Yeah, I know. Why am I writing about sunscreen of all things? Well, I just had this bout of skin allergy. The dermatologist said it was probably because of the hot weather making me sweat and the moisture attracting all sorts of things. But anyway, she also looked at my skin and said that I had sensitive skin and that I should wear sunscreen everyday.
So, I saw this article on the web about choosing sunscreen and what all those acronyms mean:
Choosing the Right SPF
SPF stands for Sun Protection Factor. The higher the SPF number, the better protection against the sun's harmful UVB rays. The SPF number lets you know how much longer you can stay out of the sun without burning. For example, if it takes 15 minutes for a person to burn, an SPF 15 will allow them to stay out in the sun 15 times longer without burning.
The American Academy of Dermatology recommends wearing an SPF of 15 or higher for maximum protection. SPF is available in factors from 2-60. Does highest mean the best protection? Not necessarily. An SPF of 50 only provides 1-2% more protection than an SPF30.
UVA and UVB Protection
The label of the sunscreen will indicate the UVA or UVB protection.
UVA rays are responsible for the aging effect of the sun. However, overexposure to UVA rays can cause skin cancer.
UVB rays are responsible for sunburns and skin cancer.
Choose a product that has states "UVA/UVB" protection or has "broad spectrum" protectant.
Waterproof vs Water Resistant
If you are looking for a sunscreen to use while in the water, choose a sunscreen that is "waterproof" or "water resistant".
"Waterproof" sunscreen should provide protection in the water for 80 minutes, while "water resistant" provides only 40 minutes of protection.
Does highest mean the best protection? Not necessarily. An SPF of 50 only provides 1-2% more protection than an SPF30. 
