If you’re a skin care fanatic like I am, you know that sunscreen is essential for great skin.
But what you may not know is that higher numbers of SPF don’t mean that you’re getting maximal levels of protection.
How SPF Works
SPF 15 allows 1/15 UVB rays, or 6.6% through, meaning it blocks about 93.3% of UVB rays.
SPF 30 allows 1/30 UVB rays, or 3.3% through, meaning it blocks 96.6% of UVB rays.
SPF 100 allows 1/100 UVB rays, or 1.0% through, meaning it blocks 99.0% of UVB rays.
High SPF’s are not synonymous with better protection. For instance, notice above: A jump from SPF 15 to SPF 30 is more significant than a jump from SPF 30 to SPF 100, despite the drastic increase in the number.
SPF is Not UVA Protection
Higher UVB ratings do not necessarily mean higher UVA protection.
For instance, compounds like avobenzone and oxybenzone are excellent at screening UVA rays, but are sometimes available with UVB protection of just SPF 30.
UVA rays are longer-wavelength, and are more closely associated with developing signs of aging. They are also harder to guard against. Though UVB rays are more prevalent on a sunny day at the beach, UVA rays are everywhere — cloudy days, rainy days, coming through car and office and home windows, and basically creating daylight everyday. UVA rays are the reason why you need to wear sunscreen everyday, including in the winter.
So it is important to look for some of the following UVA blockers in your sunscreen:
High SPF does not translate to better UVA protection, which is necessary to prevent most of the visible signs of aging. When looking for an anti-aging sunscreen, be sure to look for stabilized UVA filters like homosalate, avobenzone, oxybenzone, octisalate, and octocrylene.