Chlorphenesin is an organic product with a split personality. On the one hand, it is prescription-strength muscle relaxant. On the other hand, in cosmetics, it’s acts as a preservative with anti-fungal and anti-bacterial properties. As a preservative, it stabilizes a product’s pH balance as well as thickness and texture. It also prevents the product from breaking down by killing microorganisms that could develop ‘funky’ smells or colors. Given its split personality, it’s not surprising that chlorphenesin can irritate sensitive or dry skin and the FDA cautions against pregnant women and small children using these products. Other countries have restricted it through concentration limits.