So today, we'll look at that question. According to what I read, either one works but it depends on your personal preferences and a couple of other issues.
One thing that comes across is that products such as foundation and moisturizer containing sunscreen are notoriously unreliable in regard to its ability to protect. Since their SPF rating is lower, it may not provide the level of protection you really need. In addition, makeup is not always applied consistently on the face and it tends to wear off when you sweat or rub your face. It is recommended that once you clean your face, you apply a good layer of sunscreen before using your foundation and you should give the sunscreen a chance to dry.
The advantage of using a separate layer of foundation is that you can choose a higher SPF for protection. Furthermore, when you use a separate foundation and sunscreen, you can choose the exact type of sunscreen you prefer. So if you want a dryer finish, it's easier to get. I have a body lotion with sunscreen that I don't like because it is much greasier than I like. Think of the foundation or lotion as providing an extra layer of protection.
Although it is recommended one should use a product with an SPF of at least 30, one needs to apply a full ounce of sunscreen on your face to adequetly provide protection so you would need to apply at least one to one and a half tsps of foundation to your face to get the benefit of the sunscreen part. Furthermore, the sunscreen was rated with an SPF 30 before it is mixed with the foundation but once it is mixed with foundation, the SPF rating in no longer 30.
If you are not into wearing foundation but you want something that will even out the complexion and act as foundation, look at using a tinted sunscreen. Furthermore, if you select the proper sunscreen, it won't pill under the makeup.
Since it is important to reapply the sunscreen every two hours, one would ideally wash off all the makeup and start again by applying the sunscreen over clean skin and then reapply all of our makeup but we know most of us do not have time to do that. So it is recommended that one apply a loose powder or a mineral powder with SPF protection over everything regular to help protect the skin.
No matter which way you go, it is important to wear enough sunscreen to make it effective and to regularly reapply it every two to three hours. Let me know what you think, I'd love to hear. Have a great day.