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Hyaluronic acid is a humectant, which means it attracts water into the skin and plumps it with hydration. “Think of the skin as an actual sponge,” says board-certified dermatologist Ava Shamban, M.D., founder of SKINFIVE, about the ingredient category. “When it is dry, it is thin, brittle, not pliable, rough in texture, dull, and sallow in color. Run it under water, and it is instantly plump, dense, and smooth. Even the color is brighter.” 

And in case you need a friendly reminder: Your lip skin is, well, skin. Humectants like HA help pull moisture from the air into the upper layer of that skin to keep the cells hydrated and plump, without any of the stinging or burning that often comes with traditional lip plumpers. 

Hyaluronic acid works so well, in fact, that it has become the workhorse ingredient for many hi-tech topical lip fillers, including the Ourself Lip Filler. Specifically, this formula features multi-weight hyaluronic acid and vitamin B3 derivatives to smooth the look of lip lines and provide instant volume. (I’ve personally tested it, and trust me: It works.)

If you choose to use a balm, just make sure it also has emollients and occlusives (like butters and oils) to keep all that water locked inside—here are our favorite options that provide just the right amount of volume. 

Yes, hyaluronic acid functions as a humectant that pulls water into your skin. But your skin also naturally stores the buzzy ingredient! In fact, 50% of the body’s total amount of hyaluronic acid resides in the skin1. However, like all good things, your natural reserve of HA diminishes2 over time. And when your body’s hyaluronic acid declines, you may notice physical signs of skin aging, like fine lines, wrinkles, and dry, dull skin. 

To restore those levels, many experts recommend opting for a hyaluronic acid supplement. Think about it: If you regularly apply a HA serum for dewy skin, why wouldn’t you want to double down for even more skin-quenching benefits? (That’s why you can find it in Hailey Bieber’s skin-loving Erewhon smoothie, famously tagged at $17.) Here’s a list of our favorite supplements, all vetted by a nutrition Ph.D. 

At the risk of sounding like a broken record: Hyaluronic acid pulls water from the surrounding environment into your skin. For that reason, the humectant is a hero for soft, fluffy hair. How so? Well, as HA pulls water into the hair shaft, the strands become vibrant and full of moisture. 

Plenty of leave-ins, shampoos, and stylers include the ingredient in their formulas already—but you can apply a proper HA serum to your locks for a targeted treatment. “HA lives in my shower for the face and hair,” says board-certified internal medicine physician and skin care expert Zion Ko Lamm, M.D., on Instagram. Feel free to massage it into the scalp as well; like the skin on your face, your scalp can always use some extra T.L.C.

Again, just make sure you seal in all that hydration with a moisturizing oil. You’ll also want to apply the HA on damp hair, so that the humectant has enough water to attract.