A recent Consumer Reports study of 20 popular sunscreen brands found that only 2 meet SPF claimed after water emersion. Some brands tested had as much as 40% less then advertised.
Basics on sun protection – protect your body against both UVA (long wave-cause wrinkles, skin cancer) & UVB (short waves). UVA rays are less intense than UVB but penetrate deeper also going thru clouds and glass! UVA accounts for 95% of the rays that reach the earth.
SPF means Sun Protection Factor and refers ONLY to UVB ray blocking. An SPF 15 rating blocks 93% while a SPF 100 rating blocks 99%. Realize that NO sunscreen can block 100% of UV rays.
Sunscreens on the market can work in one of two manners: absorb the rays or scatter/reflect them before they can enter your skin. For a product to be labeled ‘broad spectrum‘ the FDA requires that a critical wavelength of at least 370 nanometers (nm) of rays be blocked.
POI (point of information -not a Hawaiian dish of taro root)
UVA 400 nm – 320 nm
UVB 320 nm – 290 nm
Important ALSO is your actions:
– use a ‘broad-spectrum’ water-resistant sun protector and reapply every 2 hours/when sweat/when come out of water- cover up wherever you do not apply sunscreen
– increase water intake -not alcohol or soda
– avoid sun 10am -2pm sun -find shade!
Have fun in the sun!