The Ordinary DOUBLE VALUE PACK 2 X Niacinamide 10% + Zinc 1% 30ml Bottles. High-Strength Vitamin and Mineral Blemish Formula Niacinamide (Vitamin B3) is indicated to reduce the appearance of skin blemishes and congestion. A high 10% concentration of this vitamin is supported in the formula by zinc salt of pyrrolidone carboxylic acid to balance visible aspects of sebum activity. Contraindications: If topical Vitamin C is used as part of skincare, it should be applied at alternate times with this formula (ideally Vitamin C in the PM and this formula in the AM). Otherwise, Niacinamide can affect integrity of pure-form Vitamin C (L-Ascorbic Acid).