Read any article about skincare and you’ll no doubt see praise for products having hyaluronic acid in the formula. And that’s where the explanation ends.

So what exactly is the stuff? And why do you want it?

Hyaluronic acid may not be the newest or flashiest ingredient out there, but it’s tried and true and seriously good for your skin. First off, don’t let the word “acid” fool you. Hyaluronic acid isn’t harsh or skin-stripping at all. In fact, it’s the exact opposite—a powerful humectant (aka moisture-binding ingredient) that keeps skin plump and hydrated and, yes, young-looking.

“Hyaluronic acid is a naturally occurring polysaccharide (carbohydrate) in the human body,” explains Arielle Kauvar, M.D., director of New York Laser and Skin Care. “It’s present in large amounts in the spaces between skin cells, where it provides moisture, plumpness, firmness and suppleness to the skin. It’s also present in the eyes and in the joint spaces, where it acts as a lubricant and ‘shock absorber.’ ”Know how a baby’s skin always looks so deliciously dewy and pillowy? It’s because babies are born with a high level of hyaluronic acid, which keeps their skin plump and smooth. Unfortunately, your body produces less and less hyaluronic acid over time. “The amount of hyaluronic acid in skin diminishes with age, most significantly after age 40,” notes Dr. Kauvar.

READ MORE: The No. 1 Wrinkle-Preventing Ingredient

While you’re never going to get back that perfectly dewy baby-skin, it is possible to help restore the skin’s hyaluronic acid content and give grown-up skin a younger, fresher, more supple look. One way to do it is through hyaluronic acid fillers like Restylane or Juvederm, which a dermatologist or plastic surgeon injects directly into sunken or wrinkled areas to plump them up. “Structurally it’s the same molecule as the hyaluronic acid that naturally occurs in your body, but it’s produced in the laboratory,” says Dr. Kauvar. Common areas treated include the lines that run from the corners of your nose to the corners of your mouth (“nasolabial folds” as they’re called by dermatologists) or the hollows under your eyes (“tear troughs” in derm-speak).

The other way to help plump up skin is to use a serum or moisturizer that contains hyaluronic acid. While it won’t give you the dramatic, instantaneous results that a hyaluronic acid filler can, you will see benefits in the form of softer, smoother, more hydrated skin.

“Even though hyaluronic acid is a relatively large molecule, when you apply it topically it penetrates the dead cell layer (stratum corneum) and permeates the skin,” says Dr. Kauvar. “It increases hydration, improves elasticity and also reverses free radical damage, so it may have some benefit in protecting from UV damage.”Bonus? Hyaluronic acid is one ingredient that works across the board. “Every skin type, even oily, can benefit,” says New York City dermatologist Francesca Fusco, M.D. “Apply it alone if you have oily skin or under moisturizer if you have dry skin. It works well with acne medications, anti-aging products and sunscreens.”

Check out some effective hyaluronic acid products below and start babying (sorry, couldn’t resist) your skin:

Skinceuticals Hydrating B5 Gel
One of Dr. Kauvar and Dr. Fusco’s favorite hyaluronic acid products, this gel is great for counteracting Retin-A induced dryness. It’s super hydrating but light enough for oily skin types, too.

This drugstore staple is packed with ceramides and niacinamide in addition to hyaluronic acid. Perfect for sensitive skin, it’s fragrance-free and uber-gentle.

In Japan, one of these serums is sold every two seconds—and now it’s finally available stateside. With a combo of three different types of hyaluronic acid, it offers an intense dose of moisture yet still manages to feel lightweight.

Goldfaden MD Wake Up Call: Overnight Regenerative Facial
With retinol and avocado oil plus hyaluronic acid, this rich cream hydrates while helping tackle signs of aging. Great for dry skin types.