Why did Paula use avobenzone instead of titanium dioxide or zinc oxide in Sheer Cream Lipstick?
Paula chose avobenzone because both titanium dioxide and zinc oxide are rather opaque mineral sunscreens and it is difficult to create aesthetically pleasing sheer colors with them. In order to achieve an SPF 15 rating, the percentages of titanium dioxide and/or zinc oxide required would have created a fuller coverage lipstick whose colors would be dulled by the matte finish these ingredients have. Will it affect the sunscreen if I apply lip gloss over Sheer Cream Lipstick SPF 15? Yes, it will, but how much the sunscreen will be affected is unknown. Applying lip gloss over Sheer Cream Lipstick will not cancel out the sunscreen, but it will dilute it, just as applying moisturizer over a facial sunscreen dilutes that. If you do not plan on spending much time outdoors and want a glossier finish while wearing this product, it is OK to apply a light layer of lip gloss. However, if you want sufficient sun protection for a long day (more than two hours) outdoors, it is best to skip the gloss