One of the questions I get asked most here on the blog and over on YouTube is:
“Do I really need separate sunscreen every day if my foundation has SPF in it?”
My answer is always the same: “YES! You really DO need separate sunscreen every day even if your foundation has SPF in it!” And here’s why:
People don’t put on enough foundation to get the full SPF rating that’s printed on the label. The average woman is only getting 1/4 to 1/3 of the sun protection that she thinks she’s getting by using foundation with sunscreen.
That’s because the FDA uses a mathematical formula for determining the SPF rating of any given product. So, to get the SPF on the label, the product must be applied in the same amount as in the FDA testing.
The formula used in the US is:
Which means, you need to apply 2 milligrams of foundation with sunscreen (or sunscreen) per square centimeter of skin in a uniform layer to achieve the SPF printed on the package. Obvious right?
I’m no mathematician so I consulted the google-sphere for a real world translation and the general consensus is that the formula translates into approximately 1/4 teaspoon of product for the average face.
The truth is that the average woman uses less than 1/3 of the needed amount to get the full protection advertised. For example, using one pump of foundation with an SPF 15 is really giving an SPF of ONLY 5.
Let me illustrate just how much foundation 1/4 teaspoon is:
That’s A LOT of foundation… I don’t know anyone who uses that much (and I can’t imagine how they’d look if they did)!
That’s why I recommend using a broad spectrum sunscreen of at least SPF 30 every day whether you’re wearing makeup or not.
Click here to find out which mineral sunscreens work best under makeup:
Best & Worst: Testing Mineral Sunscreens for Face
Click here for My Ultimate Sunscreen Guide: Beyond the Basics for answers to the most common sunscreen questions.
The bottom line is that sunscreen is a very effective tool, and our #1 line of defense against photo-aging, but it is an imperfect tool. The more you know about how it works, and how to use it correctly, the better equipped you’ll be to prevent the visible signs of aging as well as some skin cancers.