Hyaluronic acid, or HA, is widely used in skin care products. In fact, this is the main ingredient in about a dozen serums and creams currently on the market, and HA can be found as a co-ingredient in many more cosmetic products. The reason HA is added to so many skin care products is due to its humectant properties (it helps hydrate skin), and HA even occurs naturally in the skin. So what is the big deal?

The problem is that not all HA is created equal, and research suggests it may even have detrimental effects at low molecular weights. It also remains unclear if low molecular variants of HA have the same pro-inflammatory effect when applied to the skin.