As dermatologists, we often hear questions from patients about ingredients in beauty and skincare products. Recently, hyaluronic acid (HA) has been hitting the shelves in a variety of products, from serums and moisturizers to sheet masks, night creams, and lip products. So what is HA? What benefits does it offer? And what are the most effective ways of using this ingredient?
What is hyaluronic acid?
HA is a humectant — a substance that retains moisture — and it is capable of binding over one thousand times its weight in water. This substance is naturally found in many areas of the human body, including the skin, eyes, and synovial fluid of the joints. HA used in beauty and skincare products is primarily made by bacteria in a lab via a process called biofermentation.
As we age, the production of key substances in the skin, including hyaluronic acid (along with collagen and elastin) decreases. As a result, our skin loses volume, hydration, and plumpness.
Lotions, potions, and injectable HA
Many skincare products containing HA claim to increase hydration within the skin. But is this true? The answer requires a closer look at the type of HA in the product. HA comes in different molecular sizes. Larger HA molecules, despite being the best at binding water and offering hydration, cannot penetrate into the skin. When applied topically (to the skin), these molecules sit on top of the skin, offering hydration only at the very surface. Smaller HA molecules, which bind less water than larger HA molecules, can penetrate deeper into the skin (though only into the epidermis, the topmost layer of skin). For maximum surface hydration, look for a product that contains HA molecules in a variety of sizes.
HA is also used in derma