What Is Hyaluronic Acid, and Why Is It in So Many Skin-Care Products?

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Hyaluronic acid. Although somewhat difficult to say (and even harder to spell), the skin-care ingredient commonly found in your favorite serums, sheet masks, and moisturizers is an important addition to your daily skin-care regimen. That's because hyaluronic acid (aka HA), which occurs naturally in the skin, binds to water molecules to plump your skin with hydration and, thus, help achieve a naturally dewy and glowy complexion.

• Shereene Idriss, MD, is a board-certified dermatologist in New York City who specializes in facial aesthetics and rejuvenation.
• Tsippora Shainhouse, MD, is a board-certified dermatologist in Beverly Hills and a clinical instructor at the University of Southern California.
• Min S. Ahn, MD, is a double-board-certified facial plastic surgeon in Boston.
• Nava Greenfield, MD, is a board-certified dermatologist in New York City.
• Karan Lal, MD, is a board-certified dermatologist and the director of cosmetic dermatology at Affiliated Dermatology in Scottsdale, Arizona.

And it's clear the word has gotten out about its benefits because an Allure's Readers' Choice Awards survey shows it's one of the most-demand ingredients of skin-care products. But hyaluronic acid does so much more than boost skin's moisture levels, which is why we asked skin-care experts to better explain the benefits of the ingredient. Ahead, we break down everything you need to know before you add it to your daily regimen.

• What is hyaluronic acid?
• What are the benefits of hyaluronic acid?
• Who should use hyaluronic acid?
• How to use hyaluronic acid, according to dermatologists
• What are hyaluronic acid fillers?
• Hyaluronic Acid: the TL;DR

Hyaluronic acid is a water-binding molecule (formally known as a type of glycosaminoglycan) found abundantly in the skin, says Nava Greenfield, MD, a New York City-based, board-certified dermatologist. "It works by attracting large amounts of water molecules and holding them in the skin," which is essential for maintaining skin hydration and plumpness. 

As we age, the hyaluronic acid content in our skin decreases, explains Scottsdale-based dermatologist Karan Lal, MD, which is one reason so many topical anti-aging products feature hyaluronic acid as a main ingredient. Like the hyaluronic acid our bodies produce naturally, lab-made skin-care products "attract and hold onto water molecules" on the skin's surface. This can help restore lost hydration and, in turn, very subtly smooth fine lines and wrinkles.

Hyaluronic acid, in addition to being emblazoned across hundreds of skin-care labels, has been the star of TikToks, YouTube tutorials, and even its own television commercial. The ingredient is everywhere for many reasons.

It hydrates the skin surface: As we age, we naturally lose collagen and hyaluronic acid, so the skin becomes dehydrated more easily. Explains Tsippora Shainhouse, MD, a board-certified dermatologist in Beverly Hills and a clinical instructor at the University of Southern California, hyaluronic acid products help lock in moisture from the environment and deeper dermis to fully hydrate skin. 

It helps protect your skin barrier: Dry skin can lead to a compromised skin barrier, causing flakiness, acne, and roughness (among other symptoms). Using a skin-care product with hyaluronic acid and other moisture-binding humectants helps ensure that your skin barrier functions properly.

It can plump up fine lines and wrinkles: Says Dr. Lal, “By increasing moisture in the skin, hyaluronic acid can temporarily reduce the appearance of fine lines and wrinkles.” 

It can help restore volume and structure: If you’re experiencing a loss of volume in your face, which is totally normal as you age, you can turn to hyaluronic acid. The ingredient is available as an injectable to help sculpt and bulk up areas of the face (but more on this later).

Hyaluronic acid is great for all skin types, says Dr. Shainhouse. In general, "[the ingredient] is nonirritating and does not trigger acne, rosacea, or allergic skin reactions," she says. There is, however, a small chance of adverse side effects.

Those with dry and/or more mature skin will benefit the most from using hyaluronic acid, says cosmetic chemist Sandra Bontempo. "As we age, our bodies produce less of it, so replacing hyaluronic acid topically will make the most impact on those of us who are middle-aged and older," she explains.

Hyaluronic acid has the word "acid" in its name, but there's no reason for sensitive skin types to tread lightly — it's safe for everyone. "There are no known side effects of utilizing hyaluronic acid, as again, it's produced in our bodies," says Bontempo. "Definitely talk to your doctor if you do experience side effects from a product that contains it — it could be due to another active or inactive ingredient."

There are many hyaluronic acid products on the market, but Dr. Lal says hyaluronic acid serum — with its lightweight and watery texture — is your best bet for getting the ingredient’s benefits. Ideally, these serums should be applied after cleansing when your skin is still damp. Dr. Lal also recommends face creams that contain hyaluronic acid. These formulas come in a range of textures including light gels and emollient butters that you can apply in the morning and at night. 

When choosing hyaluronic acid products, Dr. Lal also suggests looking for peptides and ceramides on their ingredients lists: “Peptides are the building blocks for the skin and they help hydrate the skin and retain moisture. Ceramides restore the skin barrier and, in addition to hyaluronic acid, can really boost the skin's moisturization.”

See how skin care has evolved within the last 100 years:

Hyaluronic acid also comes in the form of an injectable. "In dermal fillers, hyaluronic acid presents as a gel-like product that, once injected, attracts water to regenerate volume and re-create lost structure," explains Shereene Idriss, MD, a board-certified dermatologist in New York City. "This, in turn, helps reduce the overall sunken or sagging appearance of the face and softens the overall look of lines and wrinkles."

Currently, the only Food and Drug Administration (FDA)-approved hyaluronic acid fillers are Restylane, Restylane Silk, Restylane Lyft, Restylane Refyne, Restylane Defyne, Restylane Kysse, Belotero, Juvéderm, Juvéderm Voluma, Juvéderm Volbella, Juvéderm Ultra, and Juvéderm Vollure. Says Dr. Idriss, these fillers can be used for nasolabial folds, marionette lines (folds that run vertically from the corners of the mouth down to the chin), cheek augmentation, chin augmentation, undereyes, lips, and dorsal hands. 

Fillers aren't one-size-fits-all, so discussing your options with your dermatologist is essential to ensure you decide on the one that best suits your skin goals. "The different types of hyaluronic acid fillers are to a cosmetic dermatologist what the various types of paintbrushes are to a painter," explains Dr. Idriss. "They are made up of the same ingredient, but depending on the size of the formula’s molecules and how they are strung together, they vary in density, lift-ability, and longevity."

Her best example is comparing Voluma, which tends to be stiff in nature and can hold more weight, to Belotero, a finer, more pliable filler for superficial lines and folds.

Hyaluronic acid fillers aren't permanent. What's more, they're reversible. If you're not happy with the results, your dermatologist can insert the enzyme hyaluronidase to dissolve the filler within minutes. "The enzyme works quickly — the material starts to dissolve immediately and is completely done within 24 to 48 hours," Min S. Ahn, MD, a Boston-based board-certified facial plastic surgeon, previously told Allure. However, he warns, those with bee allergies should use caution — and talk with a dermatologist — before signing up for a hyaluronidase-based procedure, as the enzyme is highly prevalent in bee venom.

Hyaluronic acid fillers are suitable for most people except those who are pregnant. There isn't much data surrounding pregnancy and fillers, but dermatologists tend to avoid injecting those who are expecting for fear of the unknown. Also, skip these fillers if you have an active skin infection. First, treat the infection, and then proceed with your appointment after your dermatologist has cleared you.

If you're considering getting hyaluronic fillers, there are a few potential risks. "With any injectable treatment, bruising and swelling are the most common side effects," says Dr. Idriss. "The good news is that these shortcomings are also short-lived." Plus, you can reduce the likelihood of bruising by avoiding blood-thinning agents, such as aspirin, ibuprofen, and red wine, a week or so before treatment.

Dr. Idriss says a larger concern is unintentionally injecting HA filler into a blood vessel (known as vascular occlusion), which may result in tissue death, scabbing, and scarring. The good news is that this is rare, and the aforementioned hyaluronidase can help to dissolve the filler, as long as your provider acts quickly.

Hyaluronic acid is a substance produced by our bodies to hydrate skin. It is also created in labs for skin-care products that offer a plethora of benefits, such as strengthening the skin barrier and visibly reducing fine lines and wrinkles. Hyaluronic acid can also be found in dermal fillers that help smooth, sculpt, and add volume to the face. But injectables come with risks. It’s best to speak to your doctor and see if the injectable is right for you and your skin goals. 

More skin-care terms to know:

• The Skin-Care Glossary: A Comprehensive Guide to Everything You Need to Know
• Why Glycerin Is the Ultimate Moisturizing Ingredient in Skin-Care Products
• Cica Is the Latest K-Beauty Ingredient Taking Over Skin-Care Products

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