Is Sunscreen More Dangerous Than the Sun? The Facts Check

Switzerland is sweltering — and on the balcony, at the lake and in the office, the same question keeps coming up: how much sun is actually still healthy? Right now a stubborn misconception is doing the rounds: in a 2024 survey, one in seven people under 35 believed sunscreen was more dangerous than the sun itself. Time for a calm facts check — no panic, just what science actually knows.

How much sun is healthy?

The sun isn't the enemy. Our body needs UV light to produce vitamin D — essential for bones, muscles and the immune system. The good news: it takes surprisingly little. Exposing your face, hands and arms uncovered for a short time two to three times a week already covers your needs. At a UV index of 7, around twelve minutes is enough for lighter skin types. Hours of «tanning» do nothing more for vitamin D production — they only raise the risk. More sun does not mean more health.

The UV index: summer's most important number

How much protection you need is shown by the UV index, which measures the strength of UV radiation. Rule of thumb: from a value of 3, active protection makes sense. Values of 8 to 11+ count as very high to extreme — typical for high-summer midday hours and for the mountains, where radiation increases with every step in altitude. You'll find the current value for your location at MeteoSwiss or in any weather app. On hot days like these it's in the red almost everywhere.

Myth check: sunscreen

«The chemicals in sunscreen cause cancer.» This is the biggest myth of all. There is no solid scientific evidence that approved UV filters cause cancer in humans. The only proven trigger of skin cancer is UV radiation itself. On the contrary, studies show that people who use sunscreen regularly cut their melanoma risk by about half. It's true that small amounts of certain filters can be absorbed into the body — but harmful effects have never been demonstrated in humans. Switzerland and the EU regulate these substances strictly as a precaution: maximum concentrations have been lowered and some older filters banned outright. The cream on the shelf is therefore well studied.

«Mineral is healthier than chemical.» Both work. Mineral filters (zinc oxide, titanium dioxide) sit on the skin like a mirror, while chemical filters convert the UV radiation. Neither is «toxic» — which cream you choose is a matter of taste, not a health risk.

«Clouds mean nothing happens.» Wrong — up to 80 per cent of UV radiation passes through clouds. You aren't fully protected in the shade or in the water either.

«A high SPF means a carefree day.» Not so. What matters is the amount (most people apply far too little) and reapplying every two hours and after swimming. A high SPF only tempts you to stay in the sun longer.

«Sunscreen stops me getting vitamin D.» Hardly a problem in practice: almost no one applies it so completely and reapplies so often that vitamin D production is genuinely blocked.

Why Switzerland is a high-risk country

Switzerland has one of the highest skin cancer rates in the world. Every year more than 3,000 people develop melanoma (black skin cancer), plus an estimated 25,000 cases of non-melanoma skin cancer. Around 320 people die of melanoma each year. The figures have more than doubled in 35 years — partly because sunburn in childhood and youth raises the risk for life. Sun protection here isn't cosmetics, it's prevention.

Five simple rules for hot days

• Avoid the midday sun: stay in the shade where possible between 11 a.m. and 3 p.m.
• Clothing protects best — together with a hat and UV-protective sunglasses.
• Apply sunscreen generously (a heaped tablespoon for the whole body) and reapply every two hours.
• Protect children's skin especially — sunburn before the age of 18 weighs particularly heavily.
• Watch your moles — have new or changing spots checked by a dermatologist if in doubt.

The conclusion is unspectacular — and that's exactly why it's good: enjoy the sun, but in moderation and with protection. Sunscreen isn't the problem; it's part of the solution.

This article is for general information and does not replace medical advice. If you notice skin changes or have questions about your skin type, please consult a dermatologist.