The science behind UV protective substances: How does the protection work?

What is UV radiation and why is it dangerous?

Ultraviolet radiation (UV radiation) is a component of sunlight that is invisible to the human eye. It is divided into three main types: UVA, UVB, and UVC. While UVC rays are mostly blocked by the Earth's atmosphere, UVA and UVB rays reach the Earth's surface in relevant amounts – and thus also our skin.

UVA rays penetrate deep into the skin layers and can cause long-term damage there, such as premature skin aging or impairment of the immune system. UVB rays are more energetic and penetrate the skin less deeply, but are primarily responsible for sunburns and the development of skin cancer. Both types of radiation can also damage materials such as plastics, textiles, or paints and accelerate their aging.

Especially during outdoor activities, at higher altitudes or in regions with high solar radiation, protection from UV radiation is essential. Climate change and the associated alteration of the ozone layer are also causing UV exposure to increase in many parts of the world. Effective UV protection is therefore not just a matter of comfort, but a contribution to long-term health care.

How do UV-protective fabrics work on a molecular level?

UV-protective fabrics rely on physical and chemical mechanisms that prevent UV rays from reaching the skin. There are basically two ways fabrics block UV radiation: through reflection and scattering or through absorption.

Physical protection usually involves tightly woven materials whose structure reflects or scatters UV rays before they can penetrate deeper skin layers. The denser the fabric, the more difficult it is for radiation to pass through. Matte or coated surfaces can also help to deliberately deflect UV rays.

Chemical protection works through special substances that are embedded in or applied to the fabric. These absorb UV radiation on a molecular level and convert it into harmless heat. Compounds such as titanium dioxide or zinc oxide, known for their excellent UV absorption, are commonly used for this purpose.

An efficient UV-protective fabric often combines both mechanisms. What matters is not just the material itself, but also the processing, weave density, color, and even moisture content – because wet fabrics often let more UV radiation through than dry ones.

What do UPF ratings mean for textiles?

The “Ultraviolet Protection Factor” (UPF) is the measure of UV protection a textile provides – comparable to the Sun Protection Factor (SPF) in creams. A textile with a UPF of 50 means that only 1/50 of the UV radiation reaches the skin, i.e., only two percent. The rest is absorbed or reflected by the material.

A higher UPF value indicates better protection. While regular cotton clothing often has a UPF of 5 to 15, specially developed UV-protective textiles achieve values between 30 and 50+. In many countries, international testing standards such as the Australian/New Zealand Standard AS/NZS 4399 or the European standard EN 13758 are used to measure protective performance under controlled conditions.

Unlike SPF, which must be applied and regularly renewed, high-quality textiles with a high UPF value offer lasting protection as long as they are properly cared for and not damaged. This makes it easy to integrate sun protection into everyday life – whether when hiking, swimming or in everyday life.

Materials and technologies in UV protection: What’s in the clothing?

Not every fabric automatically provides UV protection. Materials like polyester and nylon are considered particularly UV-resistant due to their dense molecular structure. Cotton can also offer UV protection, especially when it is tightly woven or treated with special substances.

Common technologies include microfibers with UV-blocking pigments, titanium dioxide coatings, or integrated UV absorbers. Some manufacturers use special weaving techniques or yarn types that naturally offer higher protection. Dark colors also absorb more UV rays than light ones, which is why color choice plays an important role.

In recent years, sustainable UV-protective fabrics have become increasingly important. These are textiles made from recycled materials or produced using environmentally friendly processes – without compromising the protection factor. This development combines functionality with responsibility and specifically appeals to environmentally conscious consumers.

Tips for choosing and caring for UV-protective clothing

When buying UV-protective clothing, you should look for certified UPF values. Terms like “UV protection” alone are not protected – only standardized testing and labeling with the UPF value provide information about the actual protective performance. Also look for tightly woven fabric, long sleeves, and a good fit, especially for children's clothing.

Care also affects UV protection. Wash UV clothing as gently as possible, ideally at low temperatures and without bleach. Some textiles lose their protective performance after frequent washing, while others – especially those with integrated UV absorbers – retain their protection even after many washes. The manufacturer’s care instructions provide information on this.

Avoid excessive stretching of the fabric, as this can weaken the structure. Wear and tear, sunscreen, or chlorinated water can also reduce protection over time. Regular visual inspections for wear or damage help to maintain protection in the long term.