The Basic Rules of Math Don't Apply to SPF Numbers.
SPF 100 does not offer twice the protection of SPF 50.
SPF 15 blocks approximately 93% of UVB rays,
SPF 30 blocks about 97% and SPF 50 blocks
about 98%. There is hardly a detectable
increase in protection over 50 SPF.
TIP: Regardless of claims, the SPF benefit is
only achieved when you use the right amount.
Use a one-ounce shot glass worth of sunscreen
to cover your body and a nickel-size amount to
protect your face.Reapply as needed.
With each sun exposure - whether or not sunburn forms - damaged
DNA triggers a cascade of detect/respond events. Repeated sun
exposure lessens the skin's ability to repair itself.
Studies have shown that repeated UV exposure:
+ Breaks down collagen
+ Impairs synthesis of new collagen
+ Causes DNA damage accumulation
After decades of similar detect/respond cycles,
discolorations, wrinkles and other signs of
photodamage develop. Protection, repair and
removal of sun-induced DNA damage is
key for defense.
Photoaging Occurs Over a Period of Years
When skin is hit by UVA and UVB rays, damaged cells send out
stress signals that begin a series of wounding responses.
Freckles, age spots, spider veins on
the face, rough and leathery skin, fine
loose and dry skin, a blotchy
complexion, actinic keratosis and skin
cancer can all be attributed to sun
exposure. DNA damage must be
repaired properly and quickly;
otherwise,the visible damage to the
supporting structure of the skin appears
as premature aging.