Your mother was right: slathering yourself in sunscreen is incredibly important. But how exactly does sunburn, and therefore sunscreen, work? We love to give you tips and advice. Good sun cream brands, But what do these products actually do? Oh dear, if you understand that, you'll be applying extra moisturiser from now on!
What really happens when you get burned
Sunburn is actually quite a strange thing. When it happens, you often don’t notice a thing. You’re relaxing on the beach, sitting on a terrace or strolling through the city. It’s only hours later that your skin becomes red, hot and painful. Nooo. But what happened in the meantime? To understand that, we first need to look at UV radiation. Dermatologist Jorrit Terra from Isala Dermatological Centre/UMC Groningen explains in a video by the University of the Netherlands that there are three types of UV radiation: UVA, UVB and UVC. Yes, there really are three types of radiation! But fortunately, we needn’t worry about the latter, as it is blocked by the ozone layer. UVA and UVB do reach our skin, however. According to the dermatologist, approximately 95% of the UV radiation that reaches us consists of UVA, with the remaining 5% being UVB.
The difference between the two is easy to remember, he explains. ‘The A in UVA stands for Ageing (ageing). This radiation penetrates deep into the skin and affects, among other things, collagen. This leads to wrinkles and sagging skin in the long term. Moreover, UVA passes through glass. So you are not automatically protected behind a window. The B of UVB stands for burning (burning). This radiation penetrates slightly less deeply into the skin, but it does damage the DNA of skin cells.’ And that’s precisely where sunburn begins. As soon as skin cells become damaged, your body tries to repair that damage. Damaged cells are removed and an inflammatory response begins. Blood vessels dilate and extra blood flows to the damaged area. This causes that familiar red, warm, and painful skin. Ouch. So, the burning you feel in the evening is actually your body's reaction to damage that often occurred hours earlier.
Your skin remembers every sunburn.
We all know that sunburn hurts. But the annoying thing is that the damage doesn't always disappear once the redness has faded. Every time you get burnt, skin cells are damaged. Fortunately, your body can repair a lot of that damage. But it doesn't always succeed. Sometimes damaged DNA is left behind. We call that a mutation: a change in the DNA of a cell. On its own, that's not an immediate problem. Our bodies clear out damaged cells daily. But the more often you get burnt, the more DNA damage can build up. And the more damaged cells there are, the greater the chance that one will eventually slip through the net. Both UVA and UVB radiation play a role in the development of skin cancer. That's why dermatologists often say that your skin has a good memory. That one sunburn on holiday might seem long forgotten, but your skin definitely remembers it. And that's precisely why it's sensible not to wait until your skin turns red, but to prevent damage as much as possible.
Why getting used to the sun only helps marginally against sunburn
After all the talk about DNA damage and skin cancer, one might almost forget that sunlight also has benefits. For example, it helps our bodies produce vitamin D, which is important for strong bones and muscles. Many people also feel happier when the sun is shining. Fortunately, your skin is not entirely defenceless against UV radiation. As soon as you get more sun exposure, your body tries to protect itself. Skin cells start dividing more rapidly, causing the skin to thicken slightly. In addition, pigment cells produce extra pigment. That is the process by which you tan.
This pigment acts as a sort of natural protective layer. It forms small caps above the cells in your epidermis and absorbs some of the UV radiation before it can cause damage. Handy, but unfortunately not enough. A tan doesn't mean you're protected against sunburn. Your skin tries to limit the damage, but it can't win that battle alone. You can see this reflected in the differences between people too. While one person turns red after lunch on a sunny terrace, another seems able to sit in the sun for hours without burning. How does that actually work?
Why one person burns faster from the sun than another
The reason one person burns faster than another has everything to do with pigment. In another video from the Universiteit van Nederland, dermatologist Göran van Rooijen from Erasmus MC explains exactly how that works. ‘In the top layer of the skin are special pigment cells, known as melanocytes. They produce pigment that helps protect the skin from UV radiation. You can think of that pigment as tiny parasols hovering above the skin cells, blocking some of the harmful radiation. Strikingly, people with light and dark skin have approximately the same number of these pigment cells. The difference lies mainly in how active they are. People with dark skin produce more and darker pigment. As a result, they naturally have more protection against the sun.’
Dermatologists distinguish between six skin types. People with skin type one, very light skin, often burn quickly and hardly tan. At the other end of the spectrum is skin type six, very dark skin with more natural protection against UV radiation. Yet, no skin type is completely protected. People with dark skin can also suffer skin damage and develop skin cancer. The main difference is that people with light skin burn more easily because their natural protective layer is less strong. And because sunburns are what cause DNA damage, people who burn more often ultimately also run a higher risk of skin cancer.
Everyone can get sunburned, even people with darker skin who naturally produce more protective pigment. However, people with lighter skin generally get sunburned faster and more often, which increases their risk of skin cancer.
Zonnebrandcrème werkt door de bescherming van je huid tegen schadelijke ultraviolette (UV) stralen van de zon. De meeste zonnebrandmiddelen bevatten chemicaliën die UV-stralen absorberen voordat ze je huid kunnen beschadigen. Sommige zonnebrandmiddelen bevatten ook mineralen zoals zinkoxide of titaniumdioxide, die een fysieke barrière vormen om UV-stralen te blokkeren en terug te kaatsen. Er zijn twee soorten UV-stralen die de zon afgeeft: UVA en UVB. * **UVA-stralen** worden geassocieerd met huidveroudering, zoals rimpels en vlekken. Ze kunnen ook bijdragen aan huidkanker. * **UVB-stralen** zijn de voornaamste oorzaak van zonnebrand. Ze spelen ook een rol bij huidkanker. Zonnebrandcrème bevat bepaalde ingrediënten die deze stralen absorberen of weerkaatsen. De beschermingsfactor (SPF) op de verpakking van zonnebrandcrème geeft aan hoe goed het je beschermt tegen UVB-stralen. Een hogere SPF betekent betere bescherming. Het is belangrijk om zonnebrandcrème royaal aan te brengen op alle blootgestelde huid, minstens 15-30 minuten voordat je in de zon gaat. Breng het ook opnieuw aan elke twee uur, en vaker als je hebt gezwommen of gezweet.
Fortunately, we don't have to rely entirely on our skin's natural protection. That's where sunscreen comes in. Sunscreen creates a protective layer on the skin. When UV radiation hits it, a large portion of that radiation is absorbed before it can penetrate deep into the skin and cause damage. The less UV radiation that reaches your skin, the smaller the chance of DNA damage, sunburn, and skin ageing.
There are quite a few misunderstandings about sunscreen. For example, you regularly hear that some sunscreens ‘contain a lot of chemicals’. That might sound scary, but it doesn't actually say much on its own. Everything around us consists of chemical substances. Water is a chemical substance. And some completely natural substances can actually be toxic. Who would willingly take a bite out of a poisonous mushroom or a sip of snake venom? Exactly. ‘Natural’ does not automatically mean safe, just as ‘chemical’ does not automatically mean dangerous. Ultimately, what matters is that sunscreen does what it's intended for: protecting your skin against UV radiation. Because by now, we know what that radiation can do. From accelerated skin ageing to DNA damage that your skin carries for years. A good layer of sunscreen cannot undo that damage, but it can help prevent it. Here's how to choose your SPF in a more eco-friendly way!
Wanneer verbrand je het snelst?
How quickly you burn depends mainly on the sun's UV index. This indicates how much UV radiation reaches the Earth's surface. In the Netherlands, the UV index roughly ranges from 0 to 8, but it can be much higher at holiday destinations. The UV index is determined, among other things, by the position of the sun. The higher the sun is in the sky, the shorter the path UV radiation has to travel through the atmosphere. That's why the sun is usually strongest between 12:00 and 15:00. At that time, you also run the greatest risk of burning. But the UV index doesn't just depend on the time of day. The quality of the ozone layer, air pollution, and cloud cover also play a role. And then there's something many people don't think about: UV radiation can reflect. Water, sand, and even snow reflect sunrays, meaning your skin also absorbs extra radiation from below. A day at the beach is therefore often more deceptive than you think.
This is how to protect yourself well from sunburn
Hopefully, after reading this article, you'll understand why dermatologists emphasise the importance of proper sun protection. Sunburn is much more than a temporary red complexion; it's visible skin damage. This doesn't mean you should avoid the sun. Sunlight also has benefits, and an afternoon outdoors is often good for your mood. However, it is wise to be smart about sun exposure. Therefore, apply sunscreen at least 15 minutes before you go outside, preferably choose SPF 30 or higher, and reapply regularly. Seek shade more often during the hottest part of the day and consider wearing UV-protective clothing on sunny days.
Also pay extra attention to water and sand. These can reflect UV radiation, causing you to unknowingly absorb more sun than you think. And perhaps the most important reason to apply sunscreen: skin cancer is now the most common form of cancer in the Netherlands. According to the KWF, over eighty thousand Dutch people received this diagnosis in 2025. The main cause is excessive UV radiation from the sun or sunbeds. So yes, your mother was right when she used to chase you with that tube of sunscreen. Slathering it on is annoying and a freshly greased body isn't necessarily the height of comfort (sticky!), but it is one of the wisest things you can do on a sunny day.
Sources: University of the Netherlands, University of the Netherlands Instagram, KWF.nl. Photo credits: Kaboom Pics, Pexels (main image), other: Hanna Pad, Pexels (light skin), RF..studio, Pexels (girl applying cream), Julia Kuzenkov, Pexels (girls in the sea).
