Apply 2-3 drops after cleansing & toning. Let the serum absorb fully into the skin before moving on to the next step of your routine.When to use: AM & PM. Everyday|||How To Use:-A nourishing, daily serum packed with pure Vitamin B3 (Niacinamide) and powerful antioxidant EUK-134. Together they reduce sebum, acne marks, erythema and inflammation, and also protect skin against UV-induced DNA damage.