The best sun protection is the one you wear every day.
Too many skin problems are the result of sun damage. Protection is the best prevention. It's important to consider both UVB and UVA rays. They have different wavelengths, meaning they penetrate the skin at different depths.
UVB
(B for burns) are responsible for sunburn. They only attack the surface of the skin during sun exposure. They represent 5% of UV radiation.
UVA
(A for age) penetrate deeper into the skin. They are responsible for collagen breakdown, age spots, premature aging… They penetrate through windows, clouds… that's why you need to protect yourself daily, even if you're not sunbathing. They represent 95% of UV rays.
UVA and UVB rays decrease your skin's immune response and increase inflammation.
WHAT IS THE SPF?
The SPF (sun protection factor), also known as IP (protection index) or FPS (sun protection factor), is a measure of a sunscreen's effectiveness in protecting the skin from UVB rays. The SPF ratings on your sunscreens only measure sun protection against UVB rays.
SPF does not measure sun protection against UVA rays. To be protected against UVA rays as well, you must ensure that your sunscreen offers broad-spectrum protection. This guarantees UVA protection that is at least one-third the same as UVB protection. If your packaging states UVA/UVB, broad-spectrum protection, or broad spectrum protection, this indicates that the cream offers dual protection at a level of one-third of the stated UVB protection. Otherwise, UVA protection is not guaranteed.
There is also another protection measure according to Asian legislation: the PA index. It is expressed as a "+" from 1 to 4. This index measures protection against UVA rays. A PA index of ++++ will ensure good protection against UVA rays.
PROTECTION INDICATORS
If your skin normally burns after 10 minutes of sun exposure, applying SPF 15 sunscreen will allow you to stay in the sun without burning for approximately 150 minutes (15 times longer). This is a rough estimate that depends on skin type (phototype), the intensity of sunlight, and the amount of sunscreen used. SPF is actually a measure of protection against UVB exposure and is not intended to help you determine the duration of exposure.
The SPF protection scales are not linear:
SPF15 blocks 93% of UVB rays
SPF30 blocks 97% of UVB rays
SPF50 blocks 98% of UVB rays
Thus, an SPF 30 sunscreen offers only 4% more protection than an SPF 15 sunscreen, and an SPF 50 only 1% more than an SPF 30. The index therefore mainly determines the protected exposure time.
THE RIGHT PROTECTION
For optimal protection, experts recommend using a sunscreen with a minimum SPF of 30, applying about half a teaspoon to the face. Most people don't apply enough sunscreen, using only a quarter or half the recommended amount, which reduces its effectiveness. Therefore, to ensure your sunscreen is effective, you should apply it generously and regularly, regardless of the SPF.