Sunscreen Savvy- Choosing the Right SPF

Q&A logoQuestion:   How much SPF do I need to use  in the summer?  My favorite  foundation has  a 15SPF which I know is pretty low.  If I  also use a moisturizer with a 15SPF  will  that bring my protection to a 30 SPF?

Answer:  You’re righ,t a 15 SPF  is pretty low, but adding  another product with a 15 SPF will not give you a 30SPF.  Its not fair but the math on sunscren products  are not cumulative.  Your final SPF  will only be the  highest SPF you are using.  In this case, the final SPF  will still be 15.  If you use a moisturizer with a 30SPF  you final SPF will  be able  to face  the sun with a  very respectable 30 SPF.

Please  keep in mind that  the SPF numbers  are just an indication of how long you can stay in the sun without burning.   A 30 SPF means that you can stay in the sun  for 30 minutes without sundamage.  However these calculations were done in the laboratory and  made on the assumption that   at least  two teaspoons of sunblock  is  used on the face and  1-2 tablespoons are used on the body. I decided to put these  standards to the test and the results were both funny and troubling.  Clearly  few if anyone actually  use  the prescribed amount of sunblock  and   we often fail to reapply  during the day.  This means that   the SPF which we  have to  face the sun is much lower than  we think.  For that reason I recommend using at least an SF30 and in the summer aim for a 50 SPF.  During the day I dust on a mineral sunscreen powder like Brush On Block by Susan Posnick.  I can apply it over foundation  to  boost  sun protection.

One final thought.  If you have sensitive skin, rosacea, psoriasis you might find  chemical sunscreens too irritating.   Look for broad spectrum physical sunscreens that get their  sun block powers from minerals like  zinc oxide or titanium dioxide.

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