This article explains the causes, prevention methods, and treatments for hair loss (especially male pattern baldness).

<Things You Should Know> The Right Knowledge About Hair Loss: Explanation of the causes, prevention methods, and treatments for hair loss (especially male pattern baldness).

According to a survey on awareness of hair loss (male pattern baldness) among adult Japanese men, approximately 30% of men aged 20 to 60 are aware of thinning hair. Recent research has advanced and the causes are gradually becoming clearer. Under the supervision of a specialist, we will explain in detail what the causes are, whether there are preventive measures, what treatment options are available, and the relationship with female hair loss. We will also answer frequently asked questions from people suffering from hair loss.

About hair loss in men

About hair loss in men​

This article explains the mechanisms and characteristics of male pattern baldness, as well as how it differs from hair loss. We'll also look at areas that are more prone to thinning hair.

What is thinning hair?

Hair follicles, small organs in the skin that produce hair, go through a cycle of growth, regression, and resting phases (hair cycle). When male hormones act on hair follicles, signals that suppress hair growth are enhanced at the base of the follicle, shortening the growth phase and relatively lengthening the resting phase. As a result, the hair follicles repeat the hair cycle without growing sufficiently, and the hair follicles become smaller (miniature). Consequently, each individual hair produced becomes thinner (vellus), a condition known as male pattern baldness (AGA). Generally, when people refer to thinning hair in men, they are referring to this male pattern baldness (AGA).

Areas prone to hair thinning

Hair follicles in the forehead and crown of the head are easily affected by male hormones, and the M-shaped pattern, where the forehead thins, and the O-shaped pattern, where the crown thins, are well-known as typical AGA (androgenetic alopecia) patterns.

The difference between hair loss and thinning hair

Under normal hair growth cycles, it's said that 50 to 100 hairs fall out each day. This is a normal physiological phenomenon, so there's no need to worry. However, if you notice a significant increase in the amount of short, thin hairs you lose, it could be a sign of hair thinning.

Percentage of men who are aware of hair loss

According to a survey conducted from June to August 2003 among Japanese men aged 20 to 69 residing throughout Japan *, 1,886 out of 6,509 respondents (30%) reported being aware of thinning hair or hair loss. Furthermore, approximately 60% of those respondents indicated they were concerned about the current or future state of their hair (the sum of those who answered "very concerned" or "concerned"). Applying these survey results to Japan's projected population (2003 medium-variant projection), it is estimated that there are 12.6 million adult men nationwide who are aware of thinning hair, and that 5 million men are currently taking some kind of action to address thinning hair.

*Satoshi Itami, "A Survey on Awareness of Hair (Male Pattern Baldness) Among Adult Japanese Men," Nihon Iji Shinpo (4209), 27-29, 2004-12-25, Nihon Iji Shinpo Co., Ltd.

How men experience hair loss and its main causes

​How men experience hair loss and its main causes

Let's explain the hair growth cycle in a little more detail.

Most of the hair cycle is the growth phase. During the growth phase, cells called hair matrix cells, located in the hair root, repeatedly divide, causing the hair to grow. After the growth phase (2-6 years) ends, the hair enters the regression phase (2-3 weeks), where the swollen part of the hair root containing the hair matrix cells (hair bulb) shrinks, and the hair follicle contracts towards the skin, entering the resting phase (3-4 months). During the resting phase, the hair bulb completely regresses, and a hair with a club-like shape at the end remains in the hair follicle. The old hair falls out, "pushed out" by new hair that has begun to form deep within the hair follicle. A new growth phase begins, and the new hair starts to grow in the same hair follicle as the old hair. This cycle of hair follicle regeneration is the hair cycle *1.

  • Hair structure (diagram)

    Hair structure

  • Normal hair cycle and hair cycle in AGA (diagram)

    Normal hair cycle vs. AGA hair cycle

Furthermore, it has become clear that, in addition to male hormones, genetic predisposition also plays a role in hair loss in AGA. In other words, if there are people with a history of hair loss in your family, the likelihood of developing AGA is relatively higher. *2​
In men, it often develops in their 30s or 40s, but in some cases it can develop in their late teens. Across all age groups, one-third of men show symptoms of AGA. *3

source
*1: Manabu Oyama [Editorial Planning], Norimitsu Saito [Author], "Derma. No. 252 (January 2017 issue)", p. 2, Zen-Nippon Hospital Publishing Co., Ltd.
*2: Satoshi Itami [Supervisor], Hair Medical Special Coverage Team [Authors], "The Cutting Edge of Hair Medical Care," pp. 7-15, Asahi Shimbun Publications.
*3: Manabu Oyama [Editorial Planning], Norimitsu Saito [Author], "Derma. No. 252 (January 2017 issue)", p. 5, Zen-Nippon Hospital Publishing Co., Ltd.

Main causes of hair loss

As explained above, it is known that male hormones are the primary cause of AGA (androgenetic alopecia).
There is no scientific basis for the commonly held beliefs that wearing a hat causes hair loss or that clogged pores cause hair loss. Furthermore, the relationship between smoking, lack of sleep, and hair loss is also unclear.
However, the hair matrix cells that produce hair are among the most rapidly dividing and multiplying cells in the body, so they require a lot of nutrients. Just as extreme dieting can cause hair loss, a lack of nutrients is bad for hair. Eating a well-balanced diet is important for maintaining healthy hair.

Hair follicle stem cells and hair loss

In age-related hair loss, which often accompanies AGA (androgenetic alopecia), it has been found that "hair follicle stem cells," which are responsible for sending cells to the hair matrix, are lost. In addition, repeated stress such as plucking or pulling the hair too hard can also reduce hair follicle stem cells.
For example, in trichotillomania, a disorder in which a person cannot stop pulling out their hair, it is thought that pulling out large amounts of hair accelerates the hair cycle, and if this condition continues for a long period of time, the hair that grows back will become very thin. Also, ballet dancers who tie their hair up tightly on a daily basis, and geishas who wear traditional Japanese hairstyles, may experience thinning hair at the hairline, and eventually hair may stop growing alopecia (traction alopecia). One possible reason for this is that the strong pulling puts a strain on the hair follicle stem cells, damaging them.

Common types and symptoms of hair loss in men

Common types and symptoms of hair loss in men

Hair thinning can occur for reasons other than AGA (androgenetic alopecia) or age-related hair loss. Let's look at some of these cases.

Symptoms

  • Hair loss due to hyperthyroidism, hypothyroidism, or collagen disease

    Endocrine and metabolic disorders, as well as collagen diseases, can cause thinning hair and hair loss. A characteristic feature is that it often occurs not only on the crown but throughout the entire scalp. With proper diagnosis and treatment, improvement in symptoms can be expected.

  • Hair loss caused by anticancer drugs

    Hair loss is a common side effect of anticancer drugs used in cancer treatment. Not everyone who undergoes anticancer drug treatment experiences hair loss; the degree varies depending on the type and amount of medication used and the administration schedule. When hair loss does occur, it often begins 1 to 3 weeks after administration of anticancer drugs. In addition to scalp hair, hair loss can also occur in other body hair such as eyebrows, eyelashes, armpit hair, and pubic hair. Hair usually grows back 3 to 6 months after the end of anticancer drug treatment, but the newly grown hair may differ in texture and color from the original hair. Topical prostaglandin preparations can be effective for eyelash thinning caused by anticancer drugs.

  • Alopecia areata

    Alopecia areata is a condition in which the immune system, which normally protects the body from pathogens, malfunctions, causing an autoimmune response that mistakenly identifies parts of the body as foreign substances, resulting in circular patches of hair loss on the scalp. It can occur not only on the scalp but also on other body hair, and the affected areas can vary from one or multiple locations to the entire scalp. Treatment methods differ depending on age, the extent of hair loss, and the time elapsed since onset.

  • others

    Besides the diseases mentioned above, there are many other conditions that can cause thinning hair and hair loss. Thinning hair and hair loss can also occur in inflammatory dermatitis such as seborrheic dermatitis and atopic dermatitis, infectious diseases such as shingles and syphilis, blistering diseases, and other hereditary skin diseases. In addition, thinning hair and hair loss can also occur due to physical factors such as scratching the affected area in itchy skin conditions.

As mentioned above, there are various causes of hair thinning. If you experience symptoms of hair thinning or hair loss, it is important to consult a medical professional and learn about appropriate treatment options.

Hair loss prevention methods

Hair loss prevention methods

As mentioned earlier, the main causes of AGA (androgenetic alopecia) are genetic predisposition and male hormones. Therefore, there are no specific foods or lifestyle habits that can prevent it. Since hair is part of the body, it is generally believed that lifestyle habits that are good for the body will also have a positive effect on hair.

How to deal with thinning hair

​How to deal with thinning hair

When you start noticing signs of hair thinning, such as thin, short hairs falling out, what should you do? Research into AGA (Androgenetic Alopecia) is progressing, and effective treatments have been developed. We will introduce them below.

countermeasure

  • Oral medication

    Male hormones that cause hair loss circulate in the bloodstream and enter the hair follicles, where they are converted into a stronger male hormone (DHT) by the action of enzymes. It is known that this DHT works to suppress hair growth, causing AGA (androgenetic alopecia). There are oral medications called finasteride and dutasteride that suppress the action of this enzyme. By taking finasteride or dutasteride, it is expected that the progression of hair loss will slow down and the appearance of hair will increase.
    However, these medications are not without the risk of side effects such as liver dysfunction, decreased libido, and reduced sperm count. They must be taken under the supervision of a doctor. Furthermore, we do not recommend medications that are not officially approved in Japan, such as overseas drugs or parallel imports, due to safety concerns.

  • Topical medication

    Topical medications containing minoxidil are considered effective. Originally a vasodilator, this drug began to be used as a hair growth stimulant after users experienced increased body hair growth as a side effect. In addition to prescription use, it is also available as an over-the-counter medication at pharmacies with pharmacists on staff.

  • Hair transplantation

    If medication is ineffective, another option is to transplant hair follicles from areas with remaining hair, such as the back of the head, to the crown or forehead. If the transplant is successful, healthy hair with a healthy hair cycle will grow. However, as this is a surgical procedure, there are risks involved. The surgeon must have sufficient experience and a proven track record.

  • LED, low-power laser

    It has been found that LEDs and low-power red lasers also have hair growth-promoting effects. When used with appropriate equipment, side effects are relatively few, so it can be used in combination with other hair growth treatments.

About female hair loss

About female hair loss​

While not as common as in men, many women also suffer from hair loss. Since women also have male hormones, it's possible for them to develop androgenetic alopecia (AGA). However, unlike men, women typically exhibit hair loss that is most noticeable on the crown of the head. In many cases, the link between female hair loss and male hormones isn't as clear as in men, and it's considered a different condition from male AGA. Recently, it's been treated separately as female pattern hair loss. The oral medications mentioned for male AGA are contraindicated for women (should not be taken), so treatment primarily involves topical medications containing minoxidil. While minoxidil topical medications are often associated with men, there are also versions for women. However, while men's over-the-counter medications contain 5% minoxidil, women's versions typically contain 1%.

In addition, women may experience diffuse alopecia (thinning of the hair overall) or telogen effluvium (an increase in the resting phase of the hair cycle) due to aging, and these conditions may overlap with the symptoms of female pattern hair loss described above. In short, the causes of thinning hair are more complex in women than in men.
Regarding the causes, hair loss can be related not only to hormones, but also to nutritional deficiencies such as anemia and dieting, as well as to diseases common in women such as female hormone abnormalities, thyroid disorders, and collagen diseases. Multiple causes may be involved, or the cause may be completely unknown.

If you notice that you're losing significantly more hair than usual when shampooing, you should consult a doctor (dermatologist).

Regarding improving thinning hair and hair loss, there are methods available depending on the condition. In particular, women may be prone to a deficiency in protein, which is the building block of hair, due to extreme dietary habits. In such cases, consuming a balanced diet of protein may improve hair loss. It is also recommended to take care of your scalp on a daily basis to prevent eczema and rashes, which can cause hair loss. Tying your hair tightly on a daily basis can lead to traction alopecia, as mentioned above, so it should be avoided.

Common concerns about thinning hair explained (Q&A)

Common concerns about thinning hair explained (Q&A)

  • If I notice symptoms of thinning hair, should I go to a clinic right away?

    Depending on the degree of hair loss and the individual's willingness to undergo treatment, if it's just a minor concern or a lack of volume, try starting with over-the-counter medications, especially topical minoxidil solutions. It's important to check that there is no itching or irritation on the scalp after starting use, and to use it correctly according to the instructions and dosage.
    If your symptoms worsen after trying over-the-counter medications, we recommend seeing a dermatologist. At the hospital, they can investigate other diseases that may be causing hair loss and prescribe oral medications, allowing for more in-depth treatment.

    Depending on the progression of your symptoms, you may also be referred to a more specialized medical institution.

  • Please tell me about the proper way to wash, dry, and style my hair to prevent hair thinning.

    First and foremost, it's important to keep your scalp clean. Washing your hair can also help prevent eczema. Wash your hair at an appropriate frequency depending on your lifestyle and work environment. Be sure to wash gently, taking care not to damage your hair or scalp.
    When drying your hair, it's important to avoid applying excessive force, such as rubbing your hair and scalp vigorously with your hands. Applying too much strong physical stress to the scalp can lead to a condition called trichorrhizosis nodosa, where the hair develops knots and becomes brittle, so be careful.
    Also, tying your hair tightly every day is not recommended as it can lead to traction alopecia.
    Generally speaking, habits that damage your hair can have a negative impact on hair thinning.

  • Are there any seasons when hair loss is more likely to occur?

    According to a British specialist journal *, a study on the "seasonality of hair loss" conducted from 2004 to 2016 revealed that summer and autumn see the greatest amounts of hair loss. Since there is also research data suggesting that the resting phase of the hair cycle, which is associated with thinning hair, is more likely to occur during the transition period from summer to autumn, caution is advised during this time.

    *：British Journal of Dermatology (2018) 178, p978-979

  • Are there any foods that are said to be good for thinning hair?

    It's sometimes said that kelp and hijiki seaweed are good for hair, but there's no proper medical evidence to support this. These seaweeds are green to black and have a long, slender shape, so the association likely stems from their appearance. Be aware that claims that specific foods affect hair growth often lack scientific basis.
    Conversely, drastic dieting or extreme dietary imbalances can lead to protein and zinc deficiencies, which can disrupt hair growth, especially during the growth phase, and result in hair loss. Again, a balanced diet and a regular lifestyle are essential for healthy hair.

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Professor Manabu Oyama
Supervised by: Professor Manabu Oyama, Department of Dermatology, Kyorin University School of Medicine
He holds a PhD in Medicine. After graduating from Keio University, he moved to the United States in 2002 and worked as a visiting researcher in dermatology at the National Institutes of Health and the National Cancer Institute. In 2014, he became an associate professor in the Department of Dermatology at Keio University, and has held his current position since 2015. His areas of expertise include alopecia, autoimmune diseases, regenerative medicine, and stem cell biology.

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