Acne scars have several effective laser treatments, and pico fractional and ablative CO2 laser are two of the most common modalities you’ll be offered. They work differently, have very different downtime, and produce different results. Here’s how to think about which is right for your case.
The short answer
- Pico fractional (PicoSure Focus Lens Array or PicoWay Resolve): less aggressive, less downtime, more sessions, lower risk, lower per-session cost. Best for moderate scarring.
- Ablative CO2 fractional: more aggressive, significant downtime, fewer sessions, higher risk, higher per-session cost. Best for severe scarring or skin that needs major resurfacing.
Most patients with mild to moderate acne scarring do better with pico fractional. Patients with severe boxcar or ice pick scarring may need CO2 for meaningful improvement.
How each treatment works
Pico fractional
Uses a special lens to split the picosecond laser beam into thousands of tiny columns of focused energy. The columns create micro-zones of disruption deep in the skin without damaging the surface. This triggers collagen production and tissue remodeling over months.
Key feature: the surface skin layer (epidermis) remains largely intact, so healing is quick and the risk of scarring is low.
Ablative CO2 fractional
Uses 10,600nm CO2 laser energy to vaporize (ablate) tiny columns of skin tissue, including the surface layer. Surrounding healthy skin then heals into the treated columns, replacing the damaged tissue.
Key feature: the surface skin is actively removed and regrown — more aggressive remodeling, but real downtime and risk.
Side-by-side comparison
| Pico fractional | CO2 fractional | |
|---|---|---|
| Aggressiveness | Moderate | High |
| Downtime per session | 1-3 days | 7-14 days |
| Sessions typical | 4-6 | 1-3 |
| Cost per session | $500-$1,200 | $1,500-$3,500+ |
| Total typical cost | $2,500-$6,000 | $2,500-$8,000 |
| Hyperpigmentation risk | Lower | Higher (especially darker skin) |
| Skin tone limits | Safer on Fitzpatrick IV-VI | Higher risk on Fitzpatrick IV-VI |
| Result timeline | 3-6 months for full results | 3-6 months for full results |
| Best for | Moderate scarring, rolling/boxcar | Severe scarring, deep boxcar/ice pick |
Which scar types each treats best
Rolling scars (shallow undulations)
Both treatments work. Pico fractional often handles rolling scars well with less risk. Most patients do better with pico for primarily rolling scars.
Boxcar scars (defined edges)
Pico fractional can soften boxcar scars over multiple sessions. CO2 is more dramatic, especially for deep boxcar scars. Choose based on scar depth and downtime tolerance.
Ice pick scars (narrow, deep)
Both lasers are limited here. Best approach is usually TCA CROSS (chemical chemo-resurfacing on individual scars) combined with one of these lasers for surrounding skin. Neither pico nor CO2 alone clears ice pick scars well.
Hypertrophic or keloid scars
Neither modality. Different treatment approach needed.
Post-inflammatory pigmentation (the dark or red marks)
Pico fractional is better. CO2 risks worsening pigmentation, especially on darker skin.
Downtime: what each actually looks like
Pico fractional downtime
Day 1: pink and slightly swollen, like a sunburn. Day 2: redness fading, mild “sandpaper” texture from micro-scabs. Day 3-5: scabs fall off, mild redness. Day 5-7: typical appearance returns.
Most patients can return to work next day with light makeup if desired.
CO2 fractional downtime
Day 1-2: significant swelling and oozing. Day 3-5: weeping serum, scabbing, peeling. Day 6-10: peeling complete, deep pink underneath. Day 10-14: pink fades to normal skin.
Most patients take 1-2 weeks off work or social commitments.
Risks and side effects compared
Pico fractional risks
- Hyperpigmentation (lower risk; usually temporary)
- Mild redness lasting longer than expected
- Acne flare-up (uncommon)
- Cold sore activation (if you have a herpes history)
CO2 fractional risks
- Hyperpigmentation (higher risk; especially Fitzpatrick IV-VI)
- Hypopigmentation (can be permanent)
- Prolonged redness (months)
- Infection (significant — open skin during healing)
- Scarring (uncommon but possible)
- Cold sore activation
For darker skin tones
This is where the difference is dramatic. CO2 fractional carries significant risk of pigmentation changes on Fitzpatrick IV-VI skin and is often not recommended without very careful patient selection. Pico fractional is much safer for darker skin and is the standard recommendation.
If you have darker skin and severe scarring that genuinely needs CO2, find a dermatologist with significant experience treating skin of color.
Combination approach
Some dermatologists combine modalities:
- Pico fractional for general resurfacing
- TCA CROSS for ice pick scars
- Subcision for tethered rolling scars
- Targeted CO2 for the deepest individual scars
This is often the best approach for severe mixed scarring rather than choosing one modality alone.
How to decide
- Get evaluated by a board-certified dermatologist who offers both modalities and will recommend honestly
- Discuss your downtime tolerance — can you take 2 weeks off?
- Discuss your skin type — Fitzpatrick IV-VI weights heavily toward pico
- Look at scar severity — mild to moderate favors pico; severe deep scarring may favor CO2
- Consider budget — both are expensive but at different time/per-session profiles
Bottom line
For most patients with moderate acne scarring, pico fractional is the better starting point. Less risk, less downtime, gradual but real improvement. CO2 is the more aggressive option for severe scarring where you’ve decided gradual won’t get you there.
Read our full pico for acne scars guide · Find providers offering pico fractional treatment.