All clothing provides minimal UV protection. Even a light fabric covers the skin and therefore acts as a barrier against the sun. However, not all fabrics have equal protection.

A classic white cotton t-shirt will have low UV protection(UPF UV protection factor 5 to 7 according to the Skin Cancer Foundation). This means that, 20% of UV is not filtered by the t-shirt. A burn can therefore occur quickly.

Below is an example of a test performed with ultraviolet rays capable of causing burns after approximately 10 minutes.

Worse yet, when wet, the protection level drops to around UPF 3, exposing us to UV rays we are unaware of (33% of UV is not filtered out). We can therefore get a sunburn in less than 30 minutes.

At Ker-Sun we offer anti-UV clothing to guarantee you optimal protection for all your activities.

See our anti-UV clothing

What technical characteristics should a garment have to protect against UV rays??

First of all, it is important to remember that only a certified test will tell what the real level of protection of a fabric is. To obtain a fabric with optimal sun protection, several elements come into account:

  • The construction: the tighter the threads and the denser the construction, the higher the UV protection. The downside is that the fabric is less breathable and therefore warmer
  • The composition of the threads: some materials such as polyester absorb UV rays better than other materials such as linen or cotton
  • The weight : The heavier and thicker the fabric, the more it will protect against UV rays, however you may be warmer
  • The colour : Dark or bright colors prevent UV rays from reaching your skin by absorbing them rather than letting them in. This is why these colors offer better protection than the lighter shades.
  • The presence or absence of additives: Some fabrics have additives that reduce the penetration of UV rays
  • Use : a fabric that is wet, distended or aged will often see its protection against UV rays diminished

Some traditional ready-to-wear clothes can therefore completely protect against UV rays (eg thick black jeans), however there is a good chance that they are not suitable for use in hot weather, to go in the water or for sports. Conversely, light clothing that is not specifically designed to protect from the sun will surely have low UV protection.

To protect yourself from the sun, we therefore recommend using clothing designed for this. Manufacturers will normally find a balance in the different characteristics of the fabric, to offer you optimal UV protection, but also good breathability and super comfort.

See our selection of anti-UV clothing

How to know the UV protection level of a garment?

The first recommended point to know the level of UV protection of a garment is to look at its level of protection (if indicated). There are several standards that exist and the most used is the UPF standard (meaning UV Protection Factor). It makes it possible to define the proportion of ultraviolet rays stopped by a fabric. For example UPF 25 means that the fabric allows 1/25 of the radiation to pass.


Protection category

% of UV blocked

UPF 15 244


93.3 95.99

UPF 25 399

Very good

96.0 97.44

UPF 40 50++


97.5 98++

NB: Between UPF 0 and UPF 15: the garment cannot be considered to provide adequate UV protection.

In addition, well-designed anti-UV clothing will be made from technical fabrics to suit the use for which it is designed. If it’s an urban or travel summer garment, then it will likely have a fabric designed to be comfortable, soft, cool and light. If it is an aquatic garment, the fabric will dry quickly and be resistant to chlorine and salt. If it's for playing sports, the fabric will be light, very breathable, and will wick away moisture.

However, in making a good UV-resistant garment, fabric isn't the only factor. The style and design of the garment are also important. Indeed, a classic short-sleeved t-shirt will protect you much less well than a long-sleeved t-shirt with sleeves and a slightly raised collar.

At Ker-Sun we have selected the best anti-UV clothing to protect you during each of your activities.