3 Reasons Not to Mix Sunscreen With Moisturizer

Dilutes SPF protection Mixing sunscreen with moisturizer reduces its concentration, so you get less protection than the label promises. There is no way to know how much less.

Breaks the tested formula Sunscreen is tested at a specific concentration and formula. Mixing it with anything disrupts that chemistry, making the product unreliable.

Better alternatives exist Use a moisturizer with SPF built in, as those are formulated and tested together. Or apply sunscreen first, let it dry, then moisturizer on top.