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Gender & Other Considerations in Choosing Hair Restoration Treatments

Human hair emerges from the scalp in groupings that constitute the visible part of the histologic structure known as the follicular unit (FU). This anatomical unit encompasses terminal hair follicles (with a diameter exceeding 40 microns), vellus follicles (less than 40 microns), sebaceous glands, arrector pili muscles, perifollicular dermis, adipose tissue, eccrine coils, and intricate neural and vascular networks.

Typically, scalp FUs exhibit 1, 2, 3, or 4 terminal hair follicles, and the specific proportions dictate the overall hair density for an individual. In the midoccipital scalp of Caucasians, FU density generally falls within the range of 65-85 FU/cm2. The majority of these FUs consist of 2 hairs, followed by 3- and 4-hair FUs, with only 10% to 20% having a single hair. It is noteworthy that FU density (FUs/cm2) and hair density (hairs/cm2) exhibit variations among individuals, between different scalp zones, and across diverse racial backgrounds. For instance, Asian and black skin tend to have lower hair density compared to Caucasian skin, with counts ranging from 154-162 hairs/cm2 in Asians, 148-160 hairs/cm2 in blacks, and 214-230 hairs/cm2 in Caucasians.

Accurate assessment of hair and FU density, facilitated by high-magnification devices equipped with quality optics such as dermoscopes or macro-video cameras, is crucial. This evaluation aids in determining the available donor hair for transplantation and estimating the size of the donor strip required for harvesting. A rule of thumb in this process is to employ advanced imaging tools to ensure precision in measurement and analysis.

How is Male vs Female Alopecia Different?

  • Male Alopecia

Androgenetic alopecia (AGA) stands out as the predominant indication for hair transplant surgery. This condition is characterized by progressive androgen-related hair thinning following a distinct clinical pattern. The severity of AGA can be classified using the Hamilton-Norwood classification system, illustrated in this picture. A recent systematic review indicates satisfaction rates ranging from 90% to 97% and graft survival rates of 85% to 93% among transplanted patients with male AGA. Beyond mere contentment with their appearance, many patients also report enhancements in psychological well-being and self-esteem.

It's crucial to understand that hair transplantation doesn't entail a net increase in new hair; rather, it involves redistributing existing hair from the donor zone to the recipient zone. Given the lifelong nature of AGA and the inability of hair transplantation to alter its progression, surgeons must strategically plan the cosmetic distribution of transplanted hair to ensure a consistently natural look. Patients should be informed about the necessity of a long-term plan for future hair loss, typically involving a combination of medical treatment and one or more surgical procedures. Successful medical therapy plays a pivotal role in achieving the maximum long-term density from a hair transplant.

Oral finasteride and topical minoxidil, both FDA-approved, serve as the primary medications for male AGA. Finasteride, in particular, halts hair loss in most men and results in partial regrowth in 66% of patients. Continuous use for at least 6 months is recommended to assess its full effect. Dutasteride, used off-label for non-responders to finasteride, requires caution due to potential sexual side effects. For those averse to oral finasteride, topical finasteride is an off-label alternative. Combining oral finasteride with 5% topical minoxidil appears to yield better results than monotherapy.

Beyond pharmaceutical interventions, alternative therapeutic options include platelet-rich plasma (PRP) injections and low-level laser therapy (LLLT). Clinical trials on PRP generally report positive outcomes. However, further research is needed to determine the optimal PRP regimen, typically involving treatments at 4- to 6-week intervals. LLLT, utilizing red light in the 635-678 nm wavelength range, has been shown to enhance hair density safely and effectively. Administration methods include helmets, caps, bands, or combs, with session durations ranging from 10 to 30 minutes and frequencies of 2-7 sessions per week.

While combinations of the aforementioned medical therapies are likely to be synergistic, additional clinical trials are imperative to confirm the efficacy of such combination therapy.

  • Female Alopecia

Women can manifest three distinct hair loss patterns, each requiring nuanced consideration:

  • Ludwig pattern, marked by diffuse central thinning across the mid-frontal scalp while maintaining the anterior hairline;

  • Androgenic pattern, analogous to male pattern hair loss;

  • Diffuse unpatterned alopecia, characterized by generalized hair miniaturization. Transplanting hair in patients with diffuse unpatterned alopecia poses challenges, primarily due to the diffuse nature of hair loss, which restricts the availability of donor hair. Moreover, the overall thinning of the recipient scalp in this condition complicates achieving satisfactory cosmetic improvements. On the contrary, women exhibiting androgenic or Ludwig patterns are generally considered suitable candidates for hair transplantation, although a meticulous evaluation of the donor area is imperative.

Similar to male androgenetic alopecia (AGA), hair transplantation for female pattern hair loss necessitates a combined approach involving medical therapy to impede ongoing loss and potentially reverse hair miniaturization. Topical minoxidil is the first-line and sole FDA-approved medical therapy for female pattern hair loss, with recommended usage of 1 ml of 2% solution twice daily or 1 ml of 5% solution or foam once daily. Off-label oral antiandrogen options, such as finasteride, spironolactone, cyproterone acetate, and flutamide, exist, but their efficacy lacks strong supporting evidence, and sexually active premenopausal patients require contraception. Low-dose oral minoxidil (ranging from 0.25 to 1.25 mg/day) has shown promising results, although further randomized studies are necessary. Positive outcomes in clinical trials for both androgenetic alopecia (AGA) and female pattern hair loss have been observed with platelet-rich plasma (PRP) and low-level laser therapy (LLLT). However, ongoing research is crucial to establish their effectiveness conclusively.

What are the other considerations?

Selecting suitable candidates for hair transplantation involves a mandatory pre-transplantation consultation, during which five key factors are assessed to determine candidacy.

1. Age and Personal/Family AGA History

Due to the polygenic inheritance of androgenetic alopecia (AGA), patients with a family history of hair loss are more predisposed to severe AGA. The patient's personal history, including the duration and rate of hair loss, is crucial for estimating the extent of expected hair loss. Hair surgeons should exercise caution when considering hair transplants for men in their early 20s, as progressive hair loss may lead to unsightly patterns. Patients of this age may not fully grasp the commitment required for future sessions, making it advisable to prioritize medical therapy initially and evaluate the response before proceeding with transplantation.

2. Response to Medical Therapy

The success of medical treatment is paramount in halting hair loss progression and ensuring a sustained, long-term transplant outcome. The net perceived density of transplanted hair depends on the amount of transplanted hair minus the rate of ongoing hair loss.

3. Donor Characteristics

The availability of donor hair is a critical factor in hair transplantation. Harvesting enough follicles to address balding without depleting the donor area is key. Parameters such as follicular unit (FU) density, hair density, and hair thickness are evaluated. Patients with normal-to-high FU density (≥65 FU/cm²) and thick hair (≥50-60 microns) are considered good candidates, while those with diffuse hair loss, low FU density (≤40-50 FUs/cm²), and donor hair miniaturization (≥20% miniaturized) are less suitable. Coarse and curly hair tends to provide better coverage. In cases where the donor area is depleted or unsuitable, artificial hair implantation (synthetic fibers) can be an alternative, although its use is controversial and prohibited by the FDA due to potential adverse reactions.

4. Degree of Baldness

Patients with moderate to advanced baldness (Norwood III-V and Ludwig II) are typically the best candidates. Those with mild AGA (Norwood II and Ludwig I) might benefit from medication first to prevent hair loss progression. Patients with advanced baldness (Norwood VI-VII and Ludwig III) should be evaluated on an individual basis, considering sufficient donor area density. The goal is not a full head of hair but rather framing the face, and successful outcomes can be achieved with less than the original recipient area density.

5. Patient’s Expectations

Surgeons should transparently communicate the surgery's expectations, the limited nature of donor hair, the impact of ongoing hair loss, and the importance of adjuvant medical therapies. Managing patient expectations is crucial, as those with unrealistic expectations or psychological concerns, such as body dysmorphic disorders, may not be ideal candidates for hair transplantation.

In essence, a comprehensive assessment, open communication, and realistic expectations are essential for identifying suitable candidates for successful hair transplantation.

What are the most common treatments?

1. Hair Transplantation: This involves taking hair follicles from a donor site (often the back of the head) and transplanting them to areas with thinning or no hair. Hair transplantation is a surgical procedure designed to address hair loss by redistributing hair follicles from a donor area to areas of the scalp experiencing thinning or balding. This procedure is particularly effective for individuals experiencing androgenetic alopecia, commonly known as male or female pattern baldness.

What are the Procedures?

  1. Donor Site Selection: The donor site is typically chosen from areas where hair follicles are genetically programmed to be more resistant to the hormone dihydrotestosterone (DHT), a major contributor to hair loss. The back and sides of the scalp are common donor areas due to their DHT-resistant nature.

  2. Follicular Unit Extraction (FUE): In FUE, individual hair follicles are meticulously extracted from the donor area using a specialized punch tool. This technique minimizes scarring and allows for a more natural-looking result. FUE is preferred by some patients who want the flexibility to wear shorter hairstyles.

  3. Follicular Unit Transplantation (FUT): FUT, also known as strip harvesting, involves removing a narrow strip of scalp from the donor area. This strip is then dissected into individual follicular units, each containing one or more hair follicles, for transplantation. FUT may leave a linear scar, but advancements in surgical techniques aim to minimize scarring.

  4. Recipient Site Preparation: Once the follicles are harvested, tiny incisions are made in the recipient site (the area with thinning or no hair) where the transplanted follicles will be placed. The angle, depth, and density of the incisions play a crucial role in achieving a natural-looking outcome.

  5. Follicle Implantation: The harvested follicles are carefully implanted into the recipient site, paying attention to the natural growth patterns and angles of the existing hair. This meticulous approach ensures a seamless integration of the transplanted hair with the patient's natural hair.

2. Platelet-Rich Plasma (PRP) Therapy: This non-surgical option involves drawing a patient's blood, processing it to concentrate the platelets, and then injecting the PRP into the scalp to stimulate hair growth.

Platelet-Rich Plasma (PRP) Therapy stands as a revolutionary non-surgical approach to hair restoration, harnessing the body's own healing abilities to stimulate hair growth. This technique has gained popularity for its minimally invasive nature and promising results.

What are the Procedures?

  1. Blood Draw: The process commences with a small blood draw from the patient, typically taken from the arm. This blood sample is then processed to separate the platelet-rich plasma from other components.

  2. Centrifugation: The drawn blood is subjected to centrifugation, a process that separates different components based on their densities. This centrifugal force isolates the platelets, which are rich in growth factors and other regenerative elements.

  3. Platelet Concentration: The result is a concentrated plasma containing a higher-than-normal concentration of platelets. These platelets contain growth factors such as platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), which play key roles in tissue repair and regeneration.

  4. Injection into the Scalp: The PRP, now enriched with growth factors, is carefully injected into the targeted areas of the scalp experiencing hair thinning or loss. The injection process involves a series of meticulous placements to ensure comprehensive coverage.

How PRP Stimulates Hair Growth?

  1. Cell Proliferation: The growth factors in PRP stimulate the proliferation of cells in the hair follicles, promoting the regeneration of dormant or weakened follicles.

  2. Blood Vessel Formation: VEGF in PRP encourages the formation of new blood vessels, enhancing blood flow to the scalp. Improved circulation is vital for delivering essential nutrients to the hair follicles.

  3. Collagen Production: PRP supports the production of collagen, a structural protein that provides a supportive framework for healthy hair growth.

3. Low-Level Laser Therapy (LLLT): LLLT uses low-level lasers or light-emitting diodes (LEDs) to stimulate hair growth. Low-Level Laser Therapy (LLLT) is a cutting-edge and non-invasive technique that employs the power of low-level lasers or light-emitting diodes (LEDs) to stimulate hair growth. Widely recognized for its convenience and minimal side effects, LLLT has become a popular option for individuals seeking to rejuvenate their locks without surgical intervention.

How LLLT Works?

  1. Bio-Stimulation: LLLT harnesses the therapeutic properties of low-level lasers or LEDs to penetrate the scalp's tissues. These devices emit light at specific wavelengths, reaching the hair follicles without generating heat or causing damage to the skin.

  2. Cellular Energy Production: When absorbed by the hair follicles, the light energy stimulates cellular activity and enhances the production of adenosine triphosphate (ATP), the energy currency of cells. This heightened cellular energy is believed to revitalize dormant or weakened hair follicles.

  3. Increased Blood Flow: LLLT has been shown to promote vasodilation, leading to increased blood flow to the scalp. Improved circulation ensures that essential nutrients and oxygen reach the hair follicles, creating an optimal environment for hair growth.

  4. Reduction of Inflammation: Some studies suggest that LLLT may have anti-inflammatory effects, potentially reducing inflammation around hair follicles and contributing to a healthier scalp environment.

What are the Methods of Application?

  • LLLT Devices: These devices come in various forms, including laser helmets, caps, combs, and hoods. Individuals can use these devices at home, making LLLT a convenient option for ongoing treatment.

  • In-Office Treatments: Some clinics offer in-office LLLT treatments using more advanced and powerful devices. These sessions are typically administered by trained professionals.


Clinical and experimental studies of transplantation of living hairs (1939)

Hair transplantation: Basic overview (2021)

The history of hair restoration surgery (1996)

The aesthetics of follicular transplantation (1997)

Distribution of human hair in follicular units (1999)

Dynamics between stem cells, niche, and progeny in the hair follicle (2011)


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