How to measure SPF?

Filed Under Beauty | 

Most women knows what is SPF, which stands for Sun Protection Factor. But what is it really means and how is it measured?

The number indicates how long it takes before sunburn occurs. Some volunteers are needed to do the experiments where they are exposed to light spectrum which mimic the noontime sun.

Some volunteers will wear sunscreen while others don’t.  The amount of light that induces redness in sunscreen-protected skin, divided by the amount of light that induces redness in unprotected skin is the SPF.  

So, a sunscreen with an SPF of 15 will delay the onset of a sunburn in a person who would otherwise burn in 10 minutes to burn in 150 minutes. The SPF 15 sunscreen allows a person to stay out in the sun 15 times longer.

So, dab on your sunscreen before you go under the sun! Yes protect against skin aging, damage and cancer!

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