Cosrx CosRx, The Niacinamide 15 Serum, 0.67 fl. oz. (20 ml)

This Niacinamide serum offers a strong, specialized formulation, which makes it highly effective for certain skin types but a poor choice for others. It was a huge success when I passed it on to my cousin with oily skin and provided excellent oil control, leading to less shine throughout the day and it appeared to have provided a strengthening protective skin barrier. For my own sensitive skin, the 1.5% concentration was too high and just after 3 days of use, I developed small whiteheads and irritation on my breakouts. I would highly recommend for non-sensitive oily skin, but I would strongly advise against sensitive or reactive skin types. If you have this skin type, then look for Niacinamide products with lower concentration