filters take up a lot of space, so in order to make room for other active ingredients, it can be difficult to make an SPF 50 without removing all the other good things in your cream.

The skin also protects itself from the sun's rays. And all SPF claims are based on what normal skin can tolerate. Not from skin with rosacea, eczema or otherwise exposed skin.

Active ingredients such as omega 6, also called GLA, are an extremely important component for your skin's own barriers and protection against UV rays. So a skin without, will be more exposed than a well-treated skin.

I have chosen to follow the advice of the Norwegian Cancer Society. 90% of all Danes lack sunscreen in everyday life and when we finally do, we use too low a sun factor. I have therefore given my face creams both SPF 30 and then boosted them with lots of active ingredients and care.

A composition so that you both have SPF 30, but also everything your skin needs to be optimally protected and optimally cared for.

With RAZspa Face Cream you should feel cared for and protected all year round, you can use RAZspa Face Cream without worry without worrying about anything other than smiling and feeling safe. Find Rich here and Calm here .

What does the Cancer Society say? 90% of Danes lack daily sun protection.

50% of Danes use too low a factor, anything below SPF30, when they finally protect themselves.