Vitamin C and SPF are the two most effective things you can put on your face in the morning — and they work better together. Here's the correct order, how long to wait between layers, and the mistakes that cancel both out.

Where does SPF go in your routine, before or after moisturizer, primer, and makeup? Here is the dermatologist-approved order to layer sunscreen so your protection actually works, plus the timing mistakes that quietly cancel it out.