Hyaluronic acid is a molecule your body naturally produces, and it’s used in skincare, joint treatments, eye drops, and oral supplements. It works primarily by attracting and holding onto water molecules, which makes it useful anywhere the body needs moisture, cushioning, or lubrication. Here’s what the evidence actually supports.
Skin Hydration and Moisture Retention
The most popular use of hyaluronic acid is in topical serums and creams designed to hydrate skin. It works by pulling water into the upper layers of your skin, reducing what dermatologists call transepidermal water loss, which is the slow evaporation of moisture through your skin’s surface throughout the day. In clinical testing, 12 weeks of using a hyaluronic acid serum significantly improved skin barrier integrity compared to baseline measurements.
A randomized controlled trial of 65 women with periocular wrinkles (the fine lines around your eyes) found significant improvement in both skin hydration and elasticity after 60 days of using a 0.1% sodium hyaluronate formula. Another study in 20 women with moderate facial aging showed measurable improvements in hydration, moisture, elasticity, and skin tone after two months of regular use.
Most commercial serums contain between 0.1% and 0.3% hyaluronic acid and blend different molecular weights together. The larger molecules sit on the skin’s surface and form a moisture-trapping film, while smaller molecules penetrate deeper into the outer skin layers. This combination approach is why many products list multiple forms of hyaluronic acid on their ingredient labels.
Wrinkle Reduction
Hyaluronic acid can reduce the appearance of fine lines, though the effect takes time. A 12-week double-blinded, placebo-controlled study found that people taking oral hyaluronic acid saw significant improvements in wrinkle depth, water content in the outermost skin layer, and skin elasticity compared to the placebo group. These changes became statistically significant at 8 weeks and continued improving through 12 weeks.
The improvements come from two directions. Topically, hyaluronic acid plumps the skin by drawing water into it, which temporarily smooths fine lines. Taken orally, it appears to support skin hydration from the inside. In clinical trials, the standard oral dose is 120 mg per day, with supplements typically sold as 60 mg or 120 mg tablets.
Joint Pain and Osteoarthritis
Hyaluronic acid exists naturally in the fluid that lubricates your joints, and injectable forms are used to treat knee osteoarthritis. The evidence here is more mixed than the skincare data. Injections into the knee joint have a modest effect on early to moderate osteoarthritis, with pain relief peaking around 6 to 8 weeks after the injection. At that point, studies show significant improvements in pain during exercise and overall knee function.
The catch is that the effect doesn’t last. Most studies show the benefit fading by 18 weeks, and there’s very little evidence it’s still noticeable at six months. One study found pain improvement lasting up to a year, but this was an outlier. Pain at rest, as opposed to pain during movement, doesn’t seem to respond as well.
For people with mild to moderate knee osteoarthritis who want to delay more invasive treatments, these injections can offer a window of relief. They’re less useful for severe osteoarthritis or as a long-term solution on their own.
Dry Eye Treatment
Hyaluronic acid is a common active ingredient in artificial tears and lubricating eye drops. It thickens and stabilizes the thin layer of moisture that coats your eye’s surface by attracting surrounding water molecules with its chemical structure. Eye drops typically use concentrations between 0.1% and 0.4%.
Research shows that increasing the concentration from 0.1% to 0.3% leads to better outcomes, including less damage to the cells on the eye’s surface and improved tear film stability. Higher concentrations above 0.2% keep the tear film stable for longer, though they can occasionally cause temporary blurry vision. Across the published literature, hyaluronic acid eye drops improve tear stability, reduce evaporation, lower inflammation, and protect the cells on the surface of the eye.
Wound Healing
Your body uses hyaluronic acid during the natural wound repair process, where it helps regulate inflammation, guides new cells to the injury site, and supports the growth of new blood vessels. What’s interesting is that the molecule behaves differently depending on its size. Larger hyaluronic acid molecules calm inflammation and suppress excessive immune responses, while smaller fragments actually promote inflammation, which is necessary in the early stages of healing to clear out damaged tissue.
This dual role means hyaluronic acid is involved in multiple phases of wound repair, from the initial inflammatory response through tissue rebuilding. Some wound dressings and surgical products incorporate it for this reason.
How Different Forms Compare
Hyaluronic acid comes in three main forms you’ll encounter as a consumer, and each has a different risk and benefit profile.
- Topical (serums and creams): Considered safe with rare adverse reactions, including during pregnancy. These are the most accessible option and primarily target skin hydration and fine lines. Results take weeks of consistent use.
- Oral supplements: Also considered safe, with the standard studied dose at 120 mg daily. These support skin hydration and elasticity from within, with measurable results typically appearing after 8 weeks.
- Injectable: Used for joint pain and cosmetic fillers. While hyaluronic acid itself is safe, improper injection technique can lead to serious complications. This form should only be administered by a trained professional.
Products that combine hyaluronic acid with other active ingredients may carry additional risks from those other compounds. Pure hyaluronic acid, on its own, has an excellent safety profile across all three delivery methods.