It combines Niacinamide (Vitamin B3) with a hydrating moisturizer base, used as the final step of a skincare routine. Specific benefits depend on the individual product's full formula.

A moisturizer is generally used as the moisturizing step, while a serum is a lighter, leave-on treatment step applied earlier, before moisturizer. See the Niacinamide Serum collection for that format.

This depends on the specific formula and the other products in your routine. Check individual product directions, and introduce new products one at a time to see how your skin responds.

This varies by product. Check the specific product's own listing for its intended skin type and directions.