Microneedling for Atrophic Acne Scars: How It Works and What Depth to Use

The short version: atrophic acne scars are depressed scars left when the skin heals with too little collagen. Microneedling can gradually soften them by triggering collagen induction in the scar tissue. Finer 33G (0.20 mm) needles make cleaner channels than thicker 30G; scar work uses the deeper end of the range (roughly 1.5–2.0 mm) and is usually done under professional guidance. Results are gradual and take several sessions.

What atrophic acne scars are

Atrophic scars sit below the surrounding skin because the healing process didn't rebuild enough collagen. They're commonly grouped as icepick (narrow, deep), boxcar (wider, sharp edges), and rolling (shallow, wavy). The fibres beneath a scar can also be tethered down, which is part of why they look indented.

How microneedling helps

Microneedling makes controlled micro-channels that prompt the skin's repair response, which lays down new collagen over time. For atrophic scars, that gradual collagen induction can help fill and smooth the depression. It's not instant — it works across multiple sessions spaced weeks apart, and different scar types respond differently.

What depth to use for scars

Reaching scar tissue takes more depth than routine maintenance. As a general guide:

Deeper settings reach the dermis but carry more risk, so 1.5–2.0 mm work is usually done by a professional. If you're at home, start conservative and don't exceed what your skin tolerates. Never needle over active acne or infection.

Why needle quality matters

Finer 33G (0.20 mm) needles make a smaller, cleaner channel than thicker 30G (0.30 mm) needles, with less tearing at the same depth. For scar work especially, clean channels and a stable, vertical entry (a high-torque motor) matter. Use EO-sterilized, single-use cartridges only.

Realistic expectations

• Improvement is gradual — expect several sessions over months.
• Not every scar type responds equally; rolling and boxcar scars often respond better than deep icepick scars.
• Protect treated skin from the sun and skip strong actives right after a session.

An adjustable pen lets you set the right depth for the job. See the Dr. Pen M8S (33G, 0.25–2.5 mm) →  |  33G EO-sterilized cartridges →