What is SPF? Is it kinda additive?
SPF stands for sun protection factor. It is the number rating of a sunscreen. The higher the number, the more protection you have against UVB rays. Most sunscreens claim to protect against UVA, but the protection is very minimal. Also, most sunscreens claim to be waterproof - this is a false statement, and sunscreens always need to be reapplied after heavy sweating or swimming. There is no such thing as a waterproof sunscreen. Hope that helps.
SPF Sun protection factor. It's just a number scale that indicates how much longer you can stay in the sun without getting burned as opposed to wearing no sunscreen at all. For example, an SPF of 15 means you can (supposedly) stay in the sun 15 times longer than you normally can without burning, but that assumes that you don't lose the protection by swimming or sweating. Not sure what pharmaceutical companies add to sunscreen to increase the SPF though.
SPF in sunscreen? Basically the higher the number the more of the UV rays it blocks out. The lower the number, the more you chance of getting a sunburn. It's not an additive.
