The short answer
0.25mm for serum absorption. 0.5–1.0mm for texture and fine lines. 1.0–1.5mm for scars. 1.5–2.5mm for stretch marks on the body. If you are unsure, start shorter — it is easy to step up next session once you have seen how your skin responds.
Needle length matters more than which pen you own. Someone improving serum absorption is not using the same depth as someone treating acne scarring, so it is worth taking a minute to land on the right number before your first session.
Needle depth by concern
| What you are treating | Depth | Notes |
|---|---|---|
| Serum absorption | 0.25mm | Best with hydrating serums; save retinol for non-treatment days |
| Uneven tone, texture | 0.5–1.0mm | The most common starting range |
| Hyperpigmentation | 0.25–1.0mm | Take it gently — deeper is not better here |
| Fine and deep lines | 0.5–1.5mm | Build up over sessions |
| Loose skin, sun damage | 0.5–1.5mm | |
| Scarring | 1.0–1.5mm | Scar tissue sits deep, so surface work will not reach it |
| Stretch marks | 1.5–2.5mm | Suited to thicker body skin rather than the face |
How often at each depth
The deeper you go, the longer the skin needs before the next session. The healing interval is where the result comes from, so spacing sessions out is doing more for you than it might feel like at the time.
| Depth | Frequency |
|---|---|
| 0.25mm | Every second day |
| 0.5mm | 1–3 times weekly (start with less) |
| 1.0mm | Once every 2 weeks |
| 1.5mm | Once every 3–4 weeks |
| 2.0–2.5mm | Every 6 weeks — best done with professional supervision |
Depth is not the same as pin count
These two are easy to mix up, so here is the difference in one line each. Depth is how far the needles travel, set on the device. Pin count is how many needles are in the cartridge, which changes coverage per pass rather than penetration.
- Fewer pins (11, 12, 16) — precision work on smaller areas, targeted scarring.
- More pins (24, 36, 42) — cover larger areas faster, spread the pressure more gently.
- Nano — surface only, no depth setting worth adjusting.
Our cartridge guide covers pin counts in full, and micro vs nano explains when to use each type.
Which device gives you the most control
Most Dr. Pen models use a continuous dial from 0 to 2.5mm, which means you set depth by eye. The Dr. Pen A20 uses nine fixed steps of 0.25mm instead, so you can repeat exactly the same setting next session. For scar work, where consistency between sessions is the whole point, that matters more than any other feature.
The Dr. Pen M8 covers the full 0 to 2.5mm range on a dial and is our lowest-priced device. For scalp and hair loss work the M8S is the one most people choose, because of its anti-backflow cartridge design.
Four things worth remembering
- Start shorter than you think. Build up across sessions once you know how your skin reacts.
- One cartridge, one session. They are sterile and single use — cleaning does not restore the edge, and blunted needles tear the skin rather than piercing it cleanly.
- Give irritated skin time. Active acne, open wounds and inflamed areas are best left to settle before you treat them.
- Body depths stay on the body. 2.5mm suits stretch marks on thicker skin; facial skin needs far less.
If you are choosing a device rather than a depth, our model comparison guide covers the full range with verified specifications. And if you would rather talk it through, send us a message — we are glad to help you land on the right depth for what you are treating.
Please speak with your doctor before purchasing any Dr. Pen product. This content is not intended to substitute for the advice of a qualified physician, pharmacist or other licensed healthcare professional.
