Hair Transplantation: Understanding FUE, FUT and DHI Techniques

Hair transplantation, also known as hair restoration surgery, is a surgical procedure in which follicular units are transferred from a donor area to a region of the scalp affected by hair thinning or hair loss. A follicular unit is a naturally occurring group generally containing one to four hairs and their associated follicular structures. The donor area is usually located at the back and sides of the scalp, where follicles are often less susceptible to the mechanisms responsible for androgenetic alopecia. The most common indication is androgenetic alopecia, which affects both men and women. Hair transplantation may also be considered in certain cases of stable scarring alopecia, particularly following burns, trauma or surgery. It is essential to understand that transplantation does not create new follicles. It redistributes the follicles available in the donor area to the regions requiring treatment. Hair transplantation also does not prevent the progression of hair loss in non-transplanted hair. A long-term management strategy should therefore be discussed with the physician.

The terms FUE, FUT and DHI are frequently used to describe hair transplantation techniques. However, they do not refer to three equivalent methods. FUE and FUT are two techniques for harvesting follicular units. DHI primarily refers to a method of implanting grafts into the recipient area.

FUE: Individual Follicular Unit Harvesting FUE (Follicular Unit Excision) involves individually extracting follicular units using a small cylindrical instrument called a punch. This technique does not require the removal of a strip of scalp. However, it leaves multiple small, dot-like scars that are generally discreet after healing. Excessive or uneven extraction may cause a visible reduction in donor-area hair density, a complication known as overharvesting.

FUT: Strip Harvesting FUT (Follicular Unit Transplantation) involves removing a strip of scalp from the donor area. The strip is then dissected to isolate the follicular units intended for transplantation. FUT may allow a substantial number of grafts to be harvested during a single session. However, it leaves a linear scar whose visibility depends on the surgical closure technique, individual healing and hair length.

DHI: Implantation Using an Implanter Pen DHI (Direct Hair Implantation) refers to an implantation method using an instrument known as an implanter pen. Follicular units are generally harvested using FUE and then inserted into the recipient area with this instrument. The implanter pen allows the practitioner to control certain aspects of graft placement, particularly orientation and depth. However, the available scientific evidence does not establish that DHI systematically produces greater density, higher follicular survival or more natural-looking results than other implantation methods.

The choice of technique should be based on an individual assessment rather than claims of commercial superiority.

Hair transplantation is primarily intended for individuals experiencing hair loss for whom transplantation may improve hair coverage. The preoperative assessment examines the cause of alopecia, its progression, the density and quality of the donor area, hair shaft diameter and the patient's expectations. Certain situations may require the procedure to be postponed or reconsidered, including: ongoing hair loss that has not been adequately assessed, active alopecia areata, uncontrolled inflammatory scalp disease, a medical condition that makes elective surgery unsuitable, unrealistic expectations regarding the outcome. In women, hair loss may be diffuse and may also affect the donor area. A specific assessment is therefore necessary to determine whether transplantation is appropriate. The decision must be based on a medical examination, potentially supplemented by trichoscopy, rather than solely on photographs of the scalp.

Before hair transplantation, a medical consultation is necessary to confirm the diagnosis and determine whether the procedure is appropriate for the patient. The physician assesses the patient's medical history, current medications, scalp condition and donor-area characteristics. The likely progression of alopecia is also considered, as non-transplanted hair may continue to thin after surgery. Surgical planning includes several important elements: the area requiring coverage, the estimated number of grafts, the distribution of follicular unit harvesting, the design of the frontal hairline, the realistic limitations of the expected outcome. Patients should receive clear, understandable information about the available techniques, potential scarring, complications, postoperative care, alternatives and the possibility of future procedures. The consultation also provides an opportunity to discuss medical management of the underlying alopecia.

Hair transplantation is generally a well-tolerated surgical procedure, but it carries potential risks. Common postoperative effects may include discomfort, swelling, crusting and minor bleeding. Pigmentation changes, visible or hypertrophic scars and persistent sensory disturbances may also occur. FUT produces a linear scar, whereas FUE results in multiple small, dot-like scars.

Complications in the Donor Area Possible complications include folliculitis, visible scarring, altered sensation and excessive reduction in hair density following overly extensive harvesting.

Complications in the Recipient Area Infections, folliculitis, prolonged erythema and temporary hair shedding have been reported. More rarely, severe complications such as skin necrosis may occur.

What Does the Scientific Literature Show? A literature review published by Liu and colleagues in 2025, covering 43 publications, reported overall complication rates of 1.2% and 4.7% in two large clinical series.

These figures should not be interpreted as the individual risk for any given patient, as the studies differ considerably in methodology and in how complications are defined.

Appropriate patient selection, careful harvesting, proper graft handling and high-quality postoperative follow-up all contribute to the prevention of complications.

Hair transplantation is generally performed as an outpatient procedure under local anaesthesia. The duration of surgery varies depending on the technique used and the number of grafts to be transplanted. During the first few days, patients may experience swelling, redness, crusting and scalp tenderness. Crusts generally diminish progressively over the first few weeks. Postoperative instructions typically cover scalp washing, protection of the operated areas, physical activity and monitoring of wound healing. These instructions should be adapted to the technique used and the recommendations of the medical team. Severe or increasing pain, spreading redness, purulent discharge, fever or unusual changes in skin colour require prompt medical assessment.

Hair shedding may occur during the weeks following a hair transplant. Although this can be concerning for patients, it does not necessarily mean that the grafts have failed. Two situations should be distinguished.

Shedding of Transplanted Hair. Following surgery, the hair shafts of transplanted follicles may temporarily shed. The follicles themselves may remain viable beneath the skin and gradually resume their growth cycle.

Shock Loss. The term shock loss generally refers to temporary shedding of pre-existing hair, particularly around the transplanted area or within the donor area.

This postoperative shedding may be associated with surgical trauma and temporary changes in the follicular growth cycle. Recovery depends on the initial condition of the follicles. Complete regrowth cannot be guaranteed, particularly when the affected hairs were already severely miniaturised. Unusual or persistent shedding, especially when accompanied by inflammatory symptoms, requires medical evaluation.

The results of hair transplantation are not immediate. After the initial healing phase and possible shedding of transplanted hair shafts, regrowth generally becomes noticeable around the third or fourth month. Hair density and appearance then improve progressively over the following months. A more complete assessment of the outcome is usually possible between eight and twelve months after surgery. In some patients, the result may continue to mature beyond this period. These timeframes are indicative and may vary according to individual characteristics, the treated area, the surgical technique and the hair growth cycle. It is therefore important not to judge the final result during the first few weeks after transplantation.

The concept of a hair transplant success rate must be interpreted carefully.

It may refer to several different outcomes: graft survival, the hair density achieved, the aesthetic appearance, patient satisfaction.

These measures are not interchangeable. A retrospective study published in 2024 in BMC Surgery evaluated 158 men who underwent FUE transplantation for androgenetic alopecia. The authors reported follicular survival exceeding 90%, with more than 85% of patients achieving a follicular survival rate above 95% at twelve months. These findings come from a single-centre retrospective study involving men only. They cannot therefore be generalised to all patients, surgical teams or transplantation techniques. A satisfactory outcome also depends on graft distribution, frontal hairline design, donor-area quality and the subsequent progression of alopecia. No technique guarantees a specific hair density or aesthetic outcome.

Hair transplantation does not cure androgenetic alopecia. Transplanted follicles generally originate from areas that are less susceptible to the mechanisms responsible for hair follicle miniaturisation. However, non-transplanted native hair may continue to become thinner and gradually disappear. This progression can alter the overall appearance of the result over time, particularly when transplantation is performed at an early stage of alopecia. Surgical planning must therefore take into account the likely progression of hair loss and the limited number of follicles available in the donor area. Depending on the clinical situation, the physician may also discuss medical treatments for alopecia, independently of transplantation. Hair transplantation should be considered as part of a long-term management strategy.

Hair transplantation redistributes follicular units from a donor area to regions of the scalp affected by hair loss. FUE and FUT differ in their harvesting methods, while DHI is an implantation technique generally associated with FUE. The choice of technique depends on numerous individual factors, including the type of alopecia, donor-area characteristics, the extent of hair loss, general health and the patient's objectives. Hair transplantation requires a prior medical assessment, clear information about potential risks and appropriate postoperative follow-up. Finally, no method guarantees a specific aesthetic result or prevents the progression of alopecia. Medical disclaimer This article is intended for general medical information only. It does not replace a specialist consultation or an individualised medical decision.