Potent treatment formulated with 20% niacinamide and 1% zinc PCA to fade dark spots, control sebum, and brighten your complexion. How to Use: Apply 2-3 drops to cleansed and toned skin, gently patting it in until fully absorbed. Since this is a high-concentration serum, it is best to start using it 2-3 times a week to let your skin build tolerance before moving to daily use. Always follow up with a broad-spectrum sunscreen during the day to protect your skin.