dhi hair transplantation

Dhi Hair Transplantation

Dhi hair transplantation technique (hair implantation with a pen) was developed by Dr. Young Choi back at the begging of 1990. This method of graft implant has been popular worldwide, especially in Far East Asia. There are a few different names of this technique, such as Choi implanter pen, hair implanter pen, hair transplant pen, and no-touch hair transplant. Dr. Hakan Doganay is a leading specialist in the pen transplant method in Turkey. He has been successfully transplanting since 2009. 

Unfortunately, together with its popularity in our country, the method gained an incorrect name too. DHI is the initial letters of a company name in Greece ‘Direct Hair Implant’ which practices pen transplant. There is no such technique as Dhi.  We realize that the term is inappropriate, although we will refer to it further in this article to explain technical moments because it is commonly used.

Since 2009 till today we have been achieving excellent results by the pen hair transplant method; compared to FUE hair transplant the Dhi has been more successful.  Together with the popularity of the FUE method the Dhi gained rapid demand too. However, it is worth remembering that Dhi hair transplant is not a special application of FUE. The technique like FUT was also successfully used within for many years. Unfortunately, not many doctors can succeed in pen transplanter method because it requires detailed technical knowledge and know-how. The other reason for the low interest of this method in past is the high cost of the equipment.

What is Dhi Hair Transplantation?

Dhi hair transplanter pen was invented by Dr. Choi. It is a spring-like tool similar to a regular pen,  also called as an implanter pen. Opening all channels at once makes this method different from the others. Once a channel is opened the ready graft is implanted simultaneously. This technique, if properly implemented, can be referred to best hair transplants compared to the rest ones. Preparation for Dhi hair transplant is similar to other methods, no extra activities are required. You can find more details in our article named hair transplantation procedure

Pen Types and Technical Information About the Pen Hair Transplantation

Pen hair transplantation is the best method of implanting hair, that provides excellent results if operated correctly. It is essential to understand the full technical side of the procedure, otherwise, the outcome may be disappointing. The pen implanters operated in hair transplantation can be divided into two major groups

1) Sharp Needle Implanter

All pens offered in Turkish market are in this group. They are operated by stick and place technique.

  1. Choi Implanter Pen. Preferred choice in Turkey
  2. KNU Implanter
  3. Lion Implanter Pen: The needle tip is relatively wider comparing to others
  4. OKT Implanter Pen
  5. HWANG Implanter: the only sharp-tipped implanter with depth control (stopper). Not used in Turkey. The needle is sharp both inside and outside. It is the most sharp-tipped implanter, moreover, its needle wall is the thinnest.

Except for Hwang, there are distributors of listed brands in Turkey. Choi Implanter Pen is a pioneer in our country. Its hair implant technique is called Choi hair transplant. Despite the slight diversity of the mentioned pens, the main working principle remains the same.  

implanter pen

On the picture above you can the difference between regular pen and Huwang’s sharp tipped pen with stopper.

2) Dull Needle Implanter (DNI)

The model is not performed in Turkey yet. It is a dull and wide tipped needle. In the DNI case, the channel is pierced, then the root is implanted by another pen. K.E.E.P, a pen developed by Dr. Koray Erdogan can be added into this group. The classic dull needle is different from a regular implanter; since the graft set inside of the needle is placed manually by forceps.

Differences Between Sharp and Dull  Needle Implanters

Please find in the below chart with the differences between Sharp and Dull Needles.

Sharp Needle ImplanterDull Needle Implanter
Graft ImplantStick and place methodImplant into previously pierced channels
Needle Incision SizeNeedle and channel sizes are same
The open channel can be smaller than the needle. Example: for 0,9 mm channel 0,8 mm needle
Determined during grafts implanting

Determined before implanting the grafts
Implant ProcessFastRelatively slow
Needle Tip ChangeNeedle is changed when it gets sharp lessNo need for needle change
Bleeding and Root PoppingLittleHeavier
Needle Slot DiameterTight. Generally 0,2 mmWider (Generally 0,35 mm)
Stopper Depth ControlRemains only in Hwang ImplanterAbsent
Pros/ConsLong graft should be taken out of the slit holding its top, otherwise implanted graft can be damaged. Thicker grafts can be destructed when implanted to tight channel.Damage risks are low

Chemical disinfectants, like Saydex or if possible Ethylene Oxide should be used for needle sterilization. We do not apply dry air sterilizers such as autoclaves or ovens because they damage needle structure and affect sharpness.

What is Implanter Pen and How it is Used?

Here we will describe the Dhi hair transplantation method. You can find more information about extracting grafts in our article the FUE grafting implant technique .

As previously mentioned the implanter pen is a regular pen and spring-like looking tool. Its protection layer is made of Teflon that thrives sterilization resistance up to approximately 130-140 degrees. The pen consist of 5-6 interbedded systems. Needle tips are located at the very end of the tool. They look the same to injection ones, however, their tip is vertical and slit. This helps to place grafts inside of the tip slits before implantation.  To operate quick and synchronous 4-6 implanter pens are needed during surgery. There are 3 stages of Dhi hair transplantation

a) Placement of Hair Roots into the Pen

Hair follicles are swiftly placed one by one into the needle tip of the pen by surgery assistants. Touching graft roots is forbidden; the hair should be pulled out by forceps and slid carefully into a slit. The grafts must not remain in the pen for a long time because they may dry inside. If necessary, the isotonic spray is applied to moisten the pen.

b) Replacement of Empty and Filled Pens

To prevent any pinprick accidents full coordination between the doctor and the assistants is expected during the replacement of empty and filled pens. In other words, the doctor places empty pens with the needle pointed towards him, while the assistants locate filled pens perpendicularly. There should be a 30-40 cm distance between full and empty pens. Thus the synchronous operation is achieved in Dhi hair transplantation; moreover, neither doctor’s nor assistants’ fingers are injured by the needles.

The other method option is when the doctor operates only with a hand wrist while the arm is in a stable position. Here the third assistant takes away an empty pen placing a filled one instead between doctor’s thumb point fingers. This makes the Dhi hair transplantation procedure much faster. Besides, the doctor’s hand is less tired due to reduced movements. Thus, the outcome is more successful.

C) Implant of the Grafts Placed in the Pen by the Doctor

The grafts should be placed in the pen needles. Then the pen is pointed to the hairless skin area at an appropriate angle; the skin is pierced by the needle tip. Once the pen top button is pushed, the hair is slid by a thin needle into the slit. Simultaneously, the spring system enables the needle to withdraw off the skin and come back to its start position. This is how the implantation of graft is operated. It is important to have neck relaxed otherwise bleeding may increase due to vascular compression.

The doctor should operate with a pen naturally. The pen is placed between the thumb and index finger, the rest fingers (3rd, 4th, and 5th) assist additionally. This filled pen pierces the skin to implant the graft. The top button of the pen is pushed by the index finger (to slid and implant the root). Simultaneously the pen should be pulled out of the skin quickly when the graft is implanted. The doctor easily gets accustomed to this operation rhythm and the Dhi hair transplantation becomes an automatized procedure.

Dhi Hair Transplantation and 7 Golden Know-How

Particular know-how helps to get a very successful outcome of the pen transplant method. Throughout our experience, we determined the special techniques and would like to share them with people willing to do the hair transplant operation. We collected 7 know-how for you, let us take a look at them. 

1- Diameter of the Needle Tip

All needle tip brands in the market offer a diameter between 0,6 and 1,8mm. We operate with 0,6 / 0,8 and 1mm diameter tips at the Fue hair transplant. We don’t think that bigger needles can provide sufficient frequency and natural look of the hair. Here are the specifications of these needles:

  • 0,6 mm: is generally used for single graft eyebrow transplant
  • 0,8 mm: can be used to implant one of two follicles
  • 1 mm: is used to implant 2-3-4 grafts

Pen producers paint the top of the pen with a specific color (green, red, blue, pink) which represents a certain needle tip diameter. This significantly simplifies our job as it helps to identify the pen immediately. Below you can see an example of sharp-tipped hair transplantation pens used in our country. The needle tips are 0.6, 0.8 and 1 mm. Our suppliers produce a variety of needles with the diameter up to 1,8 mm but we do not find appropriate using tips bigger than 1 mm in diameter for Fue hair transplant.

implanter pen

On average, 700-1000 grafts can be implanted with a pen needle. However, this number varies because people have different skin elasticity. If the skin cambers and pop out the grafts during transplantation, another needle tip should be applied. All in all, needle tip loses sharpness after every operation.

2- Width of the Needle Slits

A very tight slot can cause damage to the placed on the needle hair graft when transplanted, while a wide slot causes the decline of the graft before the implantation starts. The diameter of slits must vary between 0,2 and 0,3 mm. In the picture below you can see 1 mm diameter needles in high resolution; they are produced by 3 different companies. The 1st needle has a wider slot and the hair root section inside of the needle is wide too (called bevel). In our opinion, this model is the most preferable in terms of graft healthiness. Unfortunately, it is not ethically correct to share this Dhi needle producer details.

hair implanter

3- Pen Needle Length

The depth is one of the most important factors for a hair graft implant. Some implanters have no depth control. Needle length should be adjusted according to the hair in advance. It is necessary to regulate and correct needle length to graft size.

The standard size of the pen needle is around 7mm. This length can be adjusted according to the graft hair size. If the bleeding is more intensive than expected, it means that the needle length should be reduced. When the standard length 7mm is set to 6,5 or 6 mm, bleeding stops immediately. In opposite, if the needle size is shorter, the graft remains unimplanted on the skin surface and may be declined. Finally, if the graft implanted too deep, there is a risk that the root does not grow; or the planted hair shape defects.

A mathematical ratio should be determined between the needle and the graft length. Needle size is to be 25-30% longer than graft size. For example, application should be as follows:

  • Graft size 6 mm – needle size is 8 mm (25% longer)
  • Graft size 5 mm – needle size is 7 mm
  • Graft size 4 mm – needle size is 6 mm (33% longer).

An experienced doctor can easily do adjustments properly after a few tests

4- Length of the Wire that Pushes Graft into the Skin

This wire must not get over the Teflon spiral. If it comes out when the pen top is pushed or if it is easily visible, this means that the wire not only touches the graft’s top but also contacts the hair itself. As a consequence root may be defected. This wire should not be externally visible. In the meantime, it should not be placed very high as well. The wire has to remain on the Teflon protector level. The following picture clearly illustrates the above situations:

dhi hair implant

5- Placing the Needle on the Skin and the Implanting Depth

There is no such problem with stopper (depth control) implanter. The implanter needle without a stopper should not be completely inserted into the skin. Implanting about 1 mm in is enough, otherwise, graft root is considered to be placed too deep. A lot of practice is required to get appropriate skills in this technique. Once the hair graft is placed into the skin the pen must be pulled off immediately. As far as we know, there is no depth control implanter practice in our country. To operate synchronically a doctor must have sufficient experience. It is worth mentioning again that placing graft too deep causes the hair not to grow.

Here are the consequences of too deep graft implantation

  • a) Folliculitis and Cyst: Small inflammations and sebaceous glands called cysts can occur at the hair roots.
  • b) Curly hair growing
  • c) Recess at the hair roots
  • d) Intensive bleeding after the operation
  • e) The decrease in hair growth volume

As a result, the regulation of proper depth for the Dhi hair transplantation is one of the most significant stages of the operation.

6- Direction of the Needle When Placing a Graft

According to our experience, the needle slot must be directed down (towards the skin) to achieve a more successful outcome. While a sharp part of the needle is inserted into the skin, the needle angle gets a slight horizontal position. The depth can be controlled better this way as well. By implanting via current method, the merge of hair graft with fatty tissue and capillary vessels is just excellent. It is also more advantageous in terms of depth control of injecting the needle in scarred and vertex areas.

7- Stretching the Skin

The pressure occurs when the needle enters the skin in case of a pen implant method. This pressure can cause popping out of the other hair grafts. To decrease the risk to a minimum, the doctor or assistants should stretch the haired skin. The assistant pulls the skin in general and the doctor stretches a particular implant area. The stretching is especially important in front zones. Additionally, stretching helps to decrease the angle of inserted hair graft and achieve a more horizontal direction of the hair.

Unexpected Situations that May Occur after DHI Hair Transplant

The Dhi hair transplantation is not that easy as explained by theory. Sometimes, the operation goes like a knife through the butter but can result in undesired outcomes. We will introduce a few causes with suggestions further.

  • Bleeding: If the bleeding is more extensive than expected, the patient’s sitting position should be checked. Bleeding increases if the neck is under the pressure due to a sitting pose. Once the neck position is changed, bleeding stops. The ideal sejant for front area transplant is 45 degrees while the top of the head requires 60-70 degrees. We also mentioned above that the needle length can cause bleeding.
  • Popping: During the implantation process, earlier transplanted hair grafts around should not pop out due to the pressure.   in the Dhi hair transplantation operation, it is the least desired situation. If popping occurs, the needles should be replaced immediately. The second moment to be paid attention is the skin elasticity; the problem is commonly met among elder people, those who actively sunbathed or have scars. Skin must be stretched carefully during implantation surgery to prevent the popping. Additionally, the needle has to firstly slit the skin softly, then be injected from a certain angle. In this case, the needle is inserted deeper into the skin and the pressure is reduced.
Dhi Hair Transplantation on Scar Area

Among people willing to undergo the Dhi hair transplant are those, who have scars from the FUT method or gone though accidents like a car crash. Hair transplantation in the injured area is different from regular implantation. This is because the skin here is rougher and more pressure is needed to insert the needle. We find it more appropriate to make a channel for the graft by needle tip first on the scarred skin. Both, hypodermic needle or the empty pen needle can be implemented. Special attention must be paid to opening a proper channel suitable to the hair graft.

Later on, the channel made and graft implanted by the standard Dhi hair transplantation method. All in all, these techniques help to prevent graft popping during the surgery.

What can be Achieved by the Dhi hair transplantation?
  • Increase the density of rare hairs by unshaven hair transplantation method
  • The best results at the Beard hair transplant are achieved using the Dhi.
  • The Dhi is the ideal technique for whisker and beard hair transplantation, we give detailed information in our other article.
  • The best hair transplant method for women which does not require shaving.
  • It is certainly the best option for eyebrow hair transplantation. It is easier to determine the right angle and very thin needle-like 0,6 mm can be used. There is some know-how about eyebrow transplantation. You can find it in our article dedicated to eyebrow transplant

What are the benefits of the Dhi Technique?

The pen hair transplant method is one of the best as mentioned previously. It has many advantages compared to the classic hair transplantation method.
There is less bleeding. The after operation look is considerably nice.
Due to a very thin needle, no scar is left on the skin at the hair root.
One of the major factors is the implantation angle in getting the most natural look outcome. The angle is easily regulated by the pen method. Therefore, you can get a very natural look of the hair, so that it is hard to recognize the transplanted hair.
The risk of drying graft is higher in the classic Fue method.
If operated carefully, the Dhi causes less damage to the graft roots comparing to the Fue.
If preferred and if the number of grafts is sufficient, more dense hair transplantation can be made.
The implant with the Dhi is performed by piercing the skin, while transplantation with the Fue requires cutting, which injures the skin and leaves wounds. All of us ever been put ourselves on a drip at least once in life. Have you ever saw any sign of it after recovery? The same happens with the pen method, no defects are left and it is a significant benefit.
Comparing to the channel technique no adrenalin needs to be injected to decrease bleeding. There is also no need for isotonic liquid or saline serum to swell the haired skin. Therefore swelling after the hair transplant operation is very little. Ultimately, there is no necrosis-like effect due to adrenaline injection in the Dhi hair transplantation.
Comparing to other methods, the shock popping number is considerably low.
(the reason why adrenaline is not used)

Is the Dhi Hair Transplant Procedure Expensive?

Hair transplant of pen implanter is more expensive than other methods, and the cost of the equipment is higher as well. Here is a list of reasons:

  • The needle of the pen implanter is single-use. It absolutely must not be used in another patient. Even if you try to re-use the needle, it is not possible because it loses sharpness after some amount of implanted grafts. Approximately 8-10 needles are required to transplant around 2500 grafts. The average cost of a needle is 25 USD and for one procedure at least 8 needles are needed. The total price of these 8 needles is 200 USD. On the other hand, in channel method (FUE) blades which cost few cents are used. In addition to that, a pen implanter costs around 150 USD without a needle. 4-6 pens are needed for one surgery (implanter pens are not disposable). The Dhi transplant is more expensive compared to the FUE
  • Qualified doctor’s assistants are required for the Dhi hair transplantation. In many cases, the reason for unsuccessful outcomes is the lack of the technical knowledge and experience of a doctor and his assisting personnel. Assistant placing grafts into the pen should be highly qualified, which impacts the total surgery cost.
  • If we are not mistaking, some clinics offer a transplant of 5000-6000 grafts per day via the classic method. However, transplantation of more than 2000-2500 grafts with pen implanter at once is not appropriate. Therefore, implanting 5000-600 grafts via the pen method may take up to 3 days.
  • Based on the reasons listed above, it is normal that the Dhi hair transplantation is a little more expensive than the classical method. Due to legal restrictions, we can’t publish our rates on the website. Please contact us to get the price at 0090 533 247 1990 ( available on WhatsApp).

What is the Feedback of People Who Had the Dhi Hair Transplantation?

We already mentioned the advantages and disadvantages of this method. You can easily access to many forums of people who experienced transplantation on the internet. You will find a lot of forums with comments and results of Turkish and foreign patients who had been operated by Dr. Hakan Doganay. As an example, you can take a look at our YouTube video about a patient who had a hair transplant. There are also other videos on our channel

What Should be Paid Attention to When Searching Information About the Pen Implanter Method?

The Dhi hair transplantation method first started operating by Dr. Hakan Doganay in Turkey yet many clinics promote it as a new technique nowadays. We would like to share some questions for one, who is thinking about the Dhi.

  • Is the doctor active in the pen implanter technique? If yes, what is his experience?
  • Is the operation made with pen implanter from the beginning to the end or any other tools are included?
  • Is assisting personnel qualified enough for the pen implanter transplantation? Where did the assistants get an education?
  • Where can I examine the outcomes of the hair transplant? Are there any real examples?
  • Are the single-use needles sterile?

Frequently Asked Questions

Let us answer most common questions about the topic

What are the Disadvantages of Pen Hair Transplant?

Together with the benefits of the Dhi hair transplantation method, there are also some disadvantages. Here they are:
As mentioned previously, the Dhi method requires special technique knowledge. If a doctor does not have enough technical skills, the result of the transplantation may be disappointing.
It is the most expensive transplantation method, compared to others.
The surgery should be operated by a doctor only. In the channel method, the assistants may help to stretch the skin at the sides. If a transplant is made by the pen method, only a doctor must stretch the skin. Transplantation of more than 2000-2500 grafts is not acceptable in a single session

Is the Dhi Technique Better Than the FUE?

In short, our answer is yes. There are many benefits of the Dhi technique comparing to the FUE. The most significant ones are dense and unshaven hair transplantation opportunities.

Does the Dhi Hair Transplant Hurt?

Local anesthesia is applied before the operation, so you do not feel any pain during the surgery. You can find more information in the article about the best hair transplantation method


  1. Survival Rate According to Grafted Density of Korean One-Hair Follicular Units with a Hair Transplant Implanter: Experience with Four Patients American Society for Dermatologic Surgery, Inc. Dermatol Surg 2006;32:815–818
  2. Graft Placement Using the Dull Needle Implanter (DNI) Technique https://www.ishrs-htforum.org/content/27

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