Sunscreen? How to protect yourself against UV rays

Summer’s coming with its long, sunny days. It’s food for the soul, but not necessarily your skin. It’s true, you need the sun to synthesise vitamin D. In winter, your vitamin D stores are emptied. In spring and summer, they’re replenished, and your body’s own skin protection slowly rebuilds. But too much time outdoors in the sun’s UV-A and UV-B radiation really puts a strain on your skin. So, it’s important to get sun protection right.

Summer vibes: protecting yourself from skin cancer

In a nutshell, sun protection is cancer prevention. And not only in summer, but throughout the year. UV rays reach you even on cloudy days, penetrating the skin and causing damage, especially to your genetic material. Repair cells usually fix the damage, as the German Federal Office for Radiation Protection (BfS) explains.

However, with prolonged exposure and sunburns, these repair systems become overloaded, increasing the risk of skin cancer. The World Health Organization cites UV radiation as the main risk factor for the development of skin cancer. To protect your skin, it’s not enough to apply sunscreen. Ideally, you’ll avoid the sun at midday or wear protective clothing.

Climate change also increases UV risk, with sunny and warm days on the rise. As the BfS reports, this leads to an increase in peoples’ exposure to UV rays.In addition to the many facts about sun protection, there’s also ample fiction. For example, there’s the myth that you can achieve internal sun protection through certain micronutrients. Beta-carotene, a vitamin A precursor, is said to accelerate the sun’s tanning effect on the skin while protecting it from UV radiation from the inside. However, no study has been able to demonstrate this effect.

Light ageing: wrinkles and hyperpigmentation due to sunlight

UV radiation also accelerates our skin’s ageing processes. A recent study examined light ageing in young men between the ages of 18 and 28 and concluded that regardless of age, unprotected sun exposure causes changes in epidermal structure, among other things, and damages collagen fibres, which are responsible for the skin’s elasticity.

UV rays cause oxidative stress in the skin, which accelerates ageing processes. According to studies, longer-wave UV-A rays in particular are suspected of increasing skin pigmentation and thus accelerating light ageing. The study concludes: «It can be stated that DNA damage in the skin is one of the key events in photoaging processes.»

Therefore, it’s a good idea to check the daily UV index provided by Meteoschweiz. It shows the UV radiation throughout Switzerland along with the protection recommended.

Natural sun protection: should you go chemical or not?

Sunscreen should therefore be a part of our skin care routine 365 days a year. But the question of «how» is quite the rabbit hole.

Step one: grab all the half-empty sunscreen tubes from your last summer holiday and throw them in the bin. In 2021, a French-American study came to a frightening conclusion. Namely, in conventional sunscreens that rely on the chemical filter octocrylene, the carcinogenic molecule benzophenone forms after one year. So, stay away from sunscreen with this ingredient. In sunscreen found under the natural cosmetics umbrella, you don’t have to fear this molecule.

Speaking of natural cosmetics, the best choice both for your skin and the environment are non-synthetic sunscreens – in other words, mineral sunscreens that work with physical filters. But even these products aren’t without their own problems. They rely on nanoparticles that reflect UV light, specifically titanium dioxide (a mineral dye) and zinc oxide (a chemical compound of zinc and oxygen). Here’s the snag: titanium dioxide in nanoparticle form fell into disrepute a few years ago after animal studies demonstrated carcinogenic effects. The allegations concern titanium dioxide as a food additive, which was approved until 2022 in products such as mayonnaise, icing and chewing gum. Last year, however, an EU-wide ban on titanium dioxide in food was introduced, not least because it had repeatedly been classified as concerning in studies.

However, this ban doesn’t currently apply to cosmetics and pharmaceuticals. If you’d prefer to avoid nanoparticles in your sunscreen nonetheless, look out for «titanium dioxide», the abbreviation «CI 77891» or «nano» in the ingredients.

Speaking of ingredients, make sure to select a sunscreen labelled as having a UV-A filter. The European Commission recommends that one third of the UV filters in a sunscreen should protect the skin exclusively from UV-A rays. If your sunscreen features the standardised UV-A label on the packaging, it contains the recommended third.

Applying sunscreen correctly – and mistakes to avoid

You might think that applying sunscreen is a no-brainer, but there’s more to it. Here’s what to consider to ensure optimal UV protection:

Mistake #1: using too low SPF

You’ve probably heard of the sun protection factor, or SPF,, time and again, but you might not know how it actually works. The rule of thumb states the higher the SPF, the more UV rays are filtered out of sunlight. If you use SPF 15, about seven per cent of UV rays reach the skin; with SPF 30, about half as much.

The clou: from here on, protection no longer increases linearly alongside the SPF – you can read more on that in this interview with two cosmetic chemists. In other words, SPF 100 is not twice as effective as SPF 50.

You should also choose the sun protection factor according to your skin type. Everyone’s skin has a certain amount of self-protection, which allows you to spend some time unprotected in the sun. For fair skin types, it’s usually limited to just ten minutes. SPF extends this time. The BfS offers the following rule of thumb: if your skin’s own protection is ten minutes and you use SPF 20, you can stay in the sun for about 200 minutes (10 × 20) without getting sunburned.

However, the BfS stresses that this is a theoretical calculation, further stating, «Sunscreens should therefore never be used to extend the period of time spent in the sun arbitrarily. No more than 60% of the theoretical protection time based on the sun protection factor should be utilised.»

For our example above, this means you shouldn’t spend more than 120 minutes sunbathing, even with sunscreen. Math aside, a higher SPF is always better than a lower one regardless of your skin type. In Central Europe, you’ll do well with SPF 50+.

Mistake #2: using too little sunscreen

If you don’t apply enough sunscreen, a high SPF won’t save you. To be exact: in order to achieve the SPF indicated on the packaging, the BfS recommends applying two milligrammes of sunscreen per square centimetre of skin. For an adult, that’s about four heaping tablespoons for the whole body.

To put this into context, a conventional 200-millilitre tube will last you about five applications. So, it’s a good idea to pack more than just one tube for your next getaway.

Mistake #3: applying sunscreen to «problem areas» only

Many apply sunscreen only to the areas of the body that seem particularly susceptible to sunburn, such as the nose and shoulders. You should, in fact, protect your entire body from UV rays – even body parts that may seem absurd at first.

Don’t forget to apply cream the crown of your head, your lips, ears, hands and feet (including the soles of the feet), as well as the skin under the edges of your swimsuit.

Mistake #4: upping protection by frequently reapplying sunscreen

If you reapply sunscreen often, you can stay in the sun longer, right? Unfortunately, not quite. Reapplying sunscreen only maintains sun protection, but doesn’t extend the time you can spend in the sun. It doesn’t make the protective layer any stronger or last longer.

That’s not to say that reapplying sunscreen isn’t important. It is, especially after swimming, sweating or if you rub it off through frequent outfit changes. Reapplication will fill in the spots where the sunscreen has rubbed off. But it won’t extend the calculated protection time, which is counted for the whole day. So, reapplying sunscreen isn’t so much a mistake as an attempt to achieve an effect that’s unachievable.

Mistake #5: using the wrong after-sun care

Sometimes, despite all your care, you may end up with redness or a sunburn. After-sun products are designed to cool and moisturise the skin.

A popular natural remedy is aloe vera. The gel extracted from the plant contains mainly water, a dozen vitamins, important enzymes and amino acids – but it’s doubtful that it really helps the skin as after-sun care. A comparative study explored aloe vera’s possible anti-inflammatory effect – which may explain why, in another study, second- and third-degree burns treated with aloe vera healed faster. Still, other studies found no difference between the use of aloe vera and a placebo.

One thing is certain: no after-sun care can heal the skin damage caused by sunburn. What it can do is support the skin by providing plenty of moisture. You should go for products that absorb into the skin quickly, that is, those with a high water rather than fat content. Oils and fats are too rich for after-sun care; they prevent the exchange of moisture in the skin. In addition, stay away from products with fragrances and preservatives. An evaluation done by German consumer magazine ÖkoTest (link in German) revealed this includes many classic brands.

If you want to be completely on the safe side, you can make the ideal care product for your skin right at home. In fact, quark or yogurt is often enough to soothe skin that’s reddened or lightly sunburnt.

Important: if your skin is more severely burnt with any blisters or open wounds, stay away from dairy products as after-sun care! The bacteria can penetrate the wound and lead to an infection. If you’ve got severe sunburn, don’t treat it yourself – seek out a doctor.