3rd Rock Sunblock® Sunscreen Lotion SPF 35 natural sunscreen is formulated exclusively from food-grade ingredients only. Consequently, it prevents skin damage caused by BOTH the sun and the toxic compounds. Like any traditional natural sunscreen lotion, 3rd Rock Sunblock® SPF 35 natural organic zinc oxide sunscreen offers unsurpassed UVA protection and provides pro-active skin benefits better than synthetic-based sunscreens. It does so by preventing DNA damage that causes cell mutation by blocking UVA (across almost the entire UVA spectrum) and UVB rays, rather than only blocking UVB (for which SPF is the sole indicator) and minimal UVA wavelengths like many standard sunscreens. Research studies have shown that cancer cells develop in acidic environments. Due to these studies and the need for providing a long term (3+ years) sun-stable product, 3rd Rock Essentials formulated 3rd Rock Sunblock® Sunscreen Lotion has an alkaline (NOT ACIDIC) pH.