Everything you need to know about hyaluronic acid. The next time you’re out shopping for skincare, have a look at the ingredients list of serums, creams or masks that claim to hydrate and plump skin. Chances are, you’ll spot hyaluronic acid. As one of the most commonly used skincare ingredients, it is synonymous with hydration and often equated as a must-have ingredient for smooth and plump skin. But did you know that the human body has hyaluronic acid in our body? Naturally