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Hair Loss Research

Hair Loss Research


Research and developments about hair loss, its causes, links to other health issues, and related topics.

Study Identifies A Possible Cause of Age-Induced Hair Loss

March 1st, 2016

Researchers show how the normal hair cycle (left) is disrupted by DNA damage (center),
resulting in age-induced hair follicle miniaturization (right)

We have known for decades that the incidence of male pattern baldness increases with age. New research published in the February 2016 edition of the journal Science has shed light on why this is the case. Researchers examining the role of hair follicle stem cells (HFSC) in the hair growth cycle have found that accumulated DNA damage in these cells results in the depletion of a key signaling protein and the progressive miniaturization of the hair follicle (and eventual hair loss).[1] The study represents a breakthrough in our understanding of the cell aging process and could open new pathways for the treatment of not only hair loss but other age-related conditions as well.

Background: The Hair Growth Cycle

At any point in time, a hair follicle exists in one of three phases:

      • Anagen Phase – this is the “growth” phase in which the hair follicle is actively producing living hair. Anagen can last from two to seven years.
      • Catagen Phase – this is a short transitional phase in which hair growth stops, the middle of the follicle constricts, and the bottom of the follicle begins to form the “club.” The follicle also separates from the bloodstream. Catagen lasts two to three weeks.
      • Telogen Phase – this is the “resting” phase in which the clubbed hair detaches from the dermal papilla and is susceptible to falling out. Telogen lasts three to four months before hair follicle stem cells initiate a new anagen (growth) phase and the cycle repeats.

Stem Cells and the Hair Cycle

Normally, hair follicle stem cells (HFSC) perpetuate the hair cycle by initiating a new anagen (growth) phase after the telogen (resting) phase. But HFSC, like all cells, age over time. Included in this aging process is damage to DNA strands inside these cells due to spontaneous errors in DNA replication or those due to exposure to sunlight and other insults. While it has been well understood that hair follicle miniaturization occurs as a person ages and that damage to genetic material contributes to the process, the exact mechanism that ties cell aging to the disruption of the normal hair cycle was unknown. The recent study examines miniaturization from cell aging and distinguishes it from miniaturization caused by the effects of DHT.

Results of the Study

The key finding in this new research is that as hair follicle stem cells (HFSC) accumulate genetic damage over time, their store of a signaling protein called COL17A1 is depleted. The depletion of this key protein forces HFSC to differentiate into a common type of skin cell called a keratinocyte. By differentiating into keratinocytes, the population of HFSC gradually shrinks, there are fewer HFSC to initiate the anagen (growth) phase, and the telogen (resting) phase is extended. With a gradually longer telogen phase and shorter anagen phase, the follicle progressively miniaturizes. Eventually, the hair-producing follicle disappears leaving a bald scalp and the keratinocytes, which no longer serve a purpose in the hair growth cycle, are ejected from the skin.1 Click here to view the graphic that illustrates this process.

The authors of the study suggest that restoring COL17A1 levels, or halting their depletion, may prevent this aging-induced hair follicle miniaturization from occurring.1

With perhaps much broader significance, the study confirms the tight linkage between the instability of genetic material in stem cells (that can be due to environmental factors) and the shrinkage and functional decline seen in many organs as they age.


Progressive hair loss is a pervasive problem for males as they age. However, current treatments deal, exclusively, with hormone-induced miniaturization. The discovery of the mechanism behind age-induced miniaturization may result in a new avenue for the treatment of hair loss. More research into methods of boosting levels, or preventing the depletion, of COL17A1 may yield a hair loss therapy that targets this cause of hair loss.

Further, developing a better understanding of the cell aging process may open up new avenues of research into the causes of, and potential solutions to, the age-induced decline of major organs in the body.

Read more:

Image c/o Science


      1. Matsumura H, Mohri Y, Binh NT, et al. Hair follicle aging is driven by transepidermal elimination of stem cells via COL17A1 proteolysis. Science. 2016 Feb: Vol. 351, Issue 6273, p. 613. []

Androgen Treatment May Boost Hair Regrowth in Women

August 3rd, 2015

A study published in the British Journal of Dermatology suggests that subcutaneous placement of testosterone pellets may boost hair regrowth in some women.[1]

This retrospective analysis examined patients who had androgen deficiency. Of the 285 patients studied, 76 had some degree of hair loss prior to beginning treatment. At one year on testosterone replacement 63% reported an increase in hair regrowth on the scalp.

Traditionally, elevated levels of androgens, such as testosterone, are felt to be the primary cause for common hair loss in both men and women. This is due to the seemingly adverse effect of androgens on hair follicles. This has held true for most men with patterned hair loss in whom DHT-blockers, such as Propecia (finasteride) and Avodart (dutasteride), have proven to be a potent remedy.

Given this, it was surprising that none of the 285 women in the study who had been treated with testosterone reported any hair loss after one year. In fact, of the 76 women who initially reported hair loss before the study, 63% reported positive hair regrowth at one year.

The researchers noted that patients with a “significantly higher body mass index (BMI)” were in the subset of those who did not regrow any hair. This suggests that a higher dose might be needed in some patients.[2],[3],[4]


By correlating higher levels of testosterone with more hair growth and/or retention in women, the study bolsters the idea that hair loss in men and women is caused by different mechanisms. Though not conclusive, the study opens the idea that testosterone implantation can effectively treat hair loss in women.


      1. Glaser RL, Dimitrakakis C, Messenger AG. Improvement in scalp hair growth in androgen-deficient women treated with testosterone: a questionnaire study. Br J Dermatol. 2012 Feb;166(2):274-8. []
      2. Kapp N1, Abitbol JL2, Mathé H2, Scherrer B2, Guillard H2, Gainer E2, Ulmann A2. Effect of body weight and BMI on the efficacy of levonorgestrel emergency contraception. Contraceotion. 2015 Feb;91(2):97-104. doi: 10.1016/j.contraception.2014.11.001. Epub 2014 Nov 8. []
      3. Lopez LM, Grimes DA, Chen M, Otterness C, Westhoff C, Edelman A, Helmerhorst FM. Hormonal contraceptives for contraception in overweight or obese women. Cochrane Database of Systematic Reviews 2013, Issue 4. Art. No.: CD008452. DOI: 10.1002/14651858.CD008452.pub3 []
      4. Glasier A, Cameron ST, Blithe D, Scherrer B, Mathe H, Levy D, Gainer E, Ulmann A. Can we identify women at risk of pregnancy despite using emergency contraception? Data from randomized trials of ulipristal acetate and levonorgestrel. Contraception. 2011 Oct;84(4):363-7. doi: 10.1016/j.contraception.2011.02.009. Epub 2011 Apr 2. []

Stem Cell Therapy Increases New Hair Growth in Males and Females with Genetic Hair Loss

June 3rd, 2015

According to a study[1] published in ePlasty (a peer-reviewed, open access medical journal), stem cell therapy has been found to increase new hair growth in both males and females who have androgenetic alopecia (genetic hair loss).

The Study

Researchers treated a group of male and female androgenetic alopecia patients with stem cells derived from fat tissue (called adipose-derived stem cells). Additionally, to see if finasteride would confer any additional benefit along with any possible benefit of stem cell treatment, the researchers gave finasteride to half of the male patients.

After the treatment, the researchers observed a significant growth of new hair in both male and female subjects, with no significant difference between males and females. Finasteride conferred no significant additional hair growth benefit to males also receiving stem cell therapy.

The researchers concluded that injections of stem cells into the scalp of alopecia patients appears to be an effective hair loss treatment and may represent a new avenue of therapy, especially for men who do not respond well to finasteride and for women who currently have limited medical treatment options.

While there was no significant difference in hair growth between those males treated with stem cells and finasteride and those treated with stem cells alone, the researchers plan to conduct more carefully designed studies in the future to better evaluate the benefit of combining these two therapies.


      1. Fukuoka H, Suga H. Hair Regeneration Treatment Using Adipose-Derived Stem Cell Conditioned Medium: Follow-up With Trichograms. EPlasty, March 26, 2015, 15:e10. []

New Research Identifies Hair Follicle Dermal Stem Cells as Playing a Role in Hair Growth

December 18th, 2014

Scientists have known that dermal papilla (DP) cells trigger hair follicle regeneration, a mechanism that protects hair follicles against injury, disease and aging. They have also known that hair loss is associated with the gradual depletion and atrophy of DP cells. But what they did not know is how DP cells were maintained inside healthy hair follicles.

New research has shown that the hair follicle dermal stem cell plays a direct role in maintaining these hair growth inducing DP cells.[1]

This discovery sets the stage for the development of new drugs designed to target these dermal stem cells in order to “replenish or rejuvenate the DP cells that are responsible for inducing hair growth,” says Jeff Biernaskie, PhD, one of the researchers.

Such drugs could be useful for repairing hair follicles damaged by disease or injury, or by medical treatments, specifically chemotherapy and/or radiation therapy. The development of such drugs, however, could be at least a decade or more out.


      1. Rahmani W., Abbasi S., Hagner A., Raharjo E., Kumar R., Hotta A., Magness S., Metzger D., Biernaskie J. (2014), Hair follicle dermal stem cells regenerate the dermal sheath, repopulate the dermal papilla, and modulate hair type. Dev Cell, Dec 8;31(50:543-58). []

Crown Balding and Heart Disease Linked in British Medical Journal Study

April 10th, 2013


A new meta-analysis of six studies, published in the British medical journal BMJ Open, has found a linkage between balding at the crown and coronary heart disease. While the top-line result of the study may be alarming, let us look first at some of the key facts.

      • While the study showed a modest link between crown balding and heart disease, the link was not as strong as for other heart disease indicators such as smoking, obesity, cholesterol levels and blood pressure.
      • There was no link established for men with a receding hair line.
      • Key indicators of heart disease — high blood pressure, high LDL cholesterol, and smoking — are present in about half of Americans, according to the Center for Disease Control in America. So this is a health issue faced by many Americans, hair loss or not.
      • Importantly, the most appropriate response if you have balding at the crown (and particularly crown balding at an early age), is not to worry first and foremost about your hair, but to concentrate on basic heart health and maintaining a healthy lifestyle. Discuss these issues and any concerns with your primary care physician.

Researchers at the University of Tokyo in Japan compiled information from six different studies with a combined total of almost 37,000 male participants. The studies were published between 1993 and 2008. Although one of the six studies did not find a link between baldness and coronary heart disease, the other five studies did find a link with the strength of the association differing in each study. In general, the more severe the balding at the crown, the more likely there was an association with heart disease. In addition, early onset of vertex balding — i.e. early balding at the crown — was found to be associated with the early development of more significant heart disease.

More research needs to be done to investigate the actual medical causes of the linkages shown.

An article on the BBC News website quotes a cardiac nurse from the British Heart Foundation discussing the findings:

“Although these findings are interesting, men who’ve lost their hair should not be alarmed by this analysis. Much more research is needed to confirm any link between male pattern baldness and an increased risk of coronary heart disease. In the meantime, it’s more important to pay attention to your waistline than your hairline.”

Image c/o BBC online




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Tags:  Balding, Balding at the Crown, BBC News, BMJ Open, Center for Disease Control (CDC), Coronary Heart Disease, Crown, Early Hair Loss, Early Hair Loss & Heart Disease, Extensive Baldness, Japan, Medical Research, Rogaine (Minoxidil), Vertex

Early Baldness May Suggest Prostate Cancer Risk

March 28th, 2013

A study of Australian men between the ages of 40 and 69 suggests that men who were mostly bald by the age of 40 were more likely to develop prostate cancer in their 50s or 60s. The Melbourne Collaborative Cohort study of about 10,000 men showed that men who have high levels of testosterone may be more vulnerable to cancerous prostate tumors.

The team of scientists that conducted the long-term study, which was published in the journal Cancer Epidemiology, Biomarkers and Prevention, reported that both baldness and prostate cancer are age-related and androgen dependent conditions, so these findings are not surprising. The statement said, “We found that baldness at the age of 40 might be a marker of increased risk of prostate cancer.”




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Tags:  Androgens, Early Hair Loss, Early Hair Loss & Prostate Cancer, Hair Loss Age, Male Pattern Baldness, Medical Research, Prostate Cancer, Testosterone

Research Points To Vitamin D Receptors As Possible Clue To Reversing Hair Loss

September 13th, 2012

Could it be that Vitamin D is the cure for baldness that scientists have been looking for all these years? New research on Vitamin D, and its receptors in hair follicles, has taken us down a previously untrodden path that could, potentially, lead to new medical treatments for hair loss.

The Vitamin D receptor was previously known to stimulate hair follicles, which were in the dormant phase of hair growth, to grow hair when activated. The research into Vitamin D and its effect on hair and skin, centers around this receptor.

One group of researchers — based in San Francisco, California — has discovered that a molecule, called MED, suppresses the Vitamin D receptor, thereby preventing the follicle from growing a new hair. Their research in mice found that blocking the MED molecule allowed mice to grow more hair. A second research team, from Harvard Medical School, has found a molecule that activates the receptor. However, they have been unable to use the molecule to grow new hair.

A third research group, based in Japan, used Vitamin D to stimulate stem cells to become hair-producing follicles in rats. Dr. Kotaro Yoshimura says of the study, “The results suggest that it may be useful in expanding human [dermal papilla cells (DPCs)] with good quality, and help establish a DPC transplantation therapy for growing hair.” His colleague on the study, Dr. Noriyuki Aoi, said, “We found that treating the dermal papilla cells with [Vitamin D] significantly enhanced the growth of new hair over that of the control group. We also observed a better rate of maturation of the follicles. In other words, the hair grew thicker and lasted longer.”

While the third group appears to be the closest to achieving hair growth from a Vitamin D-based treatment, viable treatments in humans are still many years away. As we have indicated in other posts on the Hair Transplant Blog, there is a great deal of ongoing medical research into the causes and treatment of hair loss. The way the field has progressed over the last 5 years it seems to be just a matter of when, not if, a cure for baldness is available to the public.

Read more about ongoing medical research on the causes of and treatments for hair loss




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Tags:  Baldness Cure, Cure for Baldness, Dermal Papilla, Dormant Phase of Hair Cycle, Hair Cloning Methods, Hair Follicles, Hair Growth, Hair Loss Cure, MED Suppresses Vitamin D Receptor, Medical Research, Medical Treatment of Hair Loss, Vitamin D, Vitamin D Receptors

Researchers “Accidentally” Reverse Hair Loss Caused by Stress

March 7th, 2011

Sometimes an “accident” in the laboratory can lead to a remarkable breakthrough. Penicillin, Botox, Viagra, and Minoxidil — the active ingredient in Rogaine — were all unintended discoveries that led to treatments for a variety of conditions.

A similar twist of fate, this time by researchers at UCLA, could lead scientists to a new hair loss treatment.

Mice had been bred to overproduce a stress hormone that causes them to lose their hair. The scientists’ intention was to study the effects of a chemical compound, called astressin-B, on blocking the effects of stress on the mouse colon.

What they saw, however, surprised them. The mice that were treated with the chemical had fully regrown their hair. After repeating the results, the researchers injected the chemical into young mice, which were similarly genetically altered but had yet to lose their hair. Those mice never lost their hair despite the fact that they, too, were bred to overproduce the stress hormone.

Whether this discovery will lead to a drug that cures common baldness in human beings, or whether such a cure will only affect hair loss due to stress, is unknown at this early stage.

For further reading on this discovery, see articles in Dermatology Times and the New York Times, as well as the primary scientific publication in the journal PLoS ONE.




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Tags:  Astressin-B, Causes of Hair Loss, Dermatology Times, Hair Loss Treatment, Medical Research, New York Times, PLoS ONE, Rogaine (Minoxidil), Stress

Research Points to Decreased “Progenitor” Stem Cells as Cause of Male Pattern Baldness

January 7th, 2011

Research published in the January 2011 issue of the Journal of Clinical Investigation (Vol. 121, issue 1) reveals another breakthrough in the medical community’s understanding of the causes of — and possible cure for — androgenetic alopecia, or common male pattern baldness. The new research shows that the presence of a certain type of cell, called progenitor cells, is significantly reduced in men with common baldness compared to men who are not bald.

An article on AOL, which calls these “faulty” stem cells the root of hair loss in men, sheds light on the findings:

Using cell samples from men having hair transplants, a team led by University of Pennsylvania dermatologist Dr. George Cotsarelis compared follicles from portions of bald scalp to follicles from scalp areas with hair.

They learned that on the same person, the bald patches had an equal number of stem cells as the patches with hair. But they did find a difference: the areas of bald scalp had a significantly lower number of a more mature type of cell, called a progenitor cell.

That finding suggests that stem cells in parts of the head without hair have malfunctioned, losing their ability to convert into progenitor cells.[1]

The study showed that, contrary to conventional wisdom, it is not the total “number” of stem cells that causes hair loss. In fact, the scientists’ original hypothesis was that, “the miniaturization of the hair follicle seen in [androgenetic alopecia] may result from loss of hair follicle stem cells.” That hypothesis turned out to be inaccurate. Instead, the authors of the study indicate that the findings:

…Support the notion that a defect in conversion of hair follicle stem cells to progenitor cells plays a role in the pathogenesis of [androgenetic alopecia].[2]

The study’s results suggest that further research into the mechanism for the conversion of hair follicle stem cells to progenitor cells is warranted. If scientists can devise a way to correct that mechanism, then, in theory, stem cells in men who are predisposed to have androgenetic alopecia can be converted to progenitor cells at a normal rate. That correction would, in theory, eliminate that person’s susceptibility to the hair follicle miniaturization which causes hair loss, and would effectively cure his male pattern baldness.

Progenitor Cells vs. Stem Cells

Compared to stem cells, progenitor cells are further along in the process of differentiating into their target tissue, in this case mature hair follicles. Whereas stem cells are pluripotent, meaning that they can differentiate into a number of types of cells, progenitor cells are already committed to a specific cell line. Another important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can only divide a limited number of times.

For further reading on this stem cells and the causes of hair loss, here are some links:


      1. AOL, “Scientists Trace Root of Male Hair Loss to Faulty Stem Cells,” January 5th 2011 []
      2. J Clin Invest. doi:10.1172/JCI44478. []




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Tags:  Androgenetic Alopecia, AOL, Dr. George Cotsarelis, Hair Follicle, Hair loss in Men, Hair Loss Treatment, Male Pattern Baldness, Medical Research, Miniaturization, Progenitor Cells in Hair Loss, Stem Cells

Update on the Cause and Medical Treatment of Patterned Hair Loss

Schweiger E, Boychenko O, Bernstein RM. Update on the pathogenesis, genetics and medical treatment of patterned hair loss. J of Drugs in Dermat 2010; 9(11): 1-8.

Synopsis: This publication reviews the major advances in the science of hair loss that have occurred over the past decade. These include advances in the diagnosis of androgenetic alopecia, advances in our understanding of the mechanisms behind genetic hair loss, studies in the efficacy of medical treatment of hereditary baldness, the development and FDA-approval of the lasercomb device for hair restoration, and the development of a screening test for hair loss.

Hair Casts or Pseudonits Acquired Following Psychological Trauma

Jonathan L. Held, MD, New York, NY
Robert M. Bernstein, MD, New York, NY

Cutis 1989; 43: 380-1.

We present an unusual case of hair casts occurring after psychological trauma. These pseudonits must be correctly differentiated from pediculosis capitis.

Hair casts (peripilar keratin casts), or pseudonits, are 2 to 7 mm long, discrete, firm, shiny, white, freely movable tubular accretions that encircle the hair shafts of the scalp. Cursory examination of the patient with these pseudonits may result in the erroneous diagnosis of pediculosis capitis.

Since their original description by Kligman in 1957, more than thirty cases of hair casts have been reported in the English language medical literature. Hair casts have been classified into parakeratotic (“secondary”) or nonparakeratotic (“idiopathic”) types. The former is more common and is related to a coexistent abnormality involving the scalp, such as psoriasis. The “idiopathic” hair cast, however, is not found in association with any disease of the scalp or any other hair shaft abnormality.

Light microscopic and ultrastructural studies of the nonparakeratotic hair casts demonstrate both inner and outer root sheath components and suggested an infrainfundibular origin. The exact mechanism of hair cast shedding has not, however, been elucidated.

We present an unusual case of hair casts that occurred following severe emotional trauma associated with the unexpected death of a patient’s parent. This observation suggests a possible causative basis similar to that of Beau’s lines of the nail plate.

Case Report

A 9-year-old white girl was referred by her school nurse for suspected pediculosis capitis. Initial observation revealed a healthy-appearing girl with shoulder-length hair containing small white specks all located approximately 3 mm from the scalp. The scalp appeared normal. Pulling the hair did not cause increased hair shedding. Alopecia was not present and regional hairs were all of similar length. Microscopic examination of plucked hair showed tubular accretions or pseudonits but true nits were not seen.

The patient denied any recent illness, but had been distraught over the untimely death of her father thirty days earlier. She was not taking any medication. Family members were unaffected. The hair casts were removed by acetic acid soaks followed by combing; they did not recur.


Hair casts may occur in association with parakeratotic scalp disease or as an idiopathic condition apparently unrelated to other scalp and hair shaft abnormalities. Our patient had no evidence of other dermatologic disease and was not taking any medication. The onset of her hair casts appears temporally related to the severe psychological stress caused by her father’s untimely death.

Nail plate and hair abnormalities are known to occur after severe systemic insults, including psychological disturbances. After such insult, matrix mitotic activity may slow, resulting in transverse depressions of the nail plate (Beau’s lines) or focal narrowing of the hair shaft (Pohl-Pincus marks). The overall growth rate and pattern remain normal.

It seems reasonable that a similar process, affecting the process of keratinization at or just below the pilar infundibulum, could result in the formation of hair casts. The hair casts would then proceed distally, with normal hair growth, at a relatively uniform pace.

As is often the case, hair casts may initially be misdiagnosed as the nits of pediculosis capitis. Reassurance and simple mechanical removal usually suffice as treatment. While the exact mechanism of hair cast formation remains to be determined, their apparent temporal relation to severe emotional trauma suggests a causative mechanism analogous to that responsible for Beau’s lines and Pohl-Pincus marks.


      1. Kohn SR; Hair casts or psuedonits. JAMA 238: 2058-2059, 1977.
      2. Kligman AM: Hair case: Parakeratotic comedones of the scalp. Arch Dermatol 75: 509-511, 1957.
      3. Taieb A, Surleve-Brazeilie JE, Maleville J: Hair casts. Arch Dermatol 121: 1009-1013, 1985.
      4. Keipert JA: Hair Casts: Review and suggestion regarding nomencla¬ture. Arch Dermatol 122: 927-930, 1986.
      5. Herman PS: Peripilar casts. Arch DennatolForsch 248: 321-327, 1974.
      6. Beau JHS: Note sur certains caractères de sémeiologie retrospective preserves par les ongles. Arch Gen Med 11: 447, 1846: cited by Weis-mann K: JHS Beau and his description of transverse depressions on nails. BrJ Dermatol VI: 571-572, 1977.
      7. Sims RT: “Beau’s lines” in hair. Br J Dermatol 79: 43, 1967.
      8. Stroud JD: Hair shaft defects. Cutis: 1375-1382, 1969.
      9. Colver GB, Dawber RPR: Multiple Beau’s lines due to dysmenorrhoea. Br J Dermatol 111-113, 1984.

Hair Casts or Pseudonits Acquired Following Psychological Trauma
 Robert M. Bernstein, M.D., Jonathan L. Held, M.D.
Cutis; 431-380

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