Compiling research for anyone considering a hair transplant. I've spent a lot of time on this because I'm potentially considering it in the next 2-3 years, so sharing what I've learned.
The two main techniques currently are FUE (Follicular Unit Extraction) and DHI (Direct Hair Implantation). Both are modern refinements of FUE — in both cases individual follicular units are extracted one at a time from the donor area (usually the back of the scalp) and implanted into the recipient area.
FUE: follicles are extracted and stored, then implanted using a punch tool to create recipient sites first, then the follicles are inserted. The surgeon has control over angle, depth, and direction at the implantation stage. Well-established technique with a large evidence base.
DHI: uses a Choi implanter pen which simultaneously creates the site and inserts the follicle in one step. Theoretically reduces the time grafts spend outside the body, which may improve graft survival. The angle control is slightly less flexible than standard FUE.
Which is better? The honest answer is: the surgeon matters more than the technique. A skilled surgeon doing FUE will outperform a mediocre surgeon doing DHI every time. Both techniques can produce excellent results in the right hands.
Key things to research before committing: the surgeon's track record (not the clinic's — the specific surgeon who will be performing your procedure), the graft count relative to your current loss and future projected loss, whether you'll be on fin post-transplant (if not, you're not protecting the non-transplanted hair and you'll eventually look unnatural).
Turkey is popular for price reasons and has some very good surgeons, but also a lot of mill clinics doing volume procedures. Do thorough due diligence. The HairRestorationNetwork forum is the most useful resource I've found for specific clinic reviews.
The "stabilise your hair loss before transplant" point is crucial and under-emphasised. If you get a transplant while your native hair is still actively miniaturising, in 5 years you'll have transplanted hair surrounded by lost native hair and you'll look strange. Most reputable surgeons won't operate on someone who isn't on fin unless their hair loss has been stable for 2+ years. And even then, future planning for a second procedure is important.
What's the typical graft count for hairline restoration? I have a NW2/2.5 pattern and I'm wondering if it would even be a significant procedure.
A hairline restoration at NW2 is typically 1500-3000 grafts depending on how far back the temples have receded and the density desired. It's a relatively minor procedure in terms of donor use, which is good because it preserves donor for any future work. At NW2-2.5 on fin and min, you might also find that you stabilise and regrow enough that a transplant feels less urgent. Give the meds 12-18 months before committing to surgery.