Here's Why You Should Never Mix Your SPF With Foundation Or Moisturizer

Sun protection is arguably the most important element of everyday skincare. And yet it also happens to be one of the most overlooked and forgotten steps. The sun is one of the top causes of premature skin aging, which appears as wrinkles, sagging, and age spots on the skin (via the Skin Cancer Foundation). More importantly, sun exposure increases your risk of skin cancer and skin precancer. Nevertheless, wearing daily sunscreen with an SPF (sun protection factor) level of 15+ will lower your risk of squamous cell carcinoma by approximately 40%. It will also cut your chance of developing melanoma in half. Regardless of your skin's complexion and whether you burn easily or not, the daily use of SPF is vital for everyone. Keck Medicine of USC explains that you generally need to wear SPF even if you're staying inside all day as glass windows don't always block out the sun's UVA rays, which leads to premature skin aging.

One of the reasons why people tend to leave SPF out of their skincare routine is because they don't know how to incorporate it properly. Using SPF in conjunction with foundation or moisturizer can be confusing, which leads people to simply mix their sunscreen in with their other skin products. However, experts warn against combining your sun protection with anything else. SPF should always be applied to your skin on its own.

Why you shouldn't mix SPF with other products

The primary reason why you shouldn't mix SPF with products like foundation or moisturizer is that adding your sun protection to any other liquid or powder will dilute the SPF (via Sun Butter Oceans). Diluting your SPF lessens its power, which reduces the protection it gives your skin against the sun. So, even though you're still applying SPF, you're not likely to be getting adequate protection from the sun, both in terms of reducing your risk of skin cancer and reducing the signs of aging. Additionally, there may be ingredients in your foundation or moisturizer that interfere with your SPF and stop its efficacy altogether.

Lab Muffin Beauty Science explains that you can mix SPF and other products in very rare cases where the two products have already been blended by professionals, who have thusly studied the results. However, the majority of the time, it's best to apply SPF and other products separately, even if you are wearing them at the same time. The order in which you layer your skincare products will depend on what kind of SPF you're using. Chemical sunscreens need to be fully absorbed into the skin, so should be applied before moisturizer and foundation (via La Roche-Posay). But physical or mineral sunscreens should be applied after moisturizer and foundation as they need to sit on top of your skin to create a barrier. When it comes to reapplying throughout the day, you can then layer the sunscreen on top of your foundation.

Are all-in-one SPF products available?

When you want to both protect your skin and achieve cosmetic coverage, a great option is using an all-in-one product that gives you even coverage and a line of defense against the sun. To this end, tinted moisturizers are a popular choice. This hydrating cream with makeup pigments provides light coverage, and many brands contain SPF, too (via L'Oréal Paris). However, tinted moisturizers with SPF can be problematic because the amount of product that people generally use doesn't provide substantial sun protection (via Charlotte's Book). You'd need to use a full teaspoon amount of tinted moisturizer on your face to get the benefits of the SPF within, which is more than most people would apply.

Rather than relying on tinted moisturizer with SPF for sun protection, experts recommend tinted sunscreen as an all-in-one product. Cosmetic dermatologist Leslie Baumann, M.D., explains that tinted sunscreen contains iron oxides, which can block UV light and blue light — light that can also cause premature wrinkles and other signs of aging. Tinted sunscreen also contains pigment in a range of shades, which provides coverage to your skin while you reap the benefits of the product's protective qualities. Additionally, you can still apply tinted sunscreen on top of makeup if you'd like even more coverage. Whether you choose to use tinted or non-tinted sunscreen, daily SPF is crucial for your skin's long-term health. And blending it with other products reduces its capacity to protect your skin from skin cancer and premature aging.