Does SPF in moisturizer or foundation provide enough protection?

SPF in moisturizer or foundation provides some protection but is generally inadequate as a standalone. Most people do not apply enough of these products to achieve the labeled SPF — you would need about 7 applications of a powder or half a teaspoon of foundation to reach SPF 30. Using a dedicated sunscreen underneath and considering SPF-containing products as supplementary layering is the more reliable approach.