What is hyaluronic acid? A dermatologist breaks it down.

Retinol, niacinamide, vitamin C and hyaluronic acid: In recent years, these commonly-found ingredients have been name-dropped over and over again in the skincare community.

Hyaluronic acid, in particular, is best known for its purported ability to leave skin soft, supple and youthful. On TikTok, the hashtag “hyaluronic acid” has over 3 billion views to date. A brief scroll through some of the videos posted shows users raving about the benefits of this popular ingredient, with some offering up their favorite product recommendations, likely for a commission. Beyond social media, the ingredient is backed by science — the consistent use of hyaluronic acid serum has been proven to smooth and plump the skin, and ease the appearance of fine lines and wrinkles, according to a 2021 study.

So, to reap the benefits of this ingredient, USA TODAY spoke with a board-certified dermatologist to learn how to best incorporate hyaluronic acid into your everyday skincare routine.

What is hyaluronic acid?

Constant exposure to harmful elements, such as ultraviolet (UV) rays, makes your skin more susceptible to dryness and may exacerbate the loss of collagen, according to Harvard Health. Hyaluronic acid, also known as HA, works to combat these negative effects by restoring hydration, improving elasticity and encouraging collagen production in the skin. It’s considered a humectant, which is a natural substance that already exists in the human body, and it’s highly effective at locking in moisture, per Healthline.

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So, when used as an active ingredient in moisturizers and serums, hyaluronic acid becomes “a very versatile product that has a lot of really great uses for the skin,” says Dr. Karen Chinonso Kagha, MD, FAAD, who is a board-certified dermatologist in Beverly Hills, California.

What are the benefits of using hyaluronic acid?

Whether you’re looking to improve dry skin or restore hydration to your hair strands, using hyaluronic acid will elevate your day-to-day beauty routine. There are plenty of over-the-counter serums and creams containing hyaluronic acid that plump and restore radiance to your skin. There’s also a variety of shampoos, conditioners and leave-in products that promote hair and scalp health, according to Healthline.

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Hyaluronic acid is most effective when it comes to hydrating the top-most layer of the skin (or scalp), but cosmetic experts, including Kagha, also use hyaluronic acid in a different facet — as a volume-restoring dermal filler. “One of the ways that we age is by volume loss. So, a lot of the fillers that I do use to naturally replace that volume that we’ve lost [are] hyaluronic acid-based filler products,” she says. Hyaluronic acid injectables work by rejuvenating volume in the fat pads, Kagha says. These types of injectables create structure to the face, and can help diminish the appearance of fine lines and wrinkles, overall promoting a youthful appearance, according to the American Society for Dermatologic Surgery.

How often can you use products containing hyaluronic acid?

Kagha says it’s OK to use hyaluronic acid “multiple times a week.” Because hyaluronic acid is naturally-occurring, it’s a fairly tolerable ingredient that few are likely to have sensitivity to. Additionally, hyaluronic acid pairs well with other common skincare ingredients, such as vitamin C and niacinamide, she explains. As for retinol, Kagha typically recommends using retinol at night, and applying hyaluronic acid in the morning. However, if you’re experiencing increased dryness, there’s no problem with combining hyaluronic acid and retinol, she adds.

While there is little possibility of irritation when using hyaluronic acid on the skin, there are potential side effects linked with using hyaluronic acid as a dermal filler. When it’s injected into the skin, patients may experience swelling, bruising and tenderness at the site of injection, and occasional lumps, per WebMD. However, these side effects are more so linked to the injection procedure, rather than a negative reaction to hyaluronic acid itself, according to Healthline.

This article originally appeared on USA TODAY: What is hyaluronic acid? Benefits explained by a dermatologist