At first glance it seems quite simple: put on a tube, apply sunscreen, reapply again and again to maintain the sun protection - done! But not all sunscreens are the same.

In detail, five key figures are important:

• Skin's own protection time

• planned duration of sun exposure

• SPF

• UVA

• UVB

Ideally, a product should protect you from both UVA and UVB rays. UVB rays only penetrate the epidermis. However, in high doses they lead to the well-known sunburn. In the worst case, they can chronically damage cell nuclei and thus cause skin cancer. UVA rays have longer wavelengths than UVB radiation and penetrate into the dermis. Although they do not cause sunburn, they can lead to skin changes such as wrinkles, loss of elasticity and irregular pigmentation. Regular and sufficient protection is therefore important.

First let’s talk about the SPF. As a rule, sun protection products are classified according to SPF, i.e. sun protection factor, or SFP (Sun Protection Factor). Here we differentiate between

• low (SPF 6 to 15)

• medium (SPF 15 to 25)

• high (SPF 25 to 50)

• very high level of protection (SPF over 50)

This number indicates the protection of a sunscreen against UVB rays - i.e. the “sunburn-causing” rays, but not the protection against UVA rays! It tells you how long your skin's own protection can be extended by using sunscreen before sunburn occurs.

This can be calculated specifically using the following formula:

Skin's own protection x SPF. As an example: Your skin has a self-protection time of 20 minutes and you use a sunscreen with SPF 10. In this case, 20 x 10 = 200. This means that your skin would be protected by the product for a maximum of 200 minutes.