Product Details Niacinamide (vitamin B3) is indicated to reduce the appearance of skin blemishes and congestion. The Ordinary offers a high 10% concentration of this vitamin that is supported in the formula by zinc salt of pyrrolidone carboxylic acid to balance visible aspects of sebum activity. Note: While Niacinamide and Zinc PCA reduce the look of blemishes and balance visible sebum activity neither is a treatment for acne. This formulation can be used alongside acne treatments if desired for added visible skin benefits. How To Use Apply to entire face morning and evening before heavier creams. 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).