Fractionated CO₂ Laser: How it Works, Indications, and Results

The fractionated CO₂ laser is, today, the most versatile treatment for rejuvenation, scars, and skin texture — but "doing laser" without correct indication and phototype adjustment is the fastest way to post-inflammatory hyperpigmentation and suboptimal results. This article explains what fractionated CO₂ does, how the session is, how many sessions are needed, and what to expect from the post-treatment period.

How fractionated CO₂ acts on the skin

The CO₂ laser emits light at a wavelength of 10,600 nm, which is intensely absorbed by the water in the skin. In fractionated mode, instead of treating the entire surface, the beam is divided into micro-columns (MTZ — Microscopic Treatment Zones), leaving islands of intact skin between them. Result: real ablative depth with accelerated recovery due to healing originating from the preserved islands.

What fractionated CO₂ treats well

Indication	Average Sessions	Expected Result
Mild facial rejuvenation	1 to 2	Texture, luminosity, fine wrinkles
Acne scars (atrophic)	3 to 5	40–70% reduction in depth
Old surgical scar	2 to 4	Color, relief, and texture closer to surrounding skin
Sun spots / solar lentigines	1 to 2	Progressive lightening
Stretch marks (whitish)	3 to 6	Texture closer to healthy skin
Vulvovaginal atrophy (gynecology)	3	Mucosal trophic changes and lubrication

What it does NOT treat well (and what to combine with)

• Melasma — may worsen; prefer non-ablative lasers + depigmenting protocol.
• Moderate/severe skin laxity — CO₂ helps with texture, but does not replace lifting; can be combined with microfocused ultrasound (Ultraformer/Ulthera) and microneedling radiofrequency.
• Active hypertrophic scar/keloid — CO₂ alone may worsen; protocol combines corticosteroid + 5-FU + laser infiltration.

How the session is

1. Topical anesthesia 45–60 min before (cream).
2. Cleaning, degreasing the skin.
3. Laser shots per area — full face takes ~20–30 min.
4. Application of soothing mask and barrier (hyaluronic acid + protector).
5. Departure with a red face, intense "sunburn" sensation.

Pre- and post-procedure (essential summary)

Pre (2 to 4 weeks before)

• Suspend retinoid acids and exfoliants the week before
• Strict daily sun protection (SPF 50+)
• Antiviral prophylaxis (acyclovir/valacyclovir) if recurrent labial herpes
• For phototypes IV–VI: topical lightening agent (hydroquinone) 2–4 weeks before to reduce post-inflammatory hyperpigmentation

Post (first 10 days)

• Cold compresses in the first 24h
• Repairing moisturizer (panthenol, ceramides) several times a day
• Mineral sunscreen as soon as the barrier allows (3rd–4th day)
• Do not pick at scabs — they fall off on their own between the 5th and 10th day
• Avoid direct sun and intense exercise in the first week

Real risks (and how to avoid them)

• Post-inflammatory hyperpigmentation — higher risk in darker phototypes; prevented with prior lightening treatment and adjusted parameters.
• Herpes reactivation — prevented with oral antiviral.
• Bacterial infection — wound care and, in some cases, topical antibiotic.
• Scarring — low risk with correct parameters; greatly increases in patients recently off isotretinoin.

Fractionated CO₂ vs. other technologies

• Fractionated Erbium — faster recovery, less deep collagen stimulation.
• Microneedling radiofrequency — better for moderate skin laxity; less effect on superficial texture.
• Phenol peel — deeper effect on wrinkles; much longer recovery and restricted indication.
• Microneedling — useful for maintenance; much less efficient than CO₂ for acne scars.

Frequently asked questions

What is fractionated CO₂ laser?

It is an ablative laser that emits micro-beams of light onto the skin in a fractionated pattern (microcolumns), promoting controlled evaporation and deep collagen stimulation. The skin around the microcolumns remains intact, which accelerates recovery compared to fully ablative CO₂.

What is fractionated CO₂ used for?

Acne scars, surgical scars, spots (solar lentigines, freckles), fine peri-oral and periorbital wrinkles, mild laxity, uneven texture, enlarged pores, and stretch marks. In gynecology, it also treats vulvovaginal atrophy.

How many sessions are needed?

It depends on the objective: mild rejuvenation usually requires 1 to 2 sessions; moderate acne scars, 3 to 5; hypertrophic scar/keloid or stretch marks, 4 to 6. Average interval: 30 to 60 days.

How long does recovery take?

Intense redness and fine scabs last 5 to 10 days. Residual redness may persist for 2 to 4 weeks. In darker skin tones, post-inflammatory hyperpigmentation may appear and requires a prevention protocol.

Does it hurt? Does it require anesthesia?

Topical anesthetic is applied 45 to 60 minutes before. For extensive areas or deeper parameters, anesthetic block or light sedation may be combined. The procedure itself lasts 20 to 40 minutes.

Who CANNOT have fractionated CO₂?

Pregnant women, patients who have recently used isotretinoin (Roacutan) — generally wait 6 months, active labial herpes (requires antiviral prophylaxis), active skin infections, and history of hypertrophic scars/keloids without prior evaluation. Darker phototypes (V and VI) require parameter adjustment to avoid hyperpigmentation.