Choi pen diameter: 0.6, 0.7 or 0.9 mm for your hair?
Choi implanters come in 0.6, 0.7 and 0.9 mm. The right one depends on how thick your grafts are, and the difference shows first at the hairline.
Which diameter is right for you
The diameter is chosen from your graft thickness, not from a price list. Most DHI cases use three implanter sizes: 0.6 mm for single-hair grafts along the hairline, 0.7 mm for two-hair units in the mid-scalp, and 0.9 mm for the thickest three-hair units further back. The needle must match the graft it carries. Too narrow and the follicle is crushed during loading; too wide and the channel stays open, which invites bleeding and lets the graft shift in the first hours.
Why the hairline needs the narrowest needle
A hairline built with 0.9 mm implanters reads as planted from two metres away, because each opening leaves a visible ring of scalp around the shaft. Along the first two or three rows we use 0.6 mm pens loaded with single-hair grafts only, keeping the channel close to the diameter of a natural follicular opening. It is slower work, fewer grafts per hour, and it is one honest reason DHI is priced at €2,300 rather than €1,800 for sapphire FUE.
How we measure before choosing
Hair calibre varies far more between people than patients expect: a fine Northern European shaft can measure around 55 microns while a thick Middle Eastern one approaches 90. We measure it with a trichoscope at consultation, count how many hairs sit inside each follicular unit, and pick the pen sizes from those two numbers. Two men with identical Norwood grades can need completely different implanter sets, which is why a plan written from photographs alone is only a starting point.
What to ask before you book
Ask which diameters the clinic stocks and how many implanters are opened for your case. A single pen pushed through four thousand grafts blunts, and a blunt needle tears tissue rather than parting it. We open a fresh set for every patient and change tips through the session, and the sterilisation records behind that are part of what Temos accreditation audits. If a quote will not answer the question in writing, message us on WhatsApp at +905402555055 and compare the two replies.
The Ones People Actually Ask.
Can 0.6 mm implanters be used for the entire transplant?
No, and it would harm the result. Forcing a thick three-hair graft through a 0.6 mm pen damages the follicle. The narrow size is for single-hair grafts at the hairline and temples; the interior needs wider pens matched to the units placed there.
Does a smaller Choi needle mean less scabbing?
Slightly. Narrower channels bleed less and crust less, so the recipient area usually clears a day or two sooner. The bigger factor is still how the area is washed during the first week.
More On Hair.
Grafts start losing viability after about two hours out of the body. Here is what happens in those hours, and why the…
What is the safe maximum number of grafts in one session?Between 4,000 and 5,000 grafts is the honest ceiling for a single day, and the limit is set by your donor area and…
How many grafts per cm²? The density that decides coverageNative scalp carries 70 to 100 follicular units per cm². A transplant that reaches 40 to 45 in the hairline already…
Channel angle and direction: why a transplant looks naturalHair leaves the scalp at 15 to 25 degrees at the hairline and spirals in the crown. Copying those angles channel by…
What Stands Behind The Plan.
