Several topical ingredients can meaningfully improve acne scars, but the right ones depend on what kind of scarring you’re dealing with. Indented (atrophic) scars need ingredients that rebuild collagen in thinned skin. Raised scars need ingredients that slow excess collagen production. And dark or red marks left behind after breakouts need ingredients that target pigment. Here’s what works, how each ingredient acts on your skin, and what to realistically expect.
Indented Scars vs. Raised Scars vs. Dark Marks
Most acne scars fall into one of three categories, and knowing which type you have narrows down which ingredients are worth your time. Atrophic scars are the most common: small depressions or pits where inflammation destroyed collagen beneath the surface. The skin there is thinner than surrounding tissue. Hypertrophic scars are the opposite, raised and firm, formed when the body overproduces collagen during healing. These are less common on the face but show up frequently on the chest and jawline.
Then there are post-inflammatory marks, which aren’t true scars at all. These are flat discolorations, either dark brown (from excess melanin) or pink and red (from lingering blood vessels). They fade on their own over months, but certain ingredients speed that timeline considerably.
Retinoids for Rebuilding Lost Collagen
Retinoids are the most studied topical ingredients for atrophic acne scars. They work by signaling skin cells to increase production of procollagen, the precursor your body uses to build new collagen fibers. Since atrophic scars form precisely because inflammation broke down the collagen beneath the skin’s surface, replacing that lost structure is the core repair mechanism.
A six-month trial published in the American Journal of Clinical Dermatology found that adapalene 0.3% combined with benzoyl peroxide 2.5% produced significant improvement in global scar grades. Tissue analysis showed increased markers for two types of collagen (procollagen-1 and collagen-3), confirming that the improvement wasn’t just surface-level smoothing but actual structural remodeling beneath the skin. Tretinoin, the prescription-strength retinoid, has also been shown to stimulate procollagen production in damaged skin.
If you’re starting with retinoids, expect a slow process. Collagen remodeling takes months, not weeks. Over-the-counter adapalene (0.1%) is available without a prescription and is a reasonable starting point. Tretinoin requires a prescription and comes in higher concentrations. Both can cause dryness and irritation initially, so starting with a low concentration a few nights per week helps your skin adjust.
Vitamin C for Collagen and Discoloration
Vitamin C (in its active form, L-ascorbic acid) plays a direct role in collagen production. Without it, your body can still produce collagen proteins, but they remain soluble and understructured, unable to form the stable, insoluble fibers that actually give skin its firmness. Research on cell cultures shows that the amount of stable collagen deposited into the skin’s structural matrix is directly proportional to the concentration of vitamin C available. In other words, it’s not optional for collagen repair; it’s a required building block.
Beyond collagen, vitamin C is an antioxidant that helps fade both dark and red post-inflammatory marks by interrupting melanin production and calming vascular inflammation. For acne scars specifically, a serum with 10 to 20 percent L-ascorbic acid at a low pH (around 3.5) penetrates most effectively. It oxidizes quickly once exposed to air and light, so look for products in opaque, airtight packaging.
Niacinamide for Dark Marks
Niacinamide (vitamin B3) targets post-inflammatory hyperpigmentation through a mechanism that’s different from most brightening ingredients. Rather than blocking melanin production at its source, niacinamide reduces the transfer of pigment granules from the cells that make them to the surrounding skin cells that display them. It also appears to interfere with the chemical signaling pathway between these two cell types, further reducing pigment output.
This makes niacinamide particularly useful for the brownish spots left after breakouts, especially in darker skin tones where hyperpigmentation tends to be more persistent. Concentrations of 4 to 5 percent are commonly used in studies. It’s well tolerated, rarely causes irritation, and layers easily with other active ingredients like retinoids and vitamin C.
Azelaic Acid for Pigmentation and Texture
Azelaic acid pulls double duty on acne scars. It inhibits tyrosinase, the enzyme responsible for melanin production, which makes it effective against dark post-acne marks. But it also has a more unusual property: it’s selectively toxic to abnormal, overactive pigment-producing cells while leaving normal ones alone. This targeted action makes it safer for long-term use than some other depigmenting agents.
Available over the counter at 10 percent and by prescription at 15 to 20 percent, azelaic acid also has mild anti-inflammatory and antibacterial effects, which help prevent new breakouts from creating new scars in the first place. It can cause mild stinging when you first start using it, but this usually fades within a couple of weeks.
Glycolic Acid for Surface Resurfacing
Glycolic acid, the smallest alpha hydroxy acid, works primarily on the skin’s outer layers. It accelerates the shedding of dead skin cells, which does two things for acne scars: it disperses trapped pigment more quickly (improving dark marks) and smooths uneven texture over shallow atrophic scars. One clinical study using a combination of 12 percent glycolic acid with a low-concentration retinoid found improvements in both scar appearance and post-inflammatory hyperpigmentation.
Glycolic acid won’t meaningfully fill deeper scars on its own, as it doesn’t penetrate deeply enough to trigger significant collagen remodeling. But as part of a routine that includes retinoids or vitamin C, it helps by clearing the surface layer so other active ingredients can penetrate more effectively. Start with concentrations between 5 and 10 percent for daily use. Higher concentrations (20 percent and above) are used in professional chemical peels.
Silicone for Raised Scars
If your acne scars are raised rather than indented, silicone gel or silicone sheets are the first-line topical treatment. Silicone works by forming a breathable barrier over the scar that increases hydration in the outer skin layer. This signals the fibroblasts (the cells responsible for producing collagen) to slow down, gradually reducing the excess collagen that makes the scar raised and firm.
Silicone also protects scarred skin from bacterial exposure, which matters because bacteria can trigger additional collagen overproduction in scar tissue. Over time, silicone helps restore the balance between collagen creation and collagen breakdown, resulting in a softer, flatter scar. Silicone sheets are worn directly over the scar for several hours a day, while gel formulations dry into an invisible film. Both require consistent use over at least two to three months to see results.
A Note on Hydroquinone
Hydroquinone has historically been one of the most effective ingredients for fading dark marks, but its availability has changed. The FDA no longer permits over-the-counter sale of hydroquinone in the U.S. due to reports of serious side effects, including rashes, facial swelling, and a form of permanent skin discoloration called ochronosis that occurs with prolonged use. It’s still available by prescription, where a provider can monitor usage and duration. If you see hydroquinone in an over-the-counter product, it’s being sold illegally.
Why Sunscreen Matters for Every Scar Type
UV exposure actively works against every ingredient on this list. Sunlight triggers pro-inflammatory and pro-fibrotic responses in healing skin, which means it can worsen both raised scars and indented scars by disrupting the remodeling process. It also directly stimulates melanin production, darkening post-inflammatory marks that you’re trying to fade. Any scar treatment routine without daily broad-spectrum sunscreen (SPF 30 or higher) is undermining its own results. This is especially true for retinoids and glycolic acid, which make your skin more sensitive to UV damage.
Combining Ingredients Effectively
No single ingredient addresses every type of acne scarring. A practical approach for most people with a mix of indented scars and dark marks would pair a retinoid (for collagen rebuilding) with niacinamide or azelaic acid (for pigmentation), vitamin C in the morning (for antioxidant protection and additional collagen support), and consistent sunscreen. If your scars are primarily raised, swap the retinoid for silicone gel applied directly to the scar.
Introduce new actives one at a time, spacing them about two weeks apart so you can identify what causes irritation. Retinoids and glycolic acid can both thin the skin’s barrier initially, so using them on alternating nights rather than together reduces the risk of redness and peeling. Results from topical ingredients are gradual. Most people see noticeable changes in texture and pigmentation after 8 to 12 weeks of consistent use, with collagen remodeling continuing for six months or longer.