I did a little digging on sunscreens/sunblocks. I found the article below,
here. Sunscreens vs. Sunblocks
While many people, including myself often mix the terminology of sunscreen and sunblock, there really is a technical difference between the two. A true sunscreen is a chemical agent that denatures the light, making the wavelengths incapable of causing damage. Sunblocks literally act as a physical wall to prevent sunlight from reaching the skin’s surface.
Many “sunscreens” will contain a mixture of these 2 properties. For individuals with known contact dermatitis allergies, eczema or sensitive skin issues, the true physical blockers will be the agents best tolerated by the skin. Remember to check the ingredient list as far as the vehicle, which is the base that contains the active ingredient, to make certain it, doesn’t contain any other agents to which you are known to have sensitivities.
The following is a list of what your sunscreen/sunblock MUST do in order to provide you adequate coverage:
Contain a minimum SPF of 15 for routine exposure, with a higher SPF, (preferably around 30) for more intensive sun exposure, such as the beach.
Have broad spectrum protection, meaning BOTH UVA and UVB protecting ingredients are present. If your label doesn´t say they´re there, odds are they aren´t.
Be PABA free for those with sensitive skin, eczema or known PABA allergies.
Don’t be fooled by the product stating it’s waterproof. You MUST reapply after water exposure or every 2 hours while outdoors. Some contain bases with more "stay power" than others in that they are less likely to sweat into your eyes during sports such as Cellex-C Sun Care SPF 30 or SkinCeuticals Sport UV Defense SPF 45.
