Hyaluronic acid does help with scars, though how much depends on the type of scar, the form of hyaluronic acid you use, and whether you’re applying it yourself or getting a professional treatment. Your body already produces hyaluronic acid naturally during wound healing, where it plays a direct role in controlling inflammation, guiding new tissue growth, and influencing how collagen forms. Adding more of it, either topically or through injections, can improve scar appearance, but the results vary significantly between an over-the-counter serum and a clinical procedure.
How Hyaluronic Acid Works in Healing Skin
When your skin is injured, hyaluronic acid production ramps up immediately. It binds to fibrinogen to kick-start clotting, then draws water into the wound site, creating a swollen, porous framework that allows immune cells and repair cells to migrate in. This is why fresh wounds puff up. That swelling isn’t just a side effect; it’s hyaluronic acid building a scaffold for healing.
As healing progresses, hyaluronic acid takes on a balancing act. Small fragments of it attract fibroblasts, the cells responsible for producing collagen and rebuilding the structural matrix of your skin. At the same time, larger chains of hyaluronic acid calm the inflammatory response by blocking excess immune cell activity. This dual role matters for scarring because too much inflammation or too much collagen production is what turns a healing wound into a raised, discolored scar. Different fragment sizes of hyaluronic acid actually stimulate different types of collagen, which can either promote or inhibit scar formation.
What Topical Serums Can and Cannot Do
Over-the-counter hyaluronic acid serums are widely available, but their ability to change scar tissue is limited by one key factor: penetration. High molecular weight hyaluronic acid (the type in many moisturizers) sits on the skin’s surface because the molecules are too large to pass through the outermost layer. Low molecular weight hyaluronic acid, in the range of 20 to 300 kilodaltons, can penetrate into the outer skin barrier, while anything above 1,000 kilodaltons largely stays put.
What topical serums do well is hydrate. In clinical testing, a hyaluronic acid serum increased skin hydration by 134% immediately after application, with a sustained 55% increase still measurable at six weeks. That same study showed improvements in smoothness (64%), plumping (60%), and fine lines (31%) over six weeks. For scars, this hydration effect softens the texture and reduces the contrast between scar tissue and surrounding skin. A well-hydrated scar looks flatter, less rough, and less noticeable.
But if you’re expecting a topical serum to remodel deep or raised scar tissue, it won’t get there. The benefits are primarily at the surface: better moisture, improved texture, and a subtler appearance. For newer, shallow scars or mild discoloration, that may be enough. For deeper acne scars, surgical scars, or keloids, you’ll need something that reaches further into the skin.
Microneedling With Hyaluronic Acid
One of the most studied professional approaches combines microneedling with hyaluronic acid applied during or immediately after the procedure. Microneedling creates tiny controlled punctures in the skin, which triggers a healing response and, critically, opens channels for topical products to penetrate far deeper than they normally would.
In a comparative clinical trial, microneedling alone improved acne scars by 32.45% over 17 weeks, while microneedling with hyaluronic acid improved them by 39.06%, a statistically significant difference. Beyond the numbers, more patients in the hyaluronic acid group achieved “good” or “very good” results, and none of the microneedling-only patients reached the “very good” category. Patients in the hyaluronic acid group also reported less oiliness and better overall skin texture as secondary benefits.
Injectable Hyaluronic Acid for Deeper Scars
For atrophic scars (the indented, pitted kind common after acne or chickenpox), injectable hyaluronic acid gel works as a filler. It physically lifts the depressed tissue to the level of surrounding skin. Clinical studies confirm that these injections are effective for moderate to severe atrophic acne scars, with improvement developing gradually over time rather than appearing all at once. Patients in these studies also reported gains in self-esteem and satisfaction with their skin’s appearance.
For depressed scars in delicate areas like around the eyes, hyaluronic acid fillers have been used after the scar tissue is first softened with steroid injections. In a retrospective study of this approach, hyaluronic acid was injected beneath the scar once the tissue was pliable enough, and results held during follow-up with no allergic reactions, skin damage, or significant recurrence. Only two cases showed minor re-indentation of less than one millimeter.
Raised Scars: Keloids and Hypertrophic Scars
Hyaluronic acid alone is not a treatment for keloids or hypertrophic scars. These raised, overgrown scars result from excessive collagen production, and since small fragments of hyaluronic acid actively stimulate fibroblast activity and collagen synthesis, applying it directly could theoretically feed the problem rather than fix it.
Where hyaluronic acid does play a role is in combination therapy. Steroid injections remain the standard for flattening and softening keloid tissue by suppressing fibroblast activity and reducing collagen output. Once a keloid has been softened enough, hyaluronic acid filler can be used to smooth out any depressions left behind by the steroid treatment, which sometimes causes tissue thinning. This two-step approach has shown durable results in case studies followed for over two years. But if you have active keloid or hypertrophic scarring, hyaluronic acid is a finishing tool, not the primary treatment.
Molecular Weight Matters
Not all hyaluronic acid products are equivalent, and the molecular weight of the hyaluronic acid determines what it does in your skin. High molecular weight hyaluronic acid is anti-inflammatory and anti-angiogenic, meaning it calms the tissue and doesn’t encourage new blood vessel growth. It’s better suited for surface hydration and for reducing redness in healing skin. Low molecular weight hyaluronic acid does the opposite: it’s pro-inflammatory and pro-angiogenic, driving the formation of new blood vessels and stimulating the fibroblasts that rebuild tissue. It also triggers the release of enzymes that break down and remodel old collagen.
For scar treatment, this distinction is practical. If you’re using hyaluronic acid on a fresh wound or new scar to keep inflammation in check and maintain moisture, a high molecular weight product makes sense. If the goal is deeper tissue remodeling of an older scar, particularly through a procedure like microneedling that allows penetration, low molecular weight hyaluronic acid has more biological activity where it counts. Many well-formulated serums now include a blend of both, but checking the label or product description for molecular weight information helps you pick the right one for your situation.
What to Realistically Expect
Topical hyaluronic acid serums improve scar appearance through hydration and surface smoothing within about six weeks of consistent use. The scar won’t disappear, but it will look and feel softer. Microneedling with hyaluronic acid shows measurable improvement over roughly four months, with the best results appearing after multiple sessions. Injectable fillers for depressed scars provide the most immediate visible change, though the effect develops fully over weeks as the tissue settles, and results from hyaluronic acid fillers are temporary, typically lasting six months to a year before the body absorbs the material.
For any scar treatment involving hyaluronic acid, earlier intervention generally produces better outcomes. Applying it during the active healing phase, when your skin’s own hyaluronic acid is already at work, supports the natural repair process. On older, fully matured scars, topical products have less to work with, and professional treatments become more relevant. Animal studies reinforce this: when hyaluronic acid film was placed in surgical wounds immediately, the tissue remained soft and pliable 60 days later, while untreated wounds were almost completely replaced by dense fibrous scar tissue in the same timeframe.