SPF 20, 30, 50: What does this mean?

The terms IP, SPF, or FPS often cause confusion. Some users are overwhelmed by the multitude of sunscreens available on the market and often end up choosing one at random without paying much attention to the displayed indications. In reality, there is no difference between the acronyms IP, SPF, or FPS. These terms mean exactly the same thing: the FPS is the abbreviation for "Factor of Protection Solar", the SPF comes from "Sunburn Protection Factor" and the IP is the abbreviation for "Index of Protection". Thus, the number written on your tube of sunscreen has the same value, regardless of the brand or the country where you bought it: it is therefore a universal value.

Each of these indications represents the level of protection/efficiency of a sun care product against sunburn induced by UVB rays. Therefore, what matters is not the letters but rather the numbers that precede them. There are four levels of SPF:

• From 6 to 15 for a low protection ;

• From 15 to 25 for a medium protection ;

• From 30 to 50 for a high protection ;

• Of 50+ for a very high protection.

These protection factors represent the ratio between the exposure time needed to induce a sunburn with and without sunscreen. For instance, if a person starts to show redness after 5 minutes of exposure without sun protection, the application of a SPF 50 sunscreen allows to multiply this exposure time by 50 before getting a sunburn (5 minutes * 50 = 250 minutes). This means that, in theory, it would take 250 minutes, or 4 hours and 10 minutes, to get a sunburn with the sunscreen. However, these estimates have some drawbacks. Indeed, certain factors can weaken or even eliminate the action of the cream, such as poor application, an insufficient amount of sunscreen , sweating, swimming, rubbing with a towel or clothes, etc... They are as effective as in ideal conditions. That's why it's advisable to reapply it regularly to properly protect your skin.

It is important to remember that no protection completely stops the sun's rays. These sun protection factors can also indicate the amount of UVB that is blocked by your sunscreen product. Indeed, this is why we still tan, even when we apply sunscreen.

Thus, a product SPF 15 blocks approximately 95% of UV rays, a SPF 30 protects you against 96.7% of UVB rays, while an SPF 50 stops about 98.3% of UVB rays.

For instance, this means that a sunscreen product with an SPF 30 absorbs approximately 97% of UVB rays, while the remaining 3% penetrate the skin.

the higher the SPF, the more UV rays will be blocked by the product, and the less they will penetrate your skin thus, the more protected you are.

The choice of the sunscreen to apply depends on various criteria:

• The phototype: The lighter the skin, the higher the level of protection required. Dark and tanned complexions, less vulnerable to UV rays, can do without maximum protections when they are not subjected to prolonged and repeated sun exposure.

• The season : Even in winter, the application of sunscreen proves necessary since the UV rays penetrate the clouds : a cloud veil allows 90% and more of UV rays to pass through. However, it is possible to allow oneself to use medium protection.

• Times of the day: As the strength of the sun varies depending on the time of day, it is possible to alternate SPF levels throughout the day. In the morning and late evening, it is possible to use medium protection if you are outdoors. However, from 11 a.m. to about 3 p.m., favor sunscreens with a higher index, especially in the summer: this is when UVB rays are the strongest.

• The geographical area: People living in tropical environments, where the sun is bright all year round and for most of the day, need to protect themselves properly against the sun. In addition to a SPF 50 cream, it is preferable to reduce sun exposure.