Effective Vitamin C serum & K-beauty [SEP] I'm always interested in trying new skincare products, brands, and innovations.  Mizon is a well regarded South Korean skincare brand.  Vitamin C serum loses efficacy when it is exposed to oxygen, Mizun uses Arbutin to lengthen the efficacy of the serum.<br /><br />Topical Vitamin C sometimes  irritates my skin but I had no sensitivity to this.  It did go on easily with no greasiness or tacky feel.  It does feel like it tightens my skin and gives it a more even, brighter tone.