A higher SPF does NOT mean longer protection from the sun!
A study from the Skin Cancer Foundation says that a high SPF gives people a false sense of security. You would think, an SPF 100 means I’m 100 percent blocked from the sun and I can stay out longer. But, that’s not the case.
SPF means Sun Protection Factor. SPF 30, for example, let’s in 1/30 of sun rays.
Here are the percentage breakdowns;
SPF 30 = 1/30 or 3%
SPF 50= 1/50 or 2%
SPF 100= 1/100 or 1%
So, to recap (and simplify) SPF 30 lets in 3 percent of sun rays, SPF 50 lets in 2 percent of sun rays, and SPF 100 lets in 1 percent of sun rays.
It’s a very small difference, even though the number on the actual bottle shows a bigger gap.
And, you must apply enough for the sunscreen to work in the first place. Dermatologists recommend using at least a palm-size amount to cover exposed parts of the body. Sunscreen takes 15 to 30 minutes to absorb. Sweat and water decrease the product’s effectiveness, meaning it must be reapplied often, no matter how high the SPF.
One more thing to consider. If the bottle says “broad-spectrum”, that means it’s protecting you from UVB rays (which cause sunburns) and UVA rays (which cause sun damage, like aging and wrinkles.) If the bottle does not have a broad-spectrum label, the product is only protecting you from sunburns.