What Is Hyaluronic Acid, and What Does It Do For Your Skin?

Ever wonder what's really behind the trendy skin-care ingredients in your beauty products? That's how we feel about hyaluronic acid, which has become a huge buzzword in the skin-care world in the last few years. You've likely seen the ingredient listed on bottles in your medicine cabinet and on face creams, serums, and cleansers in the aisles of your favorite beauty retailer. But what does hyaluronic acid do for your skin and does it live up to the hype? Since it's enjoying a resurgence, we reached out to dermatologist Debra Jaliman, MD, and cosmetic chemist Stephen Alain Ko to find out just what hyaluronic acid is, its benefits for the skin, and how to use it. Keep reading for the scoop.

Hyaluronic acid is a humectant, meaning it draws moisture from its environment and retains it like a sponge. According to Harvard Health Publishing, it holds over 1,000 times its weight in water.

"Hyaluronic acid plays an important part in the health of our connective tissue, skin's elasticity, and wound healing," Dr. Jaliman tells POPSUGAR. "It's present in all tissues and fluids." In fact, fifty percent of the hyaluronic acid in our bodies is found in our skin.

Dr. Jaliman describes the ingredient as a clear, gooey substance that occurs naturally in our bodies. Applied topically, the polymer has the ability to hydrate and plump your skin. Hence why it's a hero ingredient in so many great serums.

You might have noticed the ingredient being advertised on the bottles of some of your favorite moisturizers. "It's super hydrating and has antiaging properties," Dr. Jaliman says. "It helps to seal in moisture and creates fullness and plumpness to the skin."

The Dermato-Endocrinology Journal reported that younger skin is naturally pliable and bouncy due to its high water content. As we age, however, our skin produces less hyaluronic acid. "[This ingredient] can help slow down the loss of water from the skin, increasing skin hydration and its appearance," Ko says.

According to the International Journal of Biological Macromolecules, hyaluronic acid "exhibits remarkable skin regenerating and collagen stimulating" effects, both when used topically and when injected into the skin (more on that later). The article also noted that the ingredient "showed promising efficacy in skin tightness and elasticity, face rejuvenation, improving aesthetic scores, reducing the wrinkle scars, longevity, and tear trough rejuvenation."

According to Dr. Jaliman, all skin types can benefit from hyaluronic acid, but since it's such a good humectant, those with dry skin will especially notice a difference. According to Ko, hyaluronic acid is a polymer, meaning it can come in different molecular weights. "Smaller molecular-weight hyaluronic acids can penetrate into the skin, whereas higher-weight hyaluronic acids can form a film on the skin, slowing evaporation," he says.

Ko says that just because the ingredient is trendy doesn't mean it's the best at hydrating skin. "Glycerin, for example, outperforms hyaluronic acid in many tests," he says.

You can find many different products with hyaluronic acid. Dr. Jaliman suggests pairing it with squalene (a hydrating lipid), ceramides (which are used to protect the outer barrier of the skin and lock in moisture), and glycerin (a humectant that works by drawing water from the air into the skin's outer layer).

Dr. Jaliman says that hyaluronic acid is safe to pair with any of your favorite skin-care essentials: "There aren't any ingredients I'm aware of that don't pair well with it." So, layer away.

Because the substance is already in our bodies, it's an ideal ingredient for fillers (it's used for fillers like Juvaderm, Belotero Balance, and Restylane Lyft). "Its gel-like texture, especially when linked together, can provide volume and lift," Ko says. "Our body also has enzymes that slowly break down hyaluronic acid over time, which means it works as a temporary but long-lasting filler." The more you know!