Procedure

Fractional CO2 Laser

An ablative laser that vaporizes thousands of microscopic columns of skin, leaving untouched skin between them to heal from. It is the most effective in-office treatment for indented acne scars, and the one with the most downtime and the highest pigment risk.
Dr. Schwarz, MD · Board-certified dermatologistLast reviewed September 8, 2026
16:9 hero for Fractional CO2 Laser. Never cropped: the tone strip and the corner logo depend on the full frame.

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This is the strongest tool we have for indented acne scars, and the one I discuss longest before booking. Done well it gives the biggest single change of anything on this list; done casually it gives a complication that outlasts the scars.

What I repeat in clinic: the downtime is real and not negotiable, about a week of oozing and crusting, then weeks to a couple of months of redness, so a wedding or a job start needs months of margin, and scars improve substantially rather than disappear.

On deeper skin tones I plan for dark marks rather than hope against them, and delayed pigment loss years later is the one thing nobody can fix, which is why conservative settings and an experienced provider are the price of admission.

— Dr. Schwarz, Board Certified Dermatologist

Key Facts

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Also calledAblative fractional laser, fractional carbon dioxide laser, CO2 resurfacing, fractional ablative resurfacing. Sold under device names including Fraxel re:pair, UltraPulse, CO2RE, SmartXide, and eCO2
Downtime5 to 10 days of visible healing, then weeks to a few months of lingering redness
Sessions1 to 3 for acne scars, spaced 6 to 12 weeks apart
Typical costAbout $1,000 to $3,000 per full-face session in the US, and more where sedation or an operating room is involved
Results timelineTexture keeps improving for 3 to 6 months, and collagen remodeling can continue for up to a year
PainSignificant. Strong numbing cream plus nerve blocks, injected anesthetic, or oral sedation is standard
Skin tone safetyThe highest pigment risk of the common scar treatments. Dark marks are common on deeper skin tones, and delayed loss of pigment is a rare but largely permanent risk on any skin
EvidenceStrong. It is the most studied and most effective single treatment for indented acne scars

What It Is

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A carbon dioxide laser produces infrared light at 10,600 nanometers, which water absorbs almost instantly. Skin is mostly water, so that energy vaporizes tissue instead of just heating it. That is what ablative means. Old full-field CO2 resurfacing removed the entire surface of the face, took weeks to heal, and scarred or bleached skin often. Fractional splits the beam into a grid of microscopic columns. Each column is vaporized to a chosen depth, and the untreated skin between columns holds the intact cells that heal everything around them. Density is how much of the surface gets treated, usually a few percent to a third; energy sets the depth. That change turned a treatment too dangerous for routine use into one that heals in about a week. It did not make it mild.

How It Works

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Two things happen in each column. The tissue is vaporized outright, and the column walls are left with a thin rim of heat-damaged tissue. Intact skin between the columns resurfaces the openings within a day or two, so healing takes days instead of weeks.

Underneath, the heat sets off a long wound-healing response. Old, disorganized scar collagen is broken down and replaced over months with collagen laid down in a more normal pattern. For indented scars that does two useful things at once: it removes the rigid tissue holding the surface down, and it builds new tissue that lifts the floor of the scar. Needling cannot do that, which is why CO2 results are better.

What makes it work makes it risky. The whole treated area is a real wound, so infection, pigment reacting to inflammation, and scarring from columns set too deep or too close are all possible. For scarring, density matters more than depth.

Water absorbs the energy, not pigment, but that does not spare deeper skin tones. The heat lands right beside pigment-producing cells and inflames them.

Skin is about two millimetres thick on the face. How deep a treatment reaches decides what it can change, and whether it treats all of the skin or scattered columns of it decides how long you take to heal.

How it works
Compare
Skin basics
EPIDERMISDERMISFAT0.05 mm — pigment0.5 mm — texture + pores1.0 mm — collagen1.5 mm — deep dermisPEELNEEDLINGNON-ABLATIVE LASERREACHES THE MID DERMIS

This works around one to one and a half millimetres down, in the middle of the dermis where collagen is made. That is the depth that changes scarring and firmness, and it is also why the downtime is longer and the result takes months to appear. The laser removes columns of skin outright: the white gaps here are tissue that is gone, and new skin grows in from the sides. The strongest of the four, and the longest to heal.

A peel or a scrub takes the skin off evenly from the surface down. Everything above the line goes and nothing below it is touched, which is why peels suit surface pigment and rough texture, and why the whole face flakes for a few days after.

Needles make hundreds of separate channels and leave the skin between them untouched. That untouched skin is what heals the rest, so recovery is quick — but a needle only injures the skin to start repair. It removes nothing.

The light passes through the surface and heats a column underneath it. The surface stays whole, so you leave red rather than raw — and it takes a course of sessions rather than one.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

What It Treats

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Wrinkles and Fine Lines
Wrinkles and Fine Lines
Strong evidence
The strongest result available from a device for fine lines, texture and sun damage, particularly around the mouth and eyes. One treatment usually does it, and the trade is a week or more of raw, red, peeling skin. The pigment risk is significantly higher on deeper skin tones, so settings are lowered, a test spot is done first, and the provider's experience with your skin matters.
Close-up of the cheek, nose and mouth of an adult with light skin, turned three-quarters away from the camera against a pale blue background. The surface of the cheek is uneven, dimpled with shallow depressions and small pits that catch the light. There are no active spots — the change here is in the texture of the skin rather than its color.
Acne Scarring
Strong evidence
The most effective single option for indented scarring, and the one with the most downtime — about a week of raw, swollen skin and months of strict sun avoidance afterwards. It does most for boxcar and rolling scars; icepick scars need something aimed at them separately. Settings are dialled back on deeper skin tones because of the pigment risk.
Close-up of a cheek with pink flushing and fine visible red blood vessels beside the nose
Rosacea
Moderate evidence
Used to reshape a nose that has thickened, by removing the excess tissue layer by layer. This is the answer for rhinophyma, since creams and tablets do not reverse it. It is a real procedure with real downtime of a couple of weeks, and results are strongly dependent on who does it.
Seborrheic Keratosis
Moderate evidence
An ablative laser can vaporise a growth precisely and is sometimes used when several need treating on the face. Like freezing, it destroys the tissue, so it is only for growths already confirmed as harmless. It is the most expensive of the options and it is not better than a curette for a single growth.

Not the Best For

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Stretch Marks
Stretch Marks
Limited evidence
An ablative laser that removes columns of skin rather than only heating them, so downtime is longer and the response can be larger. It is the highest-risk option on this page for post-inflammatory hyperpigmentation and for thickened scars on the chest, shoulders and upper back, which is why it is not a first choice on deeper skin tones.
Melasma
Melasma
Weak evidence
An ablative resurfacing laser with a real risk of making melasma worse, particularly on medium and deep skin tones. Any benefit tends to be short-lived and the rebound darkening can last a long time. If a clinic is offering aggressive resurfacing as the answer to melasma, that is a reason to get a second opinion.
Flat Brown and Red Marks After Spots
Doesn't work
The discoloration left behind after spots is pigment, not texture, and this laser does not treat it. Sunscreen, a pigment cream and time handle those marks. They are not a reason to have this treatment.

Pros and Cons

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Pros
  • The most effective option for scars More improvement than anything else.
  • Few sessions One to three, not six.
  • It treats everything at once Scars, texture, fine lines, sun damage, pores.
  • The result lasts Collagen rebuilt in a scar stays rebuilt.
  • Precise depth control Set for each person.
Cons
  • Real downtime Five to ten days of crusting, then weeks of redness.
  • The highest pigment risk here Dark marks are common on deeper skin tones.
  • It hurts Numbing cream is not enough. Nerve blocks or sedation are standard.
  • Expensive Usually $1,000 to $3,000 a session.
  • Infection and scarring are possible Uncommon, and both can leave marks.
  • Improvement is still partial Scars become less noticeable, not absent.

How to Prepare

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2 to 4 weeks before1 week before1 to 2 days before
Sun and pigment cream
2 to 4 weeks before
No sun, and do not arrive tanned. On deeper skin tones a pigment-blocking cream usually starts two to four weeks ahead.
Actives and smoking
1 week before
Stop retinoids, benzoyl peroxide and acids. Stop smoking if you can; it slows healing.
Antiviral tablets
1 to 2 days before
Antiviral tablets start a day or two before and continue for several days after, since an outbreak in healing skin can scar. Some providers add an antibiotic.
Plan ahead
Book the time off, arrange a driver if sedation is planned, buy plain petrolatum and a gentle cleanser, and plan a week at home.

What Happens

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ArrivingThe treatmentLeaving
Arriving
Skin is examined and photographed. The provider maps depth and density by area, treats scars harder, and checks the antiviral was started. Eye shields go in, metal ones under the lids if eyelids are treated. Thick numbing cream sits for 60 minutes, then injected anesthetic or nerve blocks, sometimes oral sedation for a full face. Your provider will ask about these things.
The treatment
The handpiece is passed or stamped over each zone. Expect rapid clicking, a burning smell, and a smoke evacuator running. Heat builds fast and feels hot rather than sharp. A full face takes 30 to 60 minutes, genuinely painful without proper anesthesia. The burning carries on for an hour or two.
Leaving
Skin is deep red, hot, swollen and weeping clear fluid, with a fine grid pattern visible. Ointment goes on thickly. You will not look presentable, so have a ride home.

Recovery

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Days 1 to 3Days 3 to 14Week 3 to Month 12
Days 1 to 3
Swelling peaks on the first or second morning and can partly close the eyes. Sleep propped up. Oozing dries into a fine crust. Gentle soaks and constant ointment. The hardest stretch.
Days 3 to 14
The skin turns bronze or grid-patterned brown, then flakes and sheets off, showing bright pink skin. Never pull or pick. Most are through the worst by day 7, and once the surface closes mineral makeup is allowed. Skin stays pink, dry and sensitive, and milia are common.
Week 3 to Month 12
Redness fades slowly, a month on light settings and three months or longer on aggressive ones. Normal, not a complication, and green-tinted makeup covers it. Texture and scarring keep improving, and the photograph that counts is taken at six months.

Aftercare

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7 to 10 days1 to 2 weeks4 weeks
Makeup
7 to 10 days
None until the surface closes, usually 7 to 10 days, then mineral makeup.
Exercise
1 to 2 weeks
Sweat and heat worsen swelling and irritate open skin.
Sun
4 weeks
Strict avoidance for at least 4 weeks, then SPF 30 or higher daily for months. Sun on healing skin is the biggest cause of dark marks.
Actives
No retinoids, acids or vitamin C until cleared, usually 3 to 4 weeks. Moisturizer and sunscreen only.
Ointment
Keep the skin covered in plain petrolatum for the first week; never let it dry out and crack. Avoid antibiotic ointments, which commonly cause allergic rashes on raw skin.
Cleansing
Gentle rinses or soaks several times a day, exactly as instructed. No scrubbing, washcloths or exfoliating.
Picking
None. Crusts come away on their own, and pulling them off is how this treatment leaves a scar.

Risks

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Everyone gets swelling, oozing, crusting, sloughing and weeks of redness. That is the treatment, not a complication. What follows sits beyond it, and these risks are more serious than with other resurfacing.

Dark patches
Flat brown marks appearing 2 to 6 weeks afterward. The most common complication, and on deeper skin tones common enough to plan for. It fades over months, faster when treated early.
Redness that will not settle
Redness that is worsening, or still intense after three months, needs review.
Pale or white patches
Pigment loss appearing months to years later, usually after aggressive or repeated treatment. Uncommon, largely permanent, and one reason settings stay conservative.
An acne or milia flare
Common in the weeks after, from ointment and healing skin. Treatable; report it rather than picking.
Itching that is severe
Some itch is normal. Intense itch with a rash can be an allergy to something on the skin, often an antibiotic ointment.

In Deeper Skin Tones

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Skin tone changes this decision more than any other. Fractional CO2 can be done on deeper skin tones, specialists do it routinely, and the pigment risk is high enough that it should never be booked casually.

The laser targets water, not pigment, but the heat lands millimeters from pigment-producing cells, and those cells answer inflammation by making more pigment. That gives post-inflammatory hyperpigmentation, flat brown patches over the treated area, usually two to six weeks afterward. On deeper skin tones it is common, not rare. It fades over months, faster with a pigment cream and strict sun avoidance, but expect a stretch where your skin looks worse than before.

The risk that cannot be undone is delayed hypopigmentation, patches where pigment is permanently lost. It appears late, sometimes six months to several years afterward, with no reliable treatment. It is uncommon, and it tracks with aggressive settings, high density, repeated passes and repeated treatments. That is why a careful provider uses lower density on deeper skin tones, spaces sessions further apart, and does two moderate sessions instead of one heavy one.

What good practice looks like: a test patch in a hidden area, a pigment-blocking cream for two to four weeks before and restarted after healing, lower density, ten to twelve weeks between sessions, and no sun for at least a month. Ask how many people with your skin tone the provider has treated on this device, and how many developed dark marks. Someone experienced will give you a number and a plan. Someone who says skin tone is not a concern has told you enough.

Plenty of people with deeper skin tones and acne scarring get a better trade from microneedling or radiofrequency microneedling: less improvement per session, far less chance of a pigment problem that outlasts the scars.

If You Stop

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There is little to stop. This is not a maintenance treatment, and the improvement does not reverse. Collagen rebuilt into a scar stays there, and people treated years ago still have what they gained.

What continues is ordinary aging and any acne that is still active. Untreated acne makes new scars, which is the usual reason someone thinks the result faded. Keeping acne controlled is part of the plan.

Stopping partway through a planned two or three sessions costs less than with needling, since each session delivers a real share of the result on its own.

Sun protection is the one thing that should not stop. Resurfaced skin pigments readily for months, and sun in that window turns a good outcome into a blotchy one.

Combining Treatments

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Same day
Acne treatment
Carries on, and active acne must be controlled before resurfacing.
Same day
Subcision
Often done first or at the same visit, to release tethered rolling scars.
Same day
TCA CROSS
Handles icepick scars, which respond poorly to resurfacing.
Pause 1 week
Retinoids and acids
Paused about a week before and three to four weeks after.
Order matters
Punch excision
Deep scars are cut out weeks earlier, then the face is resurfaced once healed.
Wait 2 weeks
Filler and neurotoxin
A couple of weeks before or well after, with filler later for leftover dips.
Wait 4 weeks
Peels, microneedling, waxing
Wait at least 4 weeks, longer if skin is still recovering.
Until healed
Other treatments
Nothing else until the skin has healed and the redness settled.
Wait 6 months
Isotretinoin
Most providers wait about 6 months after a course.

Insurance Coverage

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Insurance does not cover resurfacing for acne scars, which is classed as cosmetic. Resurfacing widespread precancerous sun damage is occasionally an exception, a different plan with a different goal.

Ask Your Doctor

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If you are pregnant or breastfeeding
Ask the doctor managing your pregnancy or breastfeeding first, including about the antiviral tablets and the anesthesia.
If you have a deeper skin tone
Ask how many people with your skin tone they have treated on this device, what settings they plan, whether they will do a test patch, and how they handle dark marks.
If you get cold sores
Antiviral tablets are standard for everyone and essential for you. An outbreak in healing skin can scar.
If you have taken isotretinoin
Say when, and whether you are on it now. Most providers wait about six months.
If you have had a keloid scar
Any thickened scar counts. It can rule out aggressive settings.
If you heal slowly
Diabetes and immune-suppressing medicines count. Healing is the whole treatment, and anything that slows it raises the risk of infection and scarring.
If you have had radiation to the area
Irradiated skin heals differently and may not be suitable.
If you smoke
Smoking meaningfully slows healing. Ask how long to stop beforehand.
If you take a blood thinner
Sun-sensitizing medicines too. Both change what happens during and after. Never stop a prescribed medicine on your own.
If you have an autoimmune disease
Connective tissue disease included. Some affect healing enough to change the decision.
If your scars are narrow and deep
Ask whether TCA CROSS, punch excision or subcision should come first. Resurfacing alone is not the answer.
If you cannot take a week off
That week away from people is part of the treatment. Ask about lighter settings across more sessions, or something else.

At-Home Versions

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Nothing sold for home use approaches this treatment, and the devices that claim to be similar are the ones worth avoiding.

At-home fractional laser devices
Okay alternative
A small number of low-energy handheld devices exist and are sold for fine lines and tone. Their energy is a tiny fraction of an office device by design, since a home user cannot judge depth or manage a burn. Some people see modest smoothing after months of use. None of them treat indented scars.
Plasma pens and fibroblast devices
Bad alternative
Frequently marketed as at-home resurfacing and mistaken for laser treatment. They burn the surface in dots and are a documented cause of scarring and permanent pigment change, including in salon settings, let alone at home.
Strong acids and peel kits bought online
Bad alternative
High-strength TCA and phenol solutions are sold as a shortcut to resurfacing. At those strengths they cause full-thickness burns and permanent scarring without trained application.
What actually helps at home
Good alternative
A nightly retinoid builds collagen slowly and genuinely, daily sunscreen protects the result, and a pigment cream handles the brown marks people often mistake for scars. This is also exactly what makes an office treatment work better and heal cleaner.

How It Compares

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Non-ablative fractional laser
The same
The closest alternative. It heats columns without vaporizing them, so downtime is two to three days rather than a week. Less improvement per session, so it takes three to five sessions, and the pigment risk is lower but not absent.
Erbium YAG resurfacing
The same
Ablative like CO2 but with less heat spreading sideways, so healing is a little faster and redness shorter. Slightly less collagen stimulation in exchange, and availability varies by practice.
RF microneedlingDiagram: how RF Microneedling works in the skin
RF microneedling
The same
Reaches depth through needles rather than light, so melanin does not absorb the energy. Less improvement for scars, considerably less downtime, and a much smaller pigment risk. Often the better trade on deeper skin tones.
MicroneedlingDiagram: how Microneedling works in the skin
Microneedling
Worse
Far cheaper, minimal downtime, safest across skin tones, and clearly less effective. Needs a course of three to six rather than one to three sessions.
Subcision and TCA CROSS
Different job
Each for a specific scar shape. They do jobs resurfacing does not, and are commonly done alongside it rather than instead.
A small clear glass bowl holding a shallow pool of pale amber liquid on a white background, with a white fan-shaped brush lying beside it, bristles resting against the bowl.Diagram: how Chemical Peel works in the skin
Chemical peel
Different job
For pigment and pores, none for indented scars at superficial depth. Not a substitute here.

Finding a Provider

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Ablative resurfacing is a physician-level procedure in most of the US. It should be done by a board-certified dermatologist or plastic surgeon, or by a physician assistant or nurse practitioner under direct supervision, and whoever sets the parameters should understand them.

Ask which device, what depth and density they plan, how many sessions, and how many people with your skin tone they have treated on that device. Ask to see their own before-and-after photographs in consistent lighting at six months, not six weeks. Ask their protocol for infection, dark marks and stubborn redness, and who you reach at nine on a Sunday night in the first week.

Red flags: no antiviral prophylaxis, no discussion of downtime, a promise that scars will be gone, photographs with mismatched lighting or makeup, treatment offered the same day as the consultation, no test patch on deeper skin tones, and a price far below everyone else.

Myths

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  • "CO2 laser removes acne scars completely." It does not. It is the most effective option there is, and across one to three sessions scarring becomes much harder to see. It does not become absent, and icepick scars need something else.
  • "Downtime is only a couple of days now that it is fractional." Fractional cut healing from weeks to about a week. It is still five to ten days of visibly healing skin, then weeks to months of redness.
  • "People with deeper skin tones cannot have this treatment." They can, and experienced providers do it routinely. Dark marks are genuinely more likely and need planning, and the rare permanent pigment loss is why settings stay conservative. Plenty of people are still better served by needling.
  • "Stronger settings always give a better result." Past a point, risk rises faster than benefit. Aggressive density is linked to scarring and permanent pigment loss, and two moderate sessions often beat one heavy one.
  • "If it is still red after a month, something went wrong." Redness for four to twelve weeks is expected, longer after aggressive settings. Redness that is worsening rather than fading is what to report.
  • "It works on brown marks left by acne." Those are flat pigment, not texture. They fade with time, sunscreen and a pigment cream, and chasing them with an ablative laser risks trading a temporary mark for a lasting one.

Questions Patients Ask

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How much downtime does fractional CO2 really need?

Five to ten days at home. Swelling and oozing days one to three, bronzing and sloughing days three to seven, and by day seven to ten the surface has closed and mineral makeup is usually allowed. Redness then fades over weeks to a few months.

Will it get rid of my acne scars?

It improves them substantially, more than any other single treatment, but it does not remove them. Rolling and boxcar scars respond best, icepick scars least, and mixed scarring usually needs subcision or TCA CROSS too.

Is it safe on deeper skin tones?

Experienced providers do it using lower density, longer intervals, and pigment creams before and after. Dark marks are common and fade over months. The rare risk of permanent pigment loss is why many people with deeper skin tones choose microneedling instead.

How many sessions will I need?

One to three, 6 to 12 weeks apart, judged six months after the last one.

Does it hurt?

Yes, without proper anesthesia. Numbing cream alone is not enough for a full face, so nerve blocks, injected anesthetic or oral sedation are standard, and burning continues for an hour or two afterward.

Can I have it before a wedding or a big event?

Only with months of margin. Skin looks worse before it looks better, and redness can last one to three months. Six months ahead is a reasonable minimum.

References

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