SPF 30, 50, 100: what does it really change?
SPF, or sun protection factor, is listed on every sunscreen bottle, but it's often misunderstood. SPF 30, 50, 100... These numbers may seem obvious, but they don't always reflect the true protection provided. Does SPF 100 really protect three times more than SPF 30? Not quite. Here's what these numbers really mean, and what they actually do for your skin.
What exactly is SPF?
SPF (Sun Protection Factor) indicates the level of protection against UVB rays, which are responsible for sunburn and, to a lesser extent, skin aging. For example, an SPF of 30 means that your skin will take 30 times longer to redden than it would without sunscreen, provided you apply a sufficient amount, which is often far from being the case.
What do the numbers mean?
- SPF 15 : blocks approximately 93% of UVB rays
- SPF 30 : blocks approximately 97% of UVB rays
- SPF 50 : blocks approximately 98% of UVB rays
- SPF 100 : blocks approximately 99% of UVB rays
Yes, the curve flattens. The protection gain becomes minimal beyond SPF 50. SPF 100 therefore does not mean “invincible in the sun,” but rather “a little extra boost… if you are very rigorous.”
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So, SPF 50 is better than 30?
Not necessarily. It all depends on your skin type, your exposure, and most importantly... your consistency. A well-applied SPF 30 cream every two hours often provides better protection than an SPF 50 cream applied in the morning... and forgotten.
SPF 30 is sufficient in most cases if you are strict.
SPF 50 is recommended for:
- very light or sensitive skin
- the children
- highly exposed areas (face, shoulders, etc.)
- extreme conditions (beach, mountain, tropics)
Tired of putting on sunscreen?
We understand. Rubbing it on every two hours isn't always practical, especially with children.
The good news? There is another effective and sustainable solution: UV-protective clothing.
At Loumio Paris, we offer tops, swimsuits, and bodysuits designed to block 98 to 99% of UVA and UVB rays. Comfortable, stylish, and reusable: no need to reapply sunscreen every two hours on the covered areas. And as a bonus: less plastic, fewer chemicals, and a planet that says thank you.
