Updated November 2026
The short answer: sunlight is the biggest outside cause of skin ageing. One widely cited study of more than 300 women (Flament et al., 2013) linked about 80% of visible facial ageing signs to UV exposure. The good news is that, unlike your genes, it's something you can protect against every day.
How the sun ages your skin
The sun sends out several kinds of radiation. Two types of UV reach our skin:
- UVB mostly stays in the outer layer of the skin (the epidermis). It causes sunburn and damages the DNA of skin cells.
- UVA goes deeper, into the dermis. There it breaks down collagen and elastin, the fibres that keep skin firm and elastic, and creates free radicals. UVA is present all year and passes through clouds and window glass.
Visible light, especially high-energy blue-violet light, also plays a role in dark spots and melasma. Learn more in HEV, blue light and visible light.
Doctors call sun-induced ageing photoageing. To see the difference, compare the skin on your face or the back of your hands with the skin on the inside of your upper arm. Both are the same age, but only one gets regular sun.
The 4 main signs of sun ageing
1. Wrinkles and fine lines
As UV breaks down collagen and elastin, the skin slowly loses its firmness and bounce. Lines appear earlier and deeper, especially around the eyes, mouth and forehead. The well-known photo below shows a truck driver whose face is far more wrinkled on the side that faced the window for decades. UVA came through the glass every working day.
2. Dark spots and uneven skin tone
UV stimulates melanin, the pigment that gives skin its colour. Over time this leads to sun spots (often called age spots), freckles that don't fade and hyperpigmentation. Twin studies show it clearly: in the photo below, identical twins with the same genes look years apart. The sister on the right spent much more time in the sun without protection.
A daily SPF helps prevent new sun-induced spots. Our Daily Protection Hydrating Day Cream SPF 30 combines hydration with broad-spectrum protection, and tinted formulas with iron oxides add protection against visible light.
3. Sagging skin
UV both speeds up the breakdown of collagen and slows down new collagen production. The skin loses its support, which shows first on the cheeks and along the jawline.
4. Rough, dull texture
Long-term sun exposure disrupts the skin's natural renewal. Skin can become thicker, rougher and less radiant, which makes it look older than it is.
Tanning beds age skin too
Sunbeds mainly use UVA, often at higher intensities than midday summer sun. They speed up wrinkles and pigmentation in the same way, and they raise the risk of skin cancer. There is no "safe tan" from a solarium.
More than looks: skin cancer
UV exposure is also the main risk factor for skin cancer, including melanoma, basal cell carcinoma and squamous cell carcinoma. More than 100,000 cases of melanoma were registered in the European Union in 2020, with over 16,000 deaths that year. Denmark, the Netherlands, Norway and Switzerland are among the countries with the highest melanoma rates in the world. In Switzerland, experts estimate that 20,000 to 25,000 people are diagnosed with some form of skin cancer every year, most often basal cell carcinoma.
Read more in Protecting your skin: the facts about skin cancer.
How to protect your skin from sun ageing, every day
- Use a broad-spectrum SPF 30 or higher every day, not only on holiday. Look for the UVA circle on the label.
- Apply enough. Most people use too little. You need about a teaspoon for the face and neck. Here's how much sunscreen your face really needs.
- Keep going in winter. UVA doesn't take the winter off, and snow and altitude make UV even stronger. See why UVA protection matters in winter.
- Top up during the day. A mineral SPF 50+ powder lets you refresh your protection over makeup.
- Choose tinted protection if you get dark spots. The Daily Protection Liquid Foundation SPF 50+ combines high SPF with light coverage.
- Add shade, a hat and sunglasses around midday in summer.
Other habits that help
- Sleep: your skin repairs itself overnight.
- Exercise: better circulation brings oxygen and nutrients to the skin.
- No smoking: smoking narrows blood vessels and speeds up skin ageing.
- Less sugar: too much sugar promotes glycation, which stiffens collagen.
Frequently asked questions
Can sun damage be reversed?
Partly. Once you protect your skin consistently, it can repair some of the damage, and dermatologists can treat pigmentation and fine lines, for example with retinoids or laser treatments. Prevention is still far easier than repair, and anything that changes, bleeds or looks unusual should be checked by a dermatologist.
Is SPF 30 enough to prevent ageing?
A broad-spectrum SPF 30, applied generously every day, already blocks most UV. SPF 50 gives an extra margin if you apply less than the test amount or spend a lot of time outdoors. More in what SPF 50 really means.
Does sun ageing happen through windows?
Yes. Ordinary window glass blocks most UVB but lets much of the UVA through, which is the type mainly responsible for ageing.
Conclusion
The sun is the biggest outside factor in how fast your skin ages, and the one you have the most control over. Daily broad-spectrum SPF, all year round and in a generous amount, is the most effective anti-ageing step you can take. Good sleep, no smoking and a balanced diet help your skin stay healthy too.
