The Sunscreen Bible

August 19, 2016

Each June as I write about sunscreens, again,  I sometimes feel like that cartoon where the first frame shows a man talking to his dog and inside the bubble he is saying something like, “Go fetch the stick! Whatta good boy you are!” In the next frame it shows the dog listening and the caption reads:  “What your dog hears: blah, blah, blah, blah, blah:  I think I’ve convinced my friends and family to always cover up and then I see them on Facebook lying on the beach.

Protecting the skin from harmful ultraviolet rays is imperative for  preventing skin cancer and premature skin aging. 

Exposure of the skin to UV radiation can be reduced by sunscreens which fall into two  categories: physical and chemical.  Physical sunscreens provide protection via  minerals such as  zinc oxide and titanium dioxide. They do not penetrate into the skin but rather lie on top like a blanket,  reflecting the suns rays.   Physical sunscreens have significant limitations however.   They give a whitish appearance to the skin which  is more apparent the higher the SPF protection.  They can feel gritty and also be rubbed or worn off.  However, their protection begins upon application and they are perfect for babies.

Chemical sunscreens protect the skin by absorbing UV light.  There is about a 30 minute lag time before protection begins. Since chemical sunscreens penetrate the skin at least to some degree, they can be irritating.  New evidence suggests some chemical ingredients may even cause photosensitization in some skin, creating free radical damage, another primary cause of premature aging.  The biggest offenders are octocrylene, octyl methoxycinnamate (octinoxate), benzophenone-3 (oxybenzone) and benzophenone-4 (sulisobenzone).  Homosalate and  Mexoryl SX are considered relatively safe.  Some new sunscreens  have  added anti-oxidants to their formulas, attempting to  mitigate some of the potentially irritating effects of chemical sunscreen’s active ingredients.  Others are microencapsulating the active ingredients to safely protect skin prone to irritation or photosensitivity.

The most important things to know about sun exposure:  

There is no perfect sunscreen, there is no such thing as a sunblock, and thinking you don’t need sunscreen on a cloudy day is dead wrong. The safest approach to sun exposure is to avoid it between the hours of 9 am and 4 pm.  Daily apply a sunscreen which has both chemical and physical ingredients with an SPF of at least 30.  And when outside,  wear long pants, hats,  long sleeved shirts, gloves and sunglasses.

(First published 05/27/13)