DHI Hair Transplant: The Implanter Pen, the Hairline, and Why It Is a Placement Method
Key takeaways
- DHI (direct hair implantation) is a variant of FUE that uses an implanter (Choi) pen to create the recipient site and place the follicle in a single motion, rather than making the sites first and filling them after.
- It is best understood as a placement method, not a different operation: the grafts are still harvested by FUE with a 0.7 to 1.2 mm punch, and donor dominance still governs the result.
- There is no society-level evidence that DHI improves graft survival over standard FUE; survival depends on handling and timing, not the tool, and sits commonly around 85 to 95%.
- DHI is often chosen for the hairline and dense frontal work because the pen gives fine control over angle and depth, but it typically covers fewer grafts per hour than manual FUE.
- A transplant redistributes existing donor hair and does not stop native loss, so medicine is often advised to protect the surrounding hair whichever placement method you choose.
By Felix Rowan | Medically reviewed by Dr Omar Haddad, MBBS, ABHRS
Published · 5 min read
A DHI (direct hair implantation) hair transplant is a variant of FUE in which the team uses an implanter, usually a Choi pen, to make the recipient site and place the follicle in a single motion, rather than making the sites first and filling them afterwards. It is best understood as a placement method, not a different operation: the grafts are still harvested one by one by FUE, and the same donor-dominance biology governs the result1.
When I was reading around before my own FUE, DHI was the option that confused me most, because every clinic seemed to sell it as a newer, better surgery. It took me a while, and a straight answer from a surgeon rather than a sales page, to understand that it is a way of putting the grafts in, not a way of growing more hair. This is the plain version I wish I had read. For the whole picture start with the hair transplant pillar, and to see where DHI sits among the methods read FUE versus FUT and what is FUE.
What is DHI?
DHI is direct hair implantation: an FUE technique in which the surgical team loads each follicular unit into a hollow implanter pen and, in one push, both creates the recipient site and sets the graft at a chosen depth and angle. In standard FUE the recipient sites are usually made first with a fine needle or blade, then the grafts are placed into those pre-made channels; DHI collapses those two steps into one2.
The important thing is what does not change. The harvesting is identical: follicular units, the natural clusters of 1 to 4 hairs, are removed one by one from the donor area at the back and sides with a punch of about 0.7 to 1.2 mm1. Transplanted follicles keep the behaviour of their donor site, the donor-dominance principle, so DHI treats the pattern of loss and not the cause, exactly as any transplant does. If the graft and density vocabulary is new to you, grafts and density sets out what a follicular unit actually is.
The implanter (Choi) pen
The Choi implanter is a pen-like tool with a hollow needle: a graft is loaded so the follicle sits inside the bore, the needle is pushed into the scalp at the intended angle and depth, and a plunger releases the graft as the needle withdraws. It lets the operator control the exit angle and depth of each graft directly, which is the main practical appeal2.
Because the pen sets the site and the graft together, teams often use several pens in rotation, one being loaded while another is placing. That control over angle matters because the hairline is created at a natural 15 to 20 degree angle, and consistent shallow angling is a large part of what makes a result look real rather than plugged2. The trade-off is speed: loading each graft into a pen is slower and more labour-intensive than placing pre-cut grafts into ready-made sites, so DHI typically covers fewer grafts per hour.
Why it suits the hairline
DHI is often chosen for the hairline and dense frontal work because the implanter pen gives fine, direct control over the angle, direction, and depth of each graft, which is exactly what a natural front row demands. The frontal hairline is the most scrutinised part of any transplant, so the precision that slows DHI down is worth most there3.
I felt this in my own consultation. My surgeon talked far more about the angle and irregularity of the front row than about the total graft count, and that is the judgement DHI is built to serve. It is worth saying the pen is not the only way to get a good hairline: skilled manual FUE placement achieves the same, and the tool does not design the hairline, the surgeon does. The design principles are the same either way, and I have set them out in hairline design.
Does DHI improve survival or density?
There is no society-level evidence that DHI improves graft survival over standard FUE; survival depends on how gently the grafts are handled and how quickly they are replaced, not on the instrument. Graft survival is commonly about 85 to 95% across methods, and figures of 95 to 98% are marketing rather than controlled data1.
Density is limited by biology, not by the pen. Transplants typically achieve about 30 follicular units per cm2, a range of roughly 25 to 45, which is about one third to one half of native non-balding density of 80 to 100 follicular units per cm22. The pen can help place grafts closely and at a steady angle, but your donor supply, commonly cited at about 6,000 to 8,000 grafts over a lifetime, is the real ceiling, not the tool. This is why I treat DHI as a placement method and nothing more, a point I keep coming back to in hair transplant myths and facts and hair transplant results.
DHI, scars, and shaving
DHI leaves the same tiny dot scars as any FUE, because it harvests grafts with the same 0.7 to 1.2 mm punch; the ISHRS is explicit that FUE is not scarless. The dots are usually hard to see once the hair grows, which is why FUE and DHI suit short styles better than the single linear scar of the strip method1.
The one place DHI can genuinely differ is shaving. Because the pen places grafts without pre-making channels, some clinics offer partial-shave or unshaven DHI for small hairline cases, though larger cases still usually need the donor shaved for clean harvesting. That is a case-size and clinic choice, not evidence of a different operation. For the full comparison of what each method leaves behind, see hair transplant scars and FUE versus FUT.
Do I still need medication with DHI?
Yes, often: a transplant redistributes DHT-resistant donor hair but does not stop your native hair thinning, so medicine is frequently advised to protect the surrounding hair whichever placement method you choose. The placement tool has no bearing on this; it is about the biology of the untransplanted, susceptible hair4.
Finasteride lowers DHT by about 70% and, over 5 years, kept regrowth or prevented further visible loss in about 90% of men; minoxidil prolongs the growth phase and needs at least 12 months to judge2. Skipping medicine is how people end up with a good transplant sitting in a receding native frame a few years on. I go into the reasoning in do I need medication after a hair transplant and weigh the options in hair transplant versus medication.
References
- Follicular Unit Excision (FUE), ISHRS. ↩
- Hair Transplantation, StatPearls / NCBI (NBK547740). ↩
- Hair transplants: What to expect, American Academy of Dermatology. ↩
- Hair transplant, NHS. ↩
Frequently asked questions
What is a DHI hair transplant?
DHI stands for direct hair implantation. It is a variant of FUE in which the surgical team uses an implanter, usually a Choi pen, to make the recipient site and set the follicle into the scalp in one motion. In standard FUE the sites are usually made first with a needle or blade and the grafts placed into them afterwards. The harvesting step is the same in both: follicular units are removed one by one from the donor area with a small punch.
Is DHI better than FUE?
DHI is a form of FUE, so the honest answer is that it is not a separate, superior operation. There is no society-level evidence that the implanter pen improves graft survival, which is commonly about 85 to 95% and depends on how carefully the grafts are handled and how quickly they go back in, not on the tool. DHI does give fine control over angle and depth, which is why many teams favour it for the hairline, but it usually places fewer grafts per hour.
Does DHI give better survival or more density?
Not by itself. Transplants typically achieve about 30 follicular units per cm2, roughly one third to one half of native density, whatever the placement method. Survival is skill-dependent and sits commonly around 85 to 95%. The pen can help pack grafts closely and at a consistent angle, but density is ultimately limited by your donor supply and by the blood supply of the recipient area, not by the instrument.
Is DHI shaveless or no-shave?
Sometimes, but that is a separate choice from DHI itself. Because the pen places grafts without pre-making the sites, some clinics offer it as a partial-shave or unshaven approach for small hairline cases. Larger cases still usually need the donor area shaved so units can be harvested cleanly. Whether you shave is about case size and clinic method, not about DHI being a different operation.
Is DHI more expensive?
It is often priced higher because it is slower and more labour-intensive per graft, but this is a clinic pricing decision rather than a reflection of a better result. In Phase 1 education terms, the sensible view is that you are paying for placement time and technique, not for a superior operation. Cost varies widely by country and clinic and should be judged alongside the surgeon and the plan, not the label.
Does DHI still leave scars?
Yes. Because DHI harvests grafts by FUE with a 0.7 to 1.2 mm punch, it leaves the same tiny dot scars across the donor area that any FUE leaves. The ISHRS is clear that FUE is not scarless. The dots are usually hard to see once the hair grows, which is why FUE and DHI suit shorter styles better than the single linear scar of the strip method.
Do I still need finasteride or minoxidil after DHI?
Often, yes. A transplant redistributes donor hair that resists DHT, but it does not stop your native, susceptible hair from thinning. Medicine such as finasteride, which lowers DHT by about 70%, or minoxidil is frequently advised to protect the surrounding hair and avoid a patchy result later. The placement method makes no difference to this: it is about the biology of the untransplanted hair.
Written by Felix Rowan. Medically reviewed by Dr Omar Haddad, MBBS, ABHRS.
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