I stay in Malaysia, well known for its sunny wheather, "Hot! very hot!" are the words we used to shout and complaint about the good wheather. As we, girls, wanted to whiter (skin tone) and brighter skin, sun is our biggest enermy! Dont tell me about the skin cancer, pre-mature skin, ageing bla-bla, we usually seek for sun protecter just because we scare of getting darken skin due to donno what effects. heh! here are some facts you have to know(From The Times, New York)!
Everyone knows that an SPF rating of 60 provides double the protection of SPF 30 — or does it?
Studies over the years have shown that sunscreen with an SPF, or sun protection factor, of 30 blocks about 97 percent of ultraviolet rays. A rating of 15 means 93 percent of UV rays are blocked, and anything higher than 30 remains in the 97 or 98 percent range.
What many people do not realize is that the amount of sunscreen applied plays an enormous role. A study in The British Journal of Dermatology this year found that applying less than two ounces over the entire body at one time can leave people with an SPF rating far lower than what is on the bottle. Some studies have shown that people typically apply just 10 percent of the amount recommended.
It is also important to look for sunscreens that protect against UVA and UVB radiation. SPF ratings apply only to UVB rays, and some sunscreens provide no protection at all against UVA rays, which penetrate the skin more deeply. For broad protection, look for sunscreens with avobenzone, zinc oxide or titanium dioxide, all of which block UVA.
THE BOTTOM LINE
Above SPF 30, the increased protection is minimal.
So, dont invest your money for higher SPF anymore (higher SPF usually costs you more) but pay attention to the quantity and frequency you apply, and is recommended to apply the sunscreen 30 minutes before you go under the sun. And it is better for you to re-apply after hours.