Bernstein Medical Center for Hair Restoration - Causes of Hair Loss

Causes of Hair Loss

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Huffington Post on Hair Loss Genetics

Dr. Bernstein contributed to an article on hair loss genetics published in Huffington Post. In the article, “Sorry, You Can’t Just Blame Your Mother’s Father for Your Thinning Hair” Dr. Bernstein addresses the common myth that hair loss is inherited exclusively from the mother’s side of the family – and, more specifically, from your mother’s father. While your mother’s (or maternal grandfather’s) genes can be the culprit, the characteristics of your hair are influenced by many different genes that may come from either or both sides of your family.

The confusion stems from the fact that men inherit their X chromosome from their mother and a key gene involved in hair loss is found on the X chromosome.

Dr. Bernstein explains:

The androgen receptor gene is an X-linked gene, so there’s a slightly greater incidence of it following the mother’s side of the family than the father’s side, but genetic hair loss is polygenetic and the expressivity is very variable, so both sides can contribute to someone’s hair loss.

Dr. Christopher Cunniff, a clinical geneticist at Weill Cornell Medicine and New York-Presbyterian Hospital, added a comment that the genes most clearly identified as having influence on hair texture or color have not been found to be located on the X chromosome.

The article discusses hair loss genetics and a range of factors affecting the characteristics of one’s hair.

Image c/o: Ruigsantos via Getty Images

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Q: Is it ill-advised to comb one’s hair more than twice a day, especially hair that has been transplanted? Will frequent combing induce hair loss? — G.K. ~ Paramus, N.J.

A: Combing or brushing one’s hair does not cause hair loss – no matter how many times a day you do it. However, constant traction with braids or hair extensions can cause hair loss and this loss can be permanent.

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Q: I have read several articles on the internet which suggest that resistance training can accelerate male pattern baldness. Is there any truth in this? –B.F., Altherton, CA

A: Anything that raises androgen levels in your body can potentially accelerate hair loss. That said, I suggest that you should exercise as you normally would. As long as you don’t take drugs to enhance your workout, the effects should be minimal.

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Since 1993, minoxidil has been the most successful topical treatment for hair loss in both men and women, yet its exact mechanism of action remains unknown.

A 2004 review of minoxidil’s possible mechanisms of action ((Messenger AG, Rundegren J. Minoxidil: mechanisms of action on hair growth. Br J Dermatol. 2004;150(2):186-94.)) suggests that the best evidence supports the idea that minoxidil causes hair follicles in the later phases of their resting phase (telogen) to shift prematurely into an active growth phase (anagen) sooner than they otherwise would; this causes a rapid increase in hair growth. They also found good evidence that minoxidil works to thicken the hair by increasing hair diameter.

While minoxidil’s effects on other critical factors known to affect hair growth — such as cell proliferation, collagen synthesis, vascular endothelial growth factor and prostaglandin synthesis — remain uncertain, more recent research has found evidence that it may also suppress the androgen-androgen receptor responsible for androgenetic alopecia. ((Hsu CL, Liu JS, Lin AC, Yang CH, Chung WH, Wu WG. Minoxidil may suppress androgen receptor-related functions. Oncotarget. 2014;5(8):2187-97.))

Understanding minoxidil’s exact mechanism of action remains today an important line of research both for the development of better hair loss treatments and for a better understanding of the biology of hair growth.

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Q: I have been using an increased dosage of Propecia now for around 8 months and Rogaine for about 6 months. I know that shedding can be expected for the first 3-6 months, but I believe I am now beyond that timeframe. Have you seen cases in which these products merely exacerbate hair loss without the expected regrowth? — N.E., Travilah, Maryland

A: It is a bit long to still see shedding, but from my experience, either the medications are working (and you are still in the shedding phase) or you are not responding to them. I have not seen minoxidil or finasteride worsen hair loss. My advice would be to continue the same course for at least a year before re-evaluating their use.

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Q: The last few months my friend and I experimented with andro gel thinking it would make our T levels go up and make our work outs better. We got the andro gel online with no prescription (which I know is really stupid on our behalf). The past couple of months I have been experienced a lot of acne and hair loss. I went to the doctor and confessed and said what I did, and he was very disappointed and lectured me on how dangerous it was and stupid on my behalf – which I totally agree. He told me the rise in testosterone from andro gel contributed to the acceleration of hair thinning and acne. I had mild hair loss prior but the andro gel seem to have accelerated it. The doctor put me on Propecia and gave me some acne cream for the acne. He said the Propecia will undo some of the damage it did for the hair. In your experience, can Propecia reverse some of the damage? I am 28 years old.

A: Your doctor is giving you the right course of action. Testosterone supplements can accelerate hair loss, particularly in those with underlying genetic hair loss. Finasteride 1mg (Propecia) should help you to grow your hair back. You may also want to consider using minoxidil (Rogaine) in addition.

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Miniaturized human hair follicle shows concentration of Prostaglandin D2 (in green). Credit: Garza and Cotsarelis/Penn Medicine)
Miniaturized human hair follicle shows concentration of Prostaglandin D2 (in green). Credit: Garza and Cotsarelis/Penn Medicine)

Researchers at the University of Pennsylvania, who were investigating the biological causes of androgenetic alopecia or common genetic hair loss, have discovered that levels of a certain inhibitor protein, called Prostaglandin D2 (PD2), are elevated in bald areas on the scalp. This discovery could be an important breakthrough in developing a medical hair loss treatment that regulates the production of the protein, or one that blocks it from attaching to its receptor protein.

Prostaglandins are a family of proteins that have a wide range of functions, including controlling cell growth and constricting and dilating muscle tissue. According to an article in ScienceDaily, the researchers had previously found evidence that something was inhibiting hair growth, but they did not expect to find prostaglandins involved in the miniaturization of hair follicles:

In men with androgenetic alopecia, Prostaglandin D2 was found to be three times higher in bald scalp tissue versus areas of the scalp with hair. Additionally, when hair follicles in a laboratory culture were treated with PD2, the hairs were significantly shorter than non-treated ones. A derivative of PD2, called 15-dPGJ2, was found to completely inhibit hair growth.

The receptor protein that is active with both prostaglandins, called GPR44, may hold the key to limiting the effects of PD2 and, therefore, in regulating hair loss in both men and women. While the study looked only at men, the GPR44 receptor protein exists in women as well. So, theoretically, a topical hair loss treatment may be developed that would prevent or limit thinning or hair loss in both sexes.

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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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Q: I have been on finasteride for about 7 months. After my latest haircut I can see that my scalp is shiny. I read that is from sebum buildup and it can cause a layer that clogs the growth of hair. I was wondering if this is true and, if so, how can it be treated? — T.C., Philadelphia, PA

A: It is not true. Hair loss is caused by the miniaturizing effects of DHT on the hair follicle, not by blocked pores.

For more on this topic, view our pages on the causes of hair loss in men or the causes of hair loss in women.

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Dr. Angela Christiano of Columbia University in New York and a team of scientific researchers have identified a new gene involved in hair growth. Their discovery may affect the direction of future research for hair loss and the diagnosis and ultimate prevention of male pattern baldness.

The condition which leads to thinning hair is called hereditary hypotrichosis simplex. Through the study of families in Pakistan and Italy who suffer from this condition, the team was able to identify a mutation of the APCDD1 gene located in chromosome 18. This chromosome has been linked to other causes of hair loss.

According to Dr. Christiano, “The identification of this gene underlying hereditary hypotrichosis simplex has afforded us an opportunity to gain insight into the process of hair follicle miniaturization, which is most commonly observed in male pattern hair loss or androgenetic alopecia.”

The mutation of the APCDD1 gene inhibits the Wnt signaling pathway. Although this recently discovered gene does not explain the complex process of male pattern baldness, the importance of this discovery lies in the Wnt signaling that the gene directs, has now been shown to control hair growth in humans, as well as in mice.

Reference: Nature 464, 1043-1047 (15 April 2010) | doi:10.1038/nature08875;

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Q: Why does a hair transplant grow – why doesn’t the transplanted hair fall out? — J.F., Redding, C.T.

A: Hair transplants work because hair removed from the permanent zone in the back and sides of the scalp continues to grow when transplanted to the balding area in the front or top of one’s head. The reason is that the genetic predisposition for hair to fall out resides in the hair follicle itself, rather than in the scalp — this idea is called Donor Dominance. This predisposition is an inherited sensitivity to the effects of DHT, which causes affected hair to decrease in diameter and in length and eventually disappear — a process called “miniaturization.” When DHT resistant hair from the back of the scalp is transplanted to the top, it will continue to be resistant to DHT in its new location and grow normally.

Read more about Miniaturization
Read about the Causes of Hair Loss in Men

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Q: Can stress accelerate hair loss? I am 25 and there is balding on my dad’s side of the family. I never had any thinning or hair loss till this year. I guess you can say I’ve been under a lot of stress. When I did notice shortly after my 25th birthday I started stressing even more, which led to more hair loss. It is thinner up front and it is thin on top. I have heard of some hair docs mapping your head for miniaturization, do you do this too? — E.W., Miami, FL

A: Yes. The presence of miniaturization (decreased hair diameter) in the areas of thinning allows us to distinguish between hair loss due to heredity (i.e. androgenetic alopecia) — in which hair progressively decreases in diameter under the influence of DHT — and other causes. The degree of miniaturization can be assessed using a hand-held instrument called a densitometer.

The pattern of hair loss and the family history are also important in the diagnosis.

Stress more commonly produces telogen effluvium, a generalized shedding that is not associated with miniaturization and is often reversible without treatment.

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Q: I am a 34 year woman with a patch of hair loss by my temple. I went to the salon to have my hair done and to my surprise my hairdresser told me that I have Alopecia? First time I’d heard of it, my G.P is not very concerned about it but having read so much about it on this site I am becoming a bit concerned. The rest of my hair is healthy any suggestions and diagnosis? — M.V., Williamsburg, Brooklyn

A: “Alopecia” is just a generic term for any kind of hair loss.

It sounds like you have a specific condition called alopecia areata. Alopecia areata is an autoimmune disease that presents with the sudden appearance of well localized bald spot(s) on the scalp or other parts of the body. The underlying skin is always normal.

The treatment is injections with cortisone. Hair transplant surgery is not indicated for this condition.

You should see a dermatologist to confirm the diagnosis and treat.

Other diagnoses to consider are triangular alopecia (which would have been present since childhood) and traction alopecia (that is cased by constant tugging on the hair).

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Q: Dr. Bernstein, a lot of older women are taking testosterone to restore libido, but are they going to experience hair loss as a consequence?

A: They can. In women there is a delicate balance between the androgens, i.e. testosterone and estrogens. Estrogen is protective to some degree against hair loss in women, which is why most women don’t experience such severe hair loss as do men.

When a woman takes testosterone supplements it upsets that balance and can cause hair loss. However, hair loss in post-menopausal women is usually due to age related changes. Typically, the hair decreases in size in a genetically determined progression that seems not to be directly related to changes in the levels of hormones.

For more information, please see the Causes of Hair Loss in Women page on the Bernstein Medical – Center for Hair Restoration website.

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Q: One of the things that I have noticed as a person who has needed to take thyroid medication for a long, long time, is that when my thyroid gets a little bit out of balance – when I’m not getting quite enough, I begin to notice is that my hair starts falling out. What about the role of thyroid for hair loss? — T.K., Mineola, NY

A: Both increases and decreases in thyroid levels can cause hair loss and changes in the levels of thyroid hormone can change the consistency of one’s hair. Elevated hormone levels cause scalp hair to be fine and soft, with diffuse thinning being relatively characteristic.

When thyroid hormone levels are low, the hair becomes dry, coarse, and brittle. Hair loss can be either patchy or diffuse (involving the entire scalp).

Low levels of thyroid hormone are associated with the loss of the outer 1/3 of the eyebrows and a decrease in body hair. When changes in thyroid hormone levels are abrupt, there can be dramatic shedding (telogen effluvium).

The most important thing to do if you have thyroid disease is to try to keep the levels within a normal range and keep them as steady as possible. If you are taking thyroid medications, try to use them on a regular basis, because alterations of ones in hair can be caused by large fluctuations in the levels, as much as by the absolute values.

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Q: I know that I am going to be bald because my father is bald and I am losing my hair just like him. What actually causes this kind of hair loss? — J.P., Paradise Valley, Arizona

A: Although there are many different causes, the overwhelming number of people that have hair loss have what is referred to as “patterned hair loss” or “androgenetic alopecia.”

In men, it is due to a hormone called DHT, which is a by-product of testosterone produced by the action of the enzyme 5-alpha reductase. This enzyme is inhibited by the hair loss medication Propecia. See the causes of hair loss in men page on the Bernstein Medical – Center for Hair Restoration website for more information.

In women, the mechanism is a little bit more complex as another enzyme, aromatase, is involved in the metabolic pathway. See the causes of hair loss in women page on the Bernstein Medical – Center for Hair Restoration website for more information.

We know that the inheritance comes from both the mother’s and father’s side, although the actual genes causing hair loss in men and women have not yet been identified. Statistically, the inheritance from the maternal side appears to be a bit stronger, but the reason for this is unknown.

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Q: Why do some people have a full head of hair into their seventies or eighties and others start to go bald in their late teens or early twenties?

A: The cause is genetic and this poly-genetic trait can be inherited from the mother’s side, the father’s side, or both.

There is an old wives’ tale that it is inherited only from the mother’s parents. Although the inheritance can come from either side, it is actually greater from the mother’s side – but only slightly.

Read about Hair Loss Genetics

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Q: It is my understanding that as a person loses his or her hair, the skin of the scalp undergoes a number of changes, namely there is a loss of fat, an increase in cellular atrophy, and of course the dreaded perifollicular fibrosis (now that’s a mouthful). It seems to me that these changes, in particular the fibrotic scarring, are the main obstacles in the way of regrowth, and the reason Propecia does not work for extensively bald men. What can be done about this demon we call fibrosis? Can it be slowed, stopped, prevented, reversed? If we could somehow counteract collagen formation, wouldn’t our baldness problems be solved for good? If a bald scalp is atrophic, how does it have the capacity to hold a whole new head of transplanted hair? Is there a limitation to the number of hairs we can transplant (outside of donor limitations)? — R.L., Rivington, C.T.

A: The findings that you are describing are well documented; however, it is not clear if these changes are the cause of the hair loss or are the result of having lost one’s hair. Most likely, the DHT causes the hair follicles to miniaturize and eventually disappear. This, in turn, causes the scalp to thin and lose its abundant blood supply (whose purpose is to nourish the follicles). The changes in the scalp are also affected by normal aging, which causes alterations in connective tissue including the breakdown of collagen and other components of the skin. The changes seen with aging are greatly accelerated by chronic sun exposure.

Fortunately, even with long-standing baldness there is still enough blood supply to support a hair transplant, although there are some limitations. One should perform a hair transplant with a lower density of grafts when patients have thin, bald fibrotic scalps since the blood supply is diminished.

The most important factor, however, is photo change. The sun dramatically alters the connective tissue making the grafts less secure in their sites and alters the vasculature, (blood vessels) decreasing tissue perfusion (blood flow to the tissues). When there is bald atrophic, sun damaged scalp, I generally perform two hair transplant sessions of lower density (in place of one) spaced at least a year apart to give time for the scalp to heal and blood flow to increase in the area.

I often have the patient treated with topical 5-flurouracil before the surgery to improve the quality of the skin and to treat or prevent pre-cancerous growths from the sun.

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Hair transplant surgeon Robert M. Bernstein M.D. was recently interviewed on the National Public Radio program The People’s Pharmacy. Invited to speak about hair loss, Dr. Bernstein offered insights about the causes of hereditary baldness and it’s solutions, including hair transplantation.

The show was entitled “Dealing with Hair Loss” and addressed issues such as the importance of hair to our sense of well being.

The full hour radio interview was filled with informative facts about male pattern baldness, cultural attitudes toward hair loss and surgical hair restoration. For example, Dr. Bernstein was asked about his pioneering work in follicular unit hair transplantation and host of other questions ranging from the causes of hair loss to the psychological effects of balding. Here is one exchange from the interview:

Moderator: How one can tell the difference between hair loss from hormonal imbalances and common baldness?

Dr. Bernstein: Measuring hormone levels alone, although important for medical management, does not necessarily reveal whether the cause of the hair loss is actually hormone related or is genetic. The diagnosis is made by examining the scalp and looking at the hair under close magnification using an instrument called a “Densitometer.” If the hair shafts are of different calibers, this is relatively diagnostic of female patterned genetic hair loss and in this case hormone levels are often normal. Hormonal changes or imbalances, on the other hand, may cause alterations in hair texture (such as in thyroid disease) or a generalized shedding that can occur after childbirth (called telogen effluvium). In telogen effluvium, the hair can l actually fall out in clumps – you can literally get handfuls of hair, but the hair often returns over time. In genetic hair loss, however, it is not a question of the hair falling out any faster, but the hair being replaced with thinner, finer hair in each hair cycle, until the hair gradually disappears.

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