TL;DR: Fractional CO2 laser (10,600 nm) is the ablative gold standard for skin resurfacing. The laser vaporizes microscopic columns of skin, sparing surrounding tissue. These micro-injuries trigger maximal collagen renewal and tissue remodeling. First-line for atrophic acne scars, deep wrinkles, stria, and Glogau III–IV photoaging. Downtime 5–10 days; results mature over 3–6 months.
Mechanism
10,600 nm is strongly absorbed by water. Each pulse vaporizes water-bearing skin instantly, creating a Microscopic Thermal Zone (MTZ). "Fractional" means only a fraction of the skin is treated (5–50% density); untreated islands between MTZs accelerate healing.
Three simultaneous effects:
- Ablative — vaporizes epidermis and upper dermis
- Thermal — heating around MTZs triggers collagen contraction
- Wound-healing induction — fibroblast activation, long-term collagen + elastin
Indications
- Atrophic acne scars (rolling, boxcar) — primary
- Deep traumatic / surgical scars
- Stria distensae (early erythematous phase)
- Periorbital + perioral deep wrinkles
- Glogau III–IV photoaging
- Actinic keratosis combined with pigmentation
- Comprehensive skin resurfacing
Skin types
| Fitzpatrick | Suitability |
|---|---|
| I–II | Ideal — lowest PIH risk |
| III–IV | Acceptable with low dose + PIH prophylaxis |
| V | Limited — non-ablative alternatives preferred |
| VI | Not recommended |
Procedure
- Consultation: Glogau staging, photos, expectation
- Pre-care 2–4 weeks: hydroquinone + retinoid for PIH prophylaxis
- Anesthesia: topical + local infiltration as needed
- Treatment: 20–45 min
- Recovery: edema + exudate first 48 h; crust 5–10 days; pink 2–6 weeks
- Post-care: SPF50+, antiseptic ointment, gentle skin care
Downtime timeline
| Day | Status |
|---|---|
| 0–2 | Edema, exudate, redness |
| 3–5 | Crusting begins, mild itch |
| 5–7 | Crust falls, pink new skin |
| 7–14 | Pink fades |
| 14–30 | Skin tone normalizes |
| 30–90 | Collagen remodeling peaks |
| 90–180 | Maximum clinical result |
Side effects
Expected: edema 48–72 h, exudate 24 h, crusting, pink (erythema) 2–6 weeks. Less common: PIH (especially Type III–IV), transient acne flare, HSV reactivation (needs antiviral prophylaxis), itch. Rare: bacterial infection, permanent hypopigmentation, scarring (wrong parameters or post-care), ectropion (periocular over-treatment).
Contraindications
- Active HSV (without prophylaxis)
- Bacterial skin infection
- Isotretinoin within 6 months
- Uncontrolled diabetes
- Keloid tendency
- Pregnancy / breastfeeding
- Active vitiligo
- Recent sunburn / tan
- Fitzpatrick VI (relative)
Pre-care (PIH prevention)
- 6 weeks before: hydroquinone 4% at night
- 4 weeks before: retinoid (tretinoin 0.025–0.05%) at night
- 2 weeks before: strict SPF50+, sun avoidance
- 3 days before: stop aspirin / vitamin E
- 1 day before: if HSV history, acyclovir 400 mg t.i.d.
CO2 vs Erbium:YAG
| Feature | CO2 (10,600) | Erbium (2940) |
|---|---|---|
| Water absorption | Moderate-high | Very high |
| Thermal damage | Deeper | Shallower |
| Downtime | 5–10 days | 3–5 days |
| Collagen response | Very strong | Moderate |
| Indication | Deep scars, deep wrinkles | Superficial fine lines |
| PIH risk | Higher | Lower |
FAQ
One session enough? Single session has significant effect; 2–4 recommended for acne scars. Less downtime alternative? Non-ablative fractional (1540/1550 nm) or RF microneedle. Summer? No. Autumn–winter ideal. Anesthesia painful? Topical usually adequate; local infiltration for sensitive zones. On acne medication? Stop isotretinoin 6 months prior; doxycycline/topical retinoid 1 week.
Our approach
- Glogau staging + photo + AI analysis
- HSV antiviral prophylaxis if indicated
- Hydroquinone + retinoid pre-care
- CE/FDA device, physician operator
- Day 7 and 14 follow-up; 3-month outcome review
Conclusion
Fractional CO2 — at the right patient + right parameters + disciplined pre/post-care — delivers durable, dramatic results. Non-ablative alternatives are better choices when downtime is unacceptable.
Dr. Murat Toktamısoglu, MD, PhD — Ataşehir, Istanbul. WhatsApp: +90 533 356 2480. Last medical review: May 18, 2026.
