About Hair Growth
Hair in General
Hair has a great social significance for human beings. It can grow on almost every area of the human body except on the palms of the hands and the soles of the feet, but hair is most noticeable in people in only a small number of areas, which are also the ones that are most commonly trimmed, plucked or shaved. These include the face, nose, ears, head, eyebrows, legs, and armpits, as well as the pubic region. Hair is seen as an indicator of gender or aging; facial hair is one of the most visible differences between the male and female body, and while facial hair is a sign of puberty in men, white hair is an indicator of aging. Hairstyles can indicate social status, acceptance or rejection. For example, the Manchu Qing Dynasty, beginning in the late 17th century China, ordered all Chinese citizens to adopt Manchurian hairstyles by shaving the front of their head and adopting a queue; in Islam, women would cover their hair as a symbol of modesty; while heads are shaved in prisons and concentration camps as a sign of punishment. Although in today's society a shaved head is an acceptable hairstyle for men, healthy hair indicates vitality and youth, which may explain the reason why many people experiencing baldness seek hair restoration.
Hair has two separate structures: the hair shaft (the part we see above the skin) and the follicle (the part that is below the surface of the skin). The hair shaft is composed of strong, structural protein called keratin. This is the same protein that makes up the nails and the outer layer of the skin (Fig. 1.1).
Below the surface of the skin is the hair “root” or hair follicle comprised of several structures: dermal papilla, hair bulb, hair shaft, sebaceous gland and a tiny muscle.
The dermal papilla is made up of connective tissue and a capillary loop creating the place where hair production originates and where hair receives its nutrients. The hair bulb is located directly above the papilla; it contains a collection of epithelial cells interspersed with cells producing a pigment called melanin. Generally, if more melanin is present, the color of the hair is darker; if less melanin is present, the hair is lighter. This part is also called the hair matrix because it is responsible for the manufacture of the hair. The hair matrix is one of the fastest-growing cell populations in the human body, which is why some forms of chemotherapy or radiotherapy that kill dividing cells may lead to temporary hair loss.
Each strand of hair (hair shaft or hair fiber) contains three layers: medulla, cortex and cuticle. The medulla is the innermost layer found in large and thick hair. The cortex is the middle layer, which provides strength as well as imparts color and texture to the hair. The cuticle is the outermost layer made up of tightly packed scales that form an overlapping structure similar to the roof shingles and function as a protective coat over the cortex. Most hair-conditioning products attempt to affect the cuticle by making these scales lie flat, thus imparting a silky feel to the hair. Attached to the hair follicle is a sebaceous gland, a small sebum-producing gland found everywhere except on the palms, lips and soles of the feet. The purpose of the sebum, an oily and waxy matter, is to lubricate the skin and hair keeping them waterproof and protected from dehydration. More sebum is produced after puberty. The sebum production decreases throughout life, with greater reduction in women than in men. Also attached to the hair follicle is a tiny bundle of muscle fibers called the arrector pilli. When this muscle contracts, it causes the hair to stand up resulting in a phenomenon commonly known as goose bumps.
Unlike other mammals that shed or grow hair according to the season, in humans hair growth and loss are random and not strictly but somewhat seasonal. At any given time, in humans a random number of hairs will be in various stages of growth and shedding.
The three phases of hair-growth cycle are as follows: anagen, telogen and catagen. Anagen is the active growth phase during which the cells in the matrix are dividing rapidly, adding to the hair shaft. During this phase the hair grows approximately 1 to 2 cm (i.e., half to one inch) per month. The catagen stage is a short transition phase that occurs at the end of the anagen phase during which the hair follicle receives a signal to stop growing. Shortly after the hair growth stops, the dermal papilla contracts and releases the hair shaft from the follicle allowing hair to shed. The telogen phase describes the resting time for the hair follicle. During this phase, a secondary hair germ forms from a band of epithelial cells that moves upwards, often seen during graft dissection as a short, smaller version of the hair bulb.
Each hair follicle goes through 10 to 20 cycles in a lifetime, while each cycle lasts a different time: anagen lasts 3 to 10 years, catagen 2 to 3 weeks and telogen 3 to 4 months. This may explain why some hairs live longer than others, as the hairs on the back of the head may be programmed to survive for twenty 10-year cycles and live for 200 years. In the human scalp the cycles are not synchronized. Therefore, at any one time an average of 13% of the hair is in the telogen phase (with the thought that it can range from 4% to 24%), only 1% to 2% is in catagen and the rest (85% to 90%) of the hair remain in the anagen phase. About 25 to 100 hairs are shed normally each day (Fig. 1.2).
Some people have difficulty growing their hair beyond a certain length because they have a short active phase of growth. On the other hand, people with very long hair have a long active phase of growth. The hairs on the arms, legs, eyelashes and eyebrows have a very-short, active growth phase (one to seven months) explaining why they are so much shorter than scalp hair.
About Hair Loss
Humans are born with approximately 100,000 hair follicles on their scalp. Scalp hair only constitutes a small fraction (100,000 to 150,000 follicles) of the total count for the body (approximately 5 million follicles).
Figure 1.2: Hair growth can be divided into three phases: anagen (active growth), catagen (active loss) and telogen (resting phase). In the scalp, 90% of the hairs remain in the anagen phase. Catagen only lasts about two to three weeks and is characterized by the hair-shaft separation of the dermal root, and it is recognized by a thin connective tissue strand connecting the two. About 10% of the hairs are in telogen phase at any given moment, and this lasts about two to three months. Catagen phase is the shortest of the three phases and occurs prior to telogen. As the basal attachment becomes even more attenuated, the hair shaft detaches from the dermal root ultimately, resulting in the hair falling out (known as exogen). Scalp hairs are asynchronously in these three cycles at any given time.
Alopecia, or hair loss, is the medical term for the loss of hair from the head or body. Unlike intentional aesthetic depilation, alopecia is involuntary and often unwelcomed. However, sometimes hair loss may be caused by a psychological compulsion to pull out one's own hair (trichotillomania) or the unforeseen consequences of voluntary hairstyling routines: mechanical hair loss (traction alopecia) from excessively tight braids or burns (scarring alopecia) caused to the scalp from caustic hair relaxer solutions, both types of hair loss often seen in African-Americans. When hair loss occurs in only one section and appears as bald patches, it is known as alopecia areata. Most often, traction alopecia can be treated with hair transplantation, while a dermatologist must treat other types of scarring and non-scarring alopecias before it is “safe” to transplant the hair into the affected area. Hair transplantation is successful and possible in many cases, except when the skin may be affected with a condition that would reject the transplant, such as alopecia areata, or when there is insufficient or non-existent donor hair, such as in the medical condition called alopecia universalis, which occurs when complete hair loss on the body manifests including the eyebrows and eyelashes. This condition is different from the total hair loss that follows chemotherapy. In alopecia universalis the return of hair growth is unpredictable, while patients who lose their hair after undergoing chemotherapy are most likely to re-grow their hair and do not require a hair transplant.
Figure 1.3: These illustrations show the various regions of the hair-bearing scalp that would be rebuilt with hair transplant differently regarding angles, direction, graft sizes, etc. These regional-scalp terms are referenced throughout the text and are shown in this schematic for better understanding of where they are located on the head and how they are related to one other.
The most familiar type of hair loss is called baldness and it is the state of lacking hair where it often grows, especially on the head. The most common form of baldness is a progressive hair thinning condition called androgenic alopecia that occurs in men and women. The degree and patterns of baldness can vary greatly depending on gender, age, genetics and sometimes on one's medical condition. The most common areas of hair loss in men are frontal, temporal and vertex, while the most commonly affected areas in women are behind the hairline and the top of the scalp and occasionally a receded hairline and/or vertex. The hair in the back of the head is rarely affected by thinning and serves as the donor area for hair transplantation. However, in some situations of female diffuse hair loss, the occipital areas could be affected, which robs those individuals of the possibility for a hair transplant (Fig. 1.3).
It was previously believed that baldness was inherited from the maternal side only. However, it is now generally accepted that both parents contribute to their offspring's likelihood of hair loss. Although baldness is not as common in women as in men, the psychological effects of hair loss, such as altering one's self-image and self-esteem, tend to be much greater in women than men.
Androgenetic alopecia (AGA) is also known as male-pattern baldness and is the most common cause of hair loss. Approximately 50% of men are affected by the age of 50 and thinning of the hair can begin as early as the age of 12 and as late as 45. Although the condition is benign, the psycho-social ramifications of AGA can be significant. A major determinant of AGA concerns androgen metabolism, more specifically the enzymes 5-alpha reductase and aromatase as well as androgen receptor proteins.
The 5-alpha reductase isoenzymes (type I and II) convert testosterone (T) to dihydrotestosterone (DHT). Both types of 5-alpha reductase are increased in the frontal-balding follicles compared with the non-balding follicles in the back of the head demonstrating that these isoenzymes contribute to AGA. DHT levels are also increased in the balding scalp compared with the non-balding scalp. Furthermore, women have 3 to 3.5 times less 5-alpha reductase than men, which probably accounts for why female AGA is less severe in most cases than with male AGA. Interestingly, individuals born without 5-alpha reductase type II do not develop AGA.
Aromatase is an enzyme that is part of the normal androgen metabolism that may have protective effects on AGA. Aromatase converts testosterone into estradiol and estrone and thereby results in less conversion of T into DHT. Aromatase is found in much higher levels in female scalps with six times in the frontal scalp and four times in the occipital scalp than in men. This may explain why women who suffer from AGA may still be able to preserve their frontal hairline.
Androgen receptor proteins (ARP) are found in the outer-root sheaths and in the dermal-papilla cells of the scalp follicles. ARPs are found to be 30% higher in the frontal-balding scalp than in the non-balding occipital follicles, while 40% lower in women than in men. ARPs are responsible for the signal transduction in the hair follicle that promotes the conversion of a thick, strong terminal hair into a miniaturized, fine hair. Interestingly, ARPs have the opposite effect in the beard and mustache, promoting thicker follicles in these areas at puberty.
Hair follicles produce both thick, terminal hair and fine, vellus hair. Vellus hairs develop on most of the human body from childhood regardless of sex. At puberty vellus hairs are replaced by terminal hairs in certain areas of the body, such as the axilla, pubis and face; and this change occurs by the influence of androgenic hormones. The differentiation between vellus and terminal hair is in their size and length, i.e., the hairs that grow thinner than 0.03 mm in diameter and shorter than 1 cm in length are considered vellus while hairs that exceed the parameters mentioned above are considered terminal hairs.
One of the hallmarks of androgenetic alopecia is the conversion of thick terminal hairs into miniaturized, vellus-like hairs. This process of miniaturization (i.e., shrinking of hair volume and growth length) is usually an indication that one is undergoing hair loss. The main mechanism for miniaturization relates to the shortening of the anagen phase, i.e., the hair becomes “lazy” and does not grow to its full term.
Many classification schemes exist to define types and extent of baldness. The most widely accepted standard is the Norwood classification for male-pattern baldness that was based on a study of one thousand adult men with male-pattern hair loss classified by the type of hair loss and age of onset. Some of the findings were as follows:
- The patterns with least hair loss (Type I and II) are most frequently found in men aged 18 to 40 years.
- The “monk's tonsure” Norwood-Hamilton Type III pattern becomes more common as men age and oftentimes could be combined with recession of the hairline.
- Type VII, the most severe pattern of hair loss, occurred in no men under age 30 in the Norwood study and became more prevalent in men older than age 60.
- Typically, AGA occurs early in most cases between the age group of 15 and 25 with lifetime progression. Most oftentimes, the clinical course is a gradual one with periodic episodes of increased hair loss. Maximum pattern is usually attained by one's forties, with ongoing thinning occuring throughout the remainder of one's life (Fig. 1.4).
All patterns of male-pattern hair loss tend to progress in stages and increase in prevalence with the age of the man. However, family history of male-pattern hair loss may be helpful in estimating probabilities for your future hair loss but cannot be predictive with complete accuracy.
While hair loss in men is often a genetic condition thus a lifelong process, it is unclear what predisposes a female toward hair loss. Some females may start exhibiting hair loss as early as after puberty, while others have no signs of any unusual hair shedding until later in life when they enter menopause. In women as in men, the most likely cause of scalp hair loss is androgenetic alopecia: an inherited sensitivity to the effects of androgens (male hormones) on the hair follicles of the scalp.
Figure 1.4: The Norwood or Norwood-Hamilton Scale grades degrees of male-pattern baldness. Type I shows minimal to no hair loss along the fronto-temporal expanse. Type II exhibits both fronto-temporal recession that does not extend further than a line drawn through a coronal plane 2 cm anterior to the external auditory canal. Type III hair loss refers to fronto-temporal recession that extends posterior to the coronal plane that lies 2 cm anterior to the external auditory canal. Type III Vertex indicates hair loss that primarily affects the vertex (or crown) region with or without accompanying fronto-temporal recession that does not exceed, as described in type III. Type IV reveals greater fronto-temporal loss than exhibited in type III along with marked hair loss in the crown area but with a moderately dense swath of hair that bridges the intervening expanse between the two areas. Type V hair loss shows more extensive alopecia in both the fronto-temporal and vertex areas with only a small bridge of dense hair between the two areas that remains. Type VI hair loss reveals a complete absence of any remaining hair that separates the two now confluent areas of alopecia. In addition, the hair loss is more extensive laterally and posteriorly. Type VII represents the most severe expression of male-pattern baldness with only a narrow-horseshoe configuration that remains along the posterior and lateral border of the hairline. Norwood also classified a variant of hair loss that afflicts approximately 3% of male patients with alopecia in which the fronto-temporal recession marches progressively posteriorly in a uniform fashion without a central, anterior peninsula of hair. Type IIA refers to a condition in which the entire anterior hairline is receded uniformly across the forehead but does not extend any further posteriorly than 2 cm anterior to the mid-coronal line. Type IIIA reveals alopecia that extends to the mid-coronal line. Type IVA signifies alopecia that has extended past the mid-coronal line. Finally, Type VA indicates significant recession of the hairline into the vertex, and severer forms of this variant become indistinguishable with Types V and VI.
Women with hair loss due to androgenetic alopecia tend to have miniaturizing hairs of variable diameter over all affected areas of the scalp. While miniaturizing hairs are a feature of androgenetic alopecia, miniaturization may also be associated with other causes and is not in itself a diagnostic mark of androgenetic alopecia. In postmenopausal women, hair may begin to miniaturize over the entire head, thereby losing its original volume and becoming difficult to style.
Although in some cases genetics can be the causative factor, health issues such as iron deficiency or hormonal imbalance that arises from pregnancy, menopause, withdrawal of oral contraceptives or hysterectomy can also spur hair loss in women (telogen effluvium). Pregnancy can lead to a prolonged estrogen-rich state in which hairs remain in the anagen phase until delivery. Following this, the hair is shed excessively for about four to twelve weeks afterward and most likely re-grows within three to six months. Besides these acute states of telogen eflluvium, women between 30 to 60 years of age are more likely to suffer an unexplained chronic telogen effluvium marked by recurrent hair shedding that does not lead to total baldness. It is important to note that female-pattern hair loss can begin as early as the late teens to early 20s in women who have experienced early puberty. If left untreated, this hair loss associated with early puberty can progress to more advanced hair loss. Hair loss in a woman (even when there is a family history of androgenetic alopecia) should never be assumed to be due to androgenetic alopecia. Examination and diagnosis by a physician, hair-restoration specialist is essential before any hair transplant is undertaken. Routinely, a battery of tests is suggested to female patients exhibiting hair loss, such as a full chemistry profile, sedimentation levels to check for inflammatory diseases, serum iron levels, male/female hormones [including testosterone and dehydroepiandrosterone sulfate (DHEAS)], and thyroid levels to check for proper function and scalp biopsy. For all of these reasons, hair loss in women can be more complicated than in men and should be more carefully explored for the cause so that a proper treatment plan can be instituted.
The most commonly used classification for female-pattern hair loss is the Ludwig Classification (Type 1 to 3). Alternatively, for women who suffer from male-pattern baldness, the Norwood-Hamilton classification can be used. The Ludwig classification emphasizes the diffuse nature of much female-pattern hair loss with frequently preserved hairline and thinning affecting the central top portion of the scalp, while the Norwood-Hamilton classification describes patterns of loss that are similar to male hair-loss patterns with affected hairline and/or thinning in the vertex area (Fig. 1.5).
Hair loss in women is different than in men because the areas affected can thin significantly but rarely become totally bare of hair.
Figure 1.5: This illustration shows the classification scheme for female pattern baldness as defined by Ludwig. Thinning tends to be more generalized than in male-pattern baldness.
There are various patterns of hair loss in women, and the following are the most common types:
- A “Christmas tree” pattern of diffuse hair loss, with the “base” of the “tree” at the hairline and the “tip” of the “tree” at the center of the scalp. There are two problems with this type of hair loss: the first is the inability to style hair to cover the thin area because the thinnest area is central and the person has to part her hair on the side and comb it over the thin area, and the second is the inability to wear bangs since the hairline is sparse. This type is the most prevalent type of female hair loss (Fig. 1.6A).
- A “Diffuse” pattern of hair loss that expands throughout the top scalp. Some studies have indicated that a diffuse thinning of hair is experienced to some degree by a majority of premenopausal women and by a large majority of postmenopausal women. There is a visible pattern of thinning that affects the top scalp and often the temporal areas as well. The most common feature for female alopecia is that the involved areas reach a certain point of decreased density but seldom become bare as seen in male-pattern hair loss (Fig. 1.6B).
- A type of “Male-pattern baldness” with preserved mid-frontal forelock (central) density. The regular female-shaped hairline is affected by the loss in both fronto-temporal corners (i.e., fronto-temporal triangles). The bald areas have triangular shapes that resemble the male-pattern hair loss of Norwood-Hamilton Types I to III (Fig. 1.6C).
It is important to mention that there is one more “model” of hair loss found in women (and rarely in men) called diffuse unpatterned alopecia (DUPA). This type of hair loss exhibits hair thinning throughout the entire scalp, oftentimes combined with global miniaturization, depriving these individuals from ever being candidates for hair transplant.
Figure 1.6A: This individual shows a Ludwig type of diffuse female-patterned hair loss. The hairline can be spared or affected with this type of loss. In this case, the individual demonstrates preservation of the hairline.
Figure 1.6B: This woman demonstrates a Christmas tree pattern of hair loss described by Elise Olsen in which the base of the tree is noted anteriorly and the top of the tree is situated toward the crown. The Christmas tree pattern is most easily revealed with the patient looking downward with the hair parted in the midline.
Figure 1.6C: This postmenopausal woman shows fronto-temporal recession similar to the type of hair loss experienced in male-pattern baldness.
About Hair Restoration
History of Hair Restoration
Surgical hair restoration began with the creative efforts of the pioneering Prussian surgeon and scientist, Johann Dieffenbach, in the early nineteenth century. He specialized in skin transplantation and cosmetic surgery, and was very inventive and ingenious in his surgical endeavors. The modern technique of hair transplantation began with interesting efforts of the Japanese surgeons Okuda in 1939 and Tamura in 1943 who transplanted hair in the pubic region. The common use of public bathing made hair loss in the pubic area culturally shameful and thus the interest to replant it. Although other Japanese surgeons worked to replace the damaged areas of eyebrows, they did not attempt to treat baldness per se. Their efforts did not receive worldwide attention at the time, and the traumas of the Second World War delayed the advancement in the field for another two decades.
The modern era of hair transplantation in the Western world was ushered in the late 1950s when New York dermatologist Norman Orentreich began to experiment with free donor grafts to balding areas of patients who experienced baldness. Medical grafting is a procedure similar to organ transplant, where a piece of tissue, i.e., graft, is transplanted from one area to another of the human body. It was originally believed that hair transplanted from the hair-bearing region, i.e., the donor site, into a balding region, i.e., the recipient site, would not thrive more than the original hair did in that region. However, Dr. Orentreich demonstrated that transplanted/new hairs grew and lasted as they did in their original home. This meant that the characteristics of the hair were preserved regardless of where they were transplanted, and this phenomenon is known as donor dominance. Otherwise if the recipient area were dominant, the site of transplantation would override the characteristics of the donor hair and cause it to fall out. This was a major discovery that created the foundation of modern hair-transplant surgery and allowed its development into a mature discipline that it is today. Although his method is synonymous with unsightly “plugs”, the philosophy behind Dr. Orentreich's approach is the foundation of current hair-restoration surgery.
For the next twenty years, surgeons worked on transplanting smaller grafts; and we have witnessed a tremendous evolution in hair-restoration techniques from cornrow plugs through to one-hair micro grafts, now to follicular-unit grafts.
Basic Principles and the Evolution of Hair-Transplant Surgery
Initially transplanted grafts were 2- to 4-mm round plugs that were punched out from the donor area, then the bald scalp was punched out and removed from the recipient area and the “holes” on the top of the head were plugged with punched grafts from the back of the head. This procedure created a doll's head-like result and left a shotgun-riddled donor area. Although considered as a progressive and successful procedure at the time, two major downsides existed for this procedure: The donor area was rapidly depleted leaving patients “unfinished” in attempt to cover their bald spots, and the transplanted hair was extremely unnatural. Transplanted plugs were placed far apart and straight up (instead of angled to mimic the natural hair angle), which created unsightly looking doll's-hair results.
In the attempt to yield more natural results, surgeons worked on making hair grafts smaller thus arriving at micro grafts, tiny pieces of scalp containing only 1 to 2 hairs. This technique was popularized in the 1980s. Although micro grafting gave more natural looking results, the chief complaint was the lack of density and “see-through” looking results. Further development in the field arose in 1984 with the discovery by Dr. Headington of follicular units or hair groupings. He described that hair grows in discrete bundles of 1 to 4 hairs instead of single hairs as previously believed (Fig. 1.7). Considering that hairs within the same follicular unit share a common sebaceous gland along with nerve and blood supply, their survival seems better if hairs within the unit are left together (instead of separated). Thus, the shift from micro transplant to follicular-unit transplant began. The discovery of follicular units did not only allow the recreation of more naturally looking patterns but also the creation of greater density within one session of hair transplantation.
The progress in the area of donor harvesting continued over the years.
Figure 1.7: In the 1980s, Headington discovered that hairs on the scalp do not grow singly but in groupings that have come to be known as “follicular units.” A follicular unit comprises groups of 1 to 4 hairs that grow in clusters spaced a short distance away from a neighboring follicular-unit cluster.
There were two areas of focus for improvement: preserving donor supply and enhancing donor appearance. The progressive nature of hair loss required the physician to anticipate future needs and to plan donor harvest accordingly. Regarding the appearance, every time a surgical procedure is performed, the donor area is left with a higher incidence of scarring. In the original punch donor harvesting after the hair was punched out, the open spaces were left to heal by themselves. Since this technique left significant donor scars behind, the next steps in evolution were in order: first to stitch the open “holes,” then to cut out and connect the “holes” and suture them in one straight line. The improvement in the appearance of the donor area with the suturing technique was remarkable. Combining micro grafting with the improvement in donor harvesting, physicians then transitioned to linear strip harvesting. This technique is still widely used in hair transplantation and is featured in this book as our preferred method.
As the progressive nature of hair loss creates the need for repeated surgeries, sometimes the donor area is left with many unsightly scars. The drawback of multiple donor harvesting over time is in the increased chances of creating wide scars as tension on the wound edges, which becomes greater with each subsequent harvest. Thus further refinement of the technique required better donor management. Consequently, two distinct approaches were pioneered. First, the Follicular-Unit Extraction (FUE) technique was developed in order to avoid strip harvest and circumvent a linear scar. Second, surgeons who preferred strip harvesting adopted a new suturing technique (the trichophytic closure) that allowed hair to grow through the scar and thereby camouflage its linear appearance.
Today there are a bewildering number of medical options for hair loss. Unfortunately, many of the herbal and vitamin hair-loss therapies lack substantiated evidence of benefit. With the advent of the Internet, numerous sites claim to have the product that can achieve instant hair growth and an enduring fix for baldness. Nevertheless, the Food and Drug Administration (FDA) has approved only two medical therapies for hair loss that have proven to be beneficial in selected patients, oral finasteride (marketed as Propecia by Merck) and topical minoxidil (marketed as Rogaine by Pfizer, now owned by Johnson and Johnson). Finasteride and minoxidil are approved for male hair loss, whereas only minoxidil is approved for female hair loss. Although these products may not be suitable for every person, they do provide a method to reduce or delay further hair loss and in some persons restore some hair fullness. In addition, these medications can also help to optimize the results of surgical hair restoration.
The effects of minoxidil on hair growth were discovered on the sidelines of another treatment. Originally used as a medication to treat severe hypertension, individuals who received minoxidil observed hair growth not only on their scalp but also on their body. Further investigation was conducted aiming to localize the hair-growing effects of minoxidil to the scalp only, leading to the development of the topical solution. Although, the initial early reports of oral minoxidil for hypertension linked minoxidil to increasing the risk in heart-disease patients, localized topical minoxidil for hair loss is safe and is an over-the-counter treatment in the United States.
Minoxidil is currently manufactured as a 5% and 2% concentration topical solution intended for direct application to the scalp (not the hair). The 5% concentration is designed for male patients, whereas the 2% concentration is designated for women. However, women who desire a more vigorous treatment can take the 5% concentration as an off-label indication. Interestingly, although the 5% concentration in women can show an increased rate of hair growth early on, there is no statistically significant difference in results between the 5% and 2% concentration after one year of usage.
The mechanism of action for topical minoxidil is unclear. As a potassium channel agonist, the cellular effects on hair growth are only speculative. However, it is known that minoxidil can cycle hairs out of telogen (the resting phase of the hair cycle) and push them into the anagen growth phase and also leads to a more sustained anagen period. Consequently, many individuals will experience increased hair shedding early on in treatment for several weeks and should be advised that this phenomenon actually indicates positive effect of the treatment, as hairs move from telogen to anagen. Considering the length of each hair-growth cycle, it takes approximately six months for new hair to re-grow long enough in order for the person to realize the effectiveness of the treatment. Also, because of this effect that minoxidil has on migrating hairs from telogen to anagen, minoxidil is a recommended treatment for individuals who suffer from acute or chronic telogen effluvium.
The main side effect of minoxidil is an allergic contact dermatitis, which causes a flaky and itchy scalp and accounts for one of the two major objections for use of minoxidil. Another side effect can be heart palpitations and/or increased growth of facial hair (seen mostly in women). The most common brand name for minoxidil is Rogaine. Minoxidil is available in generic form and can be purchased in most pharmacies throughout the world.
Beside side effects, another major reason for the lack of compliance to the product is the complaint about minoxidil making one's hair look oily. Not only does oily hair lack neatness but also it is difficult to style and sticks together, further exposing thin areas. Interestingly, some individuals will complain to the contrary, wherein the product renders their hair looking and feeling dry and in some situations leaves behind an unattractive white film. These complaints were mostly resolved with the release of Rogaine-brand foam.
The original minoxidil formula found in the lotion contains the alcohol-based ingredient propylene glycol, the culprit for scalp irritation and oily-looking hair, which when removed from the 5% Rogaine foam made the product both water-soluble and more tolerable. The correct application of the product is twice a day. However, once-a-day application may be beneficial considering that the product has been thought to last for 22 hours in the scalp when applied topically as compared with a 4-hour half life in the bloodstream when used as an intravenous preparation for hypertension.
The hair growing effects of finasteride were also discovered accidentally when the finasteride 5-mg pill (marketed as Proscar by Merck) was given to patients to manage an enlarged prostate. Subsequent studies found that a 1-mg dosage, which is marketed as Propecia, was adequate to combat alopecia. Finasteride is a prescription-only medication and at the time of publication of this textbook, it is still on patent by Merck so a generic version does not exist. Finasteride works as a type II 5-alpha reductase inhibitor, where 5-alpha reductase is the enzyme responsible for converting testosterone (T) to dihydrotestosterone (DHT). The presence of circulating DHT impacts hair follicles susceptible to hair loss and therefore a lower level of serum DHT can slow progression of hair loss and reconvert vellus hairs back into terminal hairs. The type II 5-alpha reductase is found predominantly in the hair follicles (and the prostate) and therefore does not promote hair growth anywhere else on the body.
Side effects occur in less than 2% of the patients and include decreased libido, erectile dysfunction, decreased ejaculate volume, and breast engorgement and tenderness. Side effects should fade away within six months after cessation and are found to be resolved in 58% of individuals who continue the treatment. Finasteride is known to reduce serum Prostate-Specific Antigen (PSA) levels by 30% to 50%. Therefore, individuals over 40 years of age who are taking finasteride should be informed about their altered PSA value and are advised to make certain that their primary-care physician is consulted. Finasteride has been shown to cause potential anatomical abnormalities (hypospadias) in a male fetus in women of childbearing age who take it but not in men who father children and who are on the medication. Therefore, finasteride is absolutely contraindicated in premenopausal women and has shown only equivocal benefit in those who are postmenopausal. In several controlled studies in postmenopausal women, finasteride was shown to have no benefit,1,2 whereas one more recent uncontrolled study indicated that there might be some gain in postmenopausal women who take finasteride.3 Although finasteride does not cause abnormalities in the fetus when men ingest it, decreased sperm count and semen volume, which may rarely occur, can diminish their fertility. Therefore, men who have difficulties conceiving may consider stopping finasteride during attempts at conception. Trials conducted in 2005 in the field of prostate-cancer prevention initially concluded that the use of finasteride increased the prevalence of prostate cancer. Additional trials conducted in 2008 rectified the original finding: since finasteride shrinks the prostate, it does not cause prostate cancer but facilitates earlier detection of cancer. Finasteride was once banned in sports because of its potential as a steroid-masking agent but recently has been approved for use in the olympics, FIFA and many other sports. Another medication used to treat enlarged prostate is dutasteride (Avodart by Glaxo Smith Kline), which is a potent inhibitor of both Type I and Type II isoenzymes of 5-alpha-reductase. This medication is not FDA- approved for hair loss, and its use is considered experiential and off-label. Nevertheless, discussions about the medication should be relegated to the physician's judgment with this commentary intended for the reader's education only.
Initial FDA trials in the late 1990s focused almost entirely on the benefits that finasteride and minoxidil have on the vertex, also referred to as the crown, region.4 However, subsequent studies have shown both medications to be proven beneficial in the frontal, temporal and midscalp hair. Therefore, individuals who claim that finasteride and minoxidil are only intended for restoration of the crown region are referencing outdated information.* Unfortunately, all the benefits from using these products would fade away with cessation of the medication. As it takes approximately six months to develop a visible effect from the medication, it usually requires about the same time for hair to reverse to its starting point once the individual stops medical treatment. Taking both medications has shown to have a synergistic benefit for the individual and when an individual decides to stop one medication, the benefits gained from the single product will disappear but the improvement attained from the other product will be maintained for as long as the individual continues on with that product.
Although finasteride and minoxidil can provide wonderful results, they are not a replacement for hair transplantation. As standalone treatments, finasteride and minoxidil can convert many wispy, vellus hairs back into thicker, terminal hairs (but not universally or uniformly so). However, for those individuals who have lost all of their hairs including vellus hairs (so-called slick baldness), neither finasteride nor minoxidil will prove to be beneficial. Nevertheless, even in relatively advanced stages of hair loss, finasteride and minoxidil may retard further hair loss even if no hair is actually restored in the regions of slick baldness. There are three observable effects of medical treatment: preserving the status quo (hair is maintained and the progression of hair loss diminished), increasing hair volume (fine, vellus hairs are reverted into thicker, terminal hairs, which in turn provides better coverage and better styling options), and increasing hair count (with fewer hairs going into telogen stage, there are fewer hairs falling out).
*The reason that the package inserts for both medications still only assert a benefit in the crown region reflects the extent to which FDA trials were conducted and therefore to which is permitted by law to declare.
As established, finasteride and minoxidil do not entirely restore a full head of hair, but they can contribute to a better aesthetic result when combined with hair transplant. Initially, they can help immediately after the surgery to protect original hair from going into postoperative shock and shedding and possibly to accelerate re-growth of the transplanted hair. Finasteride can be taken without interruption, while it is recommended to stop minoxidil two to seven days before and after the procedure. Ongoing use of the products is of course beneficial and recommended. Whether medications actually cause an increase in hair volume by the conversion of vellus hair into terminal hair or by re-growing or maintaining vellus hair, which would serve to camouflage the scalp, these products can undoubtedly enhance any hair-transplant result. Besides creating a better visual result, medical management will also help retard further hair loss and lengthen the time interval necessary for the next hair-transplant session.
In the process of hair thinning, decreased volume of hair no longer provides sufficient canopy to camouflage the naked scalp. As the light passes through the hair and reflects upon the scalp, an individual experiences bothersome “see-through” effect. The bigger the color contrast between the scalp tone and hair color, the more exposed the scalp appears and the more obvious thinning becomes. Camouflaging agents are topical products applied to the hair or scalp to increase the visual density of the hair. When applied to hair, these products are usually hair-building fibers (such as keratin protein or rayon fibers) that cling to the hair, creating a web-like coverage. Although these fibers can be affixed to the hair more tenaciously with additional hair sprays, a disadvantage of fibers is that they can come off onto pillows or clothes, causing social embarrassment and loss of effect. As people who have dandruff avoid wearing dark clothes, people using hair-thickening fibers should avoid wearing light-color clothing. In addition, these products can be slightly messy during application. Because camouflaging agents intertwine with an individual's own hair, these fibers should resist light rain but can be displaced with a heavy downpour or worse during swimming. Examples of camouflaging products include Toppik, Hair Magic, ProThik, and Fullmore. Another category of camouflaging product is applied directly to the scalp as a cream or lotion with the benefit that they are more resistant to washing out. The downside to the use of this kind of product is that they are more difficult to apply in a long hairstyle. Examples of this kind of product are DermMatch and COUVRe. In general, these agents are matched to the color of the individual's hair.
Camouflaging products are used principally for two reasons: independently to cover existing baldness and/or in combination with a hair transplant. The first reason is obvious, the individuals are bothered by hair loss but they are not interested in any surgical procedure. Alternatively, when combined with hair transplantation, camouflaging products can be offered as a temporary solution before or after surgery. If an individual has to wait to undergo hair-transplant surgery, these products can ease one's discomfort in dealing with his or her thin hair before surgery. In addition, they can be used in the postoperative setting when the patient experiences disturbing and unacceptable postoperative thinning (telogen effluvium) or during the transition period in anticipation for transplanted hair to grow.
It is important to mention that camouflaging products can accumulate and clog the scalp; hence, proper scalp hygiene should be addressed with every patient. For that reason, it is not recommended to use camouflaging products right after the surgery while scabs are still present. Furthermore, if a person is using minoxidil and camouflaging products simultaneously, it is important to stress the application of minoxidil on a clean scalp first. Therefore, the individual is instructed to apply minoxidil first and then the other products, in the morning, and for the evening application of minoxidil, to wash or wipe off any residual camouflaging product before minoxidil application.
Another way to camouflage baldness includes hairpieces and wigs. Hairpieces refer to partial hair prostheses, which are also known as hair systems or toupees, whereas a wig refers to a product that covers the entire expanse of the head. A cap is the term used to refer to a wig used by a male wearer, i.e., the product also covers the entire expanse of the scalp like a wig leaving no exposed natural hair. Most men wear hair systems as compared to caps. Although more people opt for surgical hair transplantation today making hairpieces not as popular as they were in the past, it is still important for the hair-transplant team to be educated about all hair-restoration options.
The three major complaints against hairpieces in the past were that the hair looked unnatural, that the hairpieces were too thick and bushy, and that the “hairline” was artificial in appearance and thus could not be exposed. Great strides have been made toward more natural-looking hairpieces in the last few decades. Additionally, no matter how natural a hairpiece may appear, the wearer is always worried that he may be “found out” and must limit certain activities like swimming, driving in a convertible car, or being around other people while grooming. Today's hairpieces are constructed of natural hair; their density and color can be matched very closely to the wearer's natural hair, and the base to which the hair is woven is thin and transparent allowing for an undetectable hairline. Hairpieces can be attached to the scalp through a variety of mechanisms. Tape adhesives are used for daily adherence so that the hair system can be easily removed at nighttime. Glue adhesives provide more durable bonding and oftentimes can keep a system in place for approximately more than a month's time. Similarly, hair weaving uses existing hair to provide anchorage to the hair system through inter-weaving of the two together. Weaving can also provide a month of time for a hair system to remain in place before maintenance is required.
Hairstyling and maintenance for a hairpiece requires special sensitivity and technique to provide proper adhesion and blending and is usually carried out in specialized salons. Women who wear wigs are usually well trained in hairstyling their wig, and wigs require less professional assistance for maintenance than a hairpiece does.
The benefit of a hairpiece and a wig is that they can provide immediate gratification as opposed to a hair transplant that requires six months or beyond to see the result and that may require several sessions to attain the desired level of hair density. Further, in individuals with extensive baldness (Norwood VII) or poor donor hair density, a hairpiece may be the only method to attain desirable levels of coverage and hair density. In addition, someone can undergo one or several hair transplantations while wearing a hairpiece or a wig and thereby have an inconspicuous transition from baldness to having one's hair restored to complete satisfaction.
- Roberts J, Price VH, Olsen E,et al. The effects of finasteride on post-menopausal women with androgenetic alopecia. In: Hair Workshop. Brussels, Belgium; 1998.
- Price VH, Roberts JL, Hordinsky M,et al. Lack of efficacy of finasteride in postmenopausal women with androgenetic alopecia. J Am Acad Dermatol. 2000; 43(5 pt 1):768–76.
- Iorizzo M, Vincenzi C, Voudouris S,et al. Finasteride treatment of female pattern hair loss. Arch Dermatol. 2006; 142(3):298–302.
- Kaufman KD, Olsen EA, Whiting D,et al. Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol. 1998; 39(4 Pt 1):578–89.