Protection factor and phototypes

What does sunscreen prevent? Which is the most suitable? How long can they protect the skin? Do they reduce sunburn? What does the numerical scale with which they are measured mean? The correct use of sunscreen requires knowing the answers to these questions and, in particular, the phototype and sun protection factor (SPF) of the product being used.

There are two indices that indicate protection. Sun Protection Factor (SPF) or Protection Index (IP) refers to protection against ultraviolet B (UVB) rays. The second index, called PPD, refers to the level of protection against ultraviolet rays A (UVA).

Phototype

Choosing a sunscreen requires knowing the phototype, which is the skin's ability to cope with sunlight. There are six phototypes in total, depending on skin color, hair color, and tanning ability. The most frequent phototypes in the Spanish population range between two and four.

These two types of rays affect the skin in different ways. UVBs are responsible for immediate tanning, burns, skin damage (cancer, blemishes or lentigo, photoaging) and DNA alteration. UVA rays also penetrate the dermis and cause injuries.

A complete sunscreen must have two protection indexes, which are generally not the same. Thus, FPS or IP is classified as 2 (weak defense), 8 (medium), 15 (strong), 30 (very strong) and +50.

The PPD represents the following indices: 2 (weak), 4 (medium), 8 (strong) and 14 (very strong).

When used correctly, sunscreens reduce the likelihood and severity of sunburn by blocking ultraviolet (UV) rays. But not all barriers are the same, so their effects also differ depending on their composition and the type of skin for which they are intended. "It is very important that the product contains a combination of filters to protect against any radiation," says Consuelo Soler, scientific director of Laboratorios Vichy. “It is also not true that a high index does not tan the skin. It tans the same way, but it takes a little longer. It's worth the wait to take care of your health. "

SPF indicates how long it is safe to tan, compared to exposure without a sunscreen. For example, a person who is able to stay on the first day of exposure for 15 minutes without risk of burns, SP factor 8 will protect him from the sun without risk for 120 minutes (8 x 15).

“The higher the protection factor, the better. People have already lost their fear of high stakes. The idea of ​​tanning is no longer prevalent, it is more an idea to sunbathe safely.