What Fractional Laser Does for Acne Scars

How Fractional Laser Treats Acne Scars

A fractional laser passes over the skin in a grid pattern, creating thousands of microscopic columns of injury while leaving the surrounding tissue between them completely untouched. That untouched tissue is what allows relatively fast healing compared with treating the entire surface at once, while the injured columns trigger the skin's own wound-healing response, laying down new collagen that gradually fills in and smooths shallow depressions from acne scarring.

Fractional laser is used on the face most often, since that is where acne scarring is most likely to bother people cosmetically, though the same technology can treat scarring on the chest and back. Skin tone is a real factor in planning treatment: more deeply pigmented skin carries a higher risk of the laser itself triggering new post-inflammatory pigment changes, particularly with ablative settings, which is part of why treatment parameters are adjusted by skin type rather than applied uniformly to everyone.

Ablative vs Non-Ablative: The Real Tradeoff

Fractional laser vs ablative laser resurfacing is really a spectrum rather than two fixed categories, and where a given treatment falls on it changes the tradeoff between speed and downtime. Ablative fractional lasers vaporize tissue within each treated column, producing more visible injury, more redness, and several days to over a week of downtime per session, but often achieving more visible improvement per treatment. Non-ablative fractional lasers heat tissue beneath the surface without vaporizing it, meaning less downtime — often just mild redness for a day or two — but typically requiring more sessions to reach a comparable result.

Full ablative resurfacing, sometimes done with a CO2 laser across the entire face rather than in a fractional grid pattern, sits at the more aggressive end of this spectrum still, with longer co2 laser resurfacing recovery and a stronger single-session effect; fractional versions of the same technology were developed specifically to reduce that downtime while keeping much of the benefit.

Which Scars Respond Best

A narrative review of atrophic acne scar treatment found fractional lasers, both ablative and non-ablative, among the better-supported options across the acne scar types typically treated, alongside chemical peels, microneedling, subcision, and fillers, though it also noted that combination approaches tend to outperform any single modality and that overall evidence quality remains limited 1Ref 1Boen M, Jacob C (2024).Atrophic Postacne Scar Treatment: Narrative Review.That ablative and non-ablative fractional lasers are among the better-supported atrophic acne scar treatments, that combination approaches outperform single modalities, and that overall evidence quality in this field is limited.. Rolling scars and shallow boxcar scars, both broad and relatively soft depressions, tend to respond better than the narrower pitted vs raised acne scars distinction might suggest at a glance, since laser resurfaces a wider area rather than treating a single point like a punch technique would.

Deep, narrow ice-pick scars are the exception: because the scar itself is a tight, deep tract rather than a broad shallow depression, resurfacing the surrounding skin has less to work with, and these scars typically need a targeted technique addressing the tract directly rather than a resurfacing approach.

How Many Sessions It Actually Takes

Most people need a series of sessions, commonly spaced around four to six weeks apart, rather than seeing full results from a single treatment, since new collagen forms gradually over the weeks following each session rather than immediately. Improvement tends to be incremental and continues to build for months after the last session in the series, as remodeling continues quietly in the background long after visible redness has settled.

Sun protection in the weeks around each session matters more than usual, since freshly treated skin is more vulnerable to new pigment changes from ultraviolet exposure while it heals. Redness typically settles within days for non-ablative treatments and can last longer, sometimes over a week, for ablative ones, and most practices recommend avoiding direct sun and using a mineral sunscreen throughout the healing window between sessions.

Fractional Laser vs Other Scar Treatments

Fractional laser sits alongside subcision, microneedling, chemical peels, and filler as one option in a broader acne scar treatment comparison, and different scars, and different people's tolerance for downtime, often call for different combinations rather than a single universal answer. Silicone sheets, by contrast, are aimed at raised, hypertrophic or keloid scars rather than the pitted depressions fractional laser targets, which is why the two show up in very different scar conversations despite both being scar treatments.

For scars with a tethered, sloping edge, some practices combine fractional laser with subcision, releasing the fibrous band under the scar first and resurfacing afterward, on the reasoning that the two techniques address different structural aspects of the same depression rather than competing approaches.

Getting Acne Under Control Before Starting

Laser resurfacing works on existing scar tissue, but it does nothing to stop new scars from forming if acne is still actively flaring, which is why controlling active breakouts generally comes first. The AAD's acne guideline recommends topical retinoids and benzoyl peroxide, often as a fixed-dose combination, as an effective first-line approach for reducing ongoing inflammation 2Ref 2Reynolds RV, Yeung H, Cheng CE, et al. (2024).Guidelines of care for the management of acne vulgaris.That topical retinoids and benzoyl peroxide are strongly recommended first-line acne treatments, supporting the claim that controlling active inflammation should precede scar-focused laser treatment., and a review of that specific combination found it worked faster and more consistently than either ingredient alone 4Ref 4McKeage K, Keating GM (2011).Adapalene 0.1%/benzoyl peroxide 2.5% gel: a review of its use in the treatment of acne vulgaris in patients aged ≥ 12 years.That fixed-dose adapalene/benzoyl peroxide gel works faster and more consistently than either component alone, supporting the point that combination topical therapy reduces active inflammation before scar-focused treatment. — both relevant here because less active inflammation means fewer new scars competing with the ones already being treated.

This does not mean scarring has to wait for perfectly clear skin indefinitely; it means the acne is reasonably stable, with new inflammatory lesions no longer appearing regularly, before investing in a series of resurfacing sessions whose result a fresh breakout could otherwise undercut.

Timing Around Isotretinoin

Isotretinoin's known effects on the skin, including how it affects wound healing broadly, are why many practices build in a waiting period after finishing a course before starting fractional laser or other resurfacing procedures 3Ref 3Costa CS, Bagatin E, Martimbianco ALC, et al. (2018).Oral isotretinoin for acne.That isotretinoin's adverse-effect profile includes changes to skin and its healing response, supporting the caution about waiting before laser resurfacing during or shortly after a course.. The exact length of that wait varies by practice and by how the course went, which makes it a direct question for the treating dermatologist rather than something to assume from a general timeline.