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Androgenic (hereditary) baldness

Posted on2021-05-03 by
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The article discusses what causes the most common form of baldness - the so-called hereditary baldness (androgenic alopecia) - and what drugs and methods are used to treat it. This form is observed in most men and a significant proportion of women.

The mechanism of development of androgenic alopecia

Androgenic alopecia is hair loss caused by one of the following:

  • excess content of the male sex hormone dihydrotestosterone (DHT);
  • increased sensitivity of hair follicles to DHT;
  • increased activity of the enzyme 5-alpha-reductase, which converts testosterone to DHT.

According to some estimates, androgenic alopecia accounts for up to 95% of all cases of male and female pattern baldness. In men, androgenic alopecia usually starts in front of the hairline and progresses to the crown (although other variations are possible).

Androgenetic alopecia is typical for both men and women.

Models of androgenic (hereditary) hair loss in men and women

In the figures in this article, you can see how the process of thinning in men and women is going on. In the first stage, this is the normal condition of the hair.

In men at the second stage of thinning, the beginning of hair thinning is observed in the area of ​​the crown. At the third stage, the hair thinning zone expanded, and temporal bald patches appeared.

In women with androgenetic alopecia, there is a progressive thinning and thinning of hair almost all over the head, especially in the area of ​​the crown. From the normal state of the hair, they move to the second stage of baldness - there is a noticeable thinning of the hair along the parting. At the third stage of hair loss in women, the hair thinning zone expands along the parting.

A bit of history. Even Hippocrates noticed that eunuchs do not go bald. Later the same circumstance was noted by Aristotle. In the 40s of the XX century, Dr. James Hamilton wrote that baldness can be caused by an excess of male sex hormones in combination with a genetic predisposition.

Strictly speaking, we cannot say that sex hormones suppress or enhance hair growth in general. The result of the action of androgens or estrogens on the hair will be determined by the presence of a special receptor on the surface of the hair follicle cells. The receptor resembles a button, and the hormone is the finger that presses the button. The result of pressing the button is predetermined by the mechanisms that are present in the follicle. You can press the same finger on the same buttons, and the result in one case will be an explosion in Chicago, and in the other - the launch of a spaceship.

The whole question is what wires are connected to these buttons. For example, estrogens stimulate scalp hair growth and inhibit facial and body hair growth. Androgens stimulate beard and mustache growth, hair growth in some areas of the body, and can inhibit scalp hair growth. Of course, it's not so much about androgens as a matter of which follicles are located in which areas. If there are follicles on the head that have DHT-dependent "buttons" for stopping growth, then hair loss will occur in response to an excess of androgens. If we transplant follicles on the head from the mustache or beard area, then the excess of androgens, on the contrary, will cause hair growth on the head. By the way, one of the methods of combating baldness in androgenic alopecia is the transplantation of DHT-activated follicles to areas of baldness.

Women with androgenic alopecia usually have other signs of hyperandrogenic syndrome - excessive facial hair growth, acne and oily seborrhea. However, virilization, that is, the appearance of masculine features of the body structure, is rarely observed. Almost always, both men and women with androgenetic alopecia have normal or slightly elevated blood androgen levels. It is believed that the main cause of hair loss in androgenic alopecia is either an increase in 5-alpha reductase activity or an increase in the sensitivity of receptors to DHT.

The enzyme 5-alpha reductase is present in the body in two forms: type 1 is found in the prostate gland in men, type 2 in the sebaceous glands and hair follicles. The task of the enzyme is to convert testosterone circulating in the blood into an active form - dihydrotestosterone (DHT). It would seem, why would hair follicles convert testosterone to DHT if hair falls out from this? However, this has a deep biological meaning.

Hair is an important gender and needs to know if it should grow in a given area of ​​the body. And it depends on who this body belongs to - a man or a woman. For example, follicles located in the chin area will respond positively to DHT, since a beard is a masculine trait. But the excess of estrogen will cause these same follicles to suspend hair production. Since long hair is a decoration for women, not men, the hair follicles located on the head are stimulated by estrogens and suppressed (suppressed) by androgens. If a follicle becomes too sensitive to androgens, then this suppressive effect may become excessive for it.

DHT exerts its suppressive effect by acting on the hair growth phase, so that the hair enters the resting phase prematurely. In general, each follicle can be in three different phases of the life cycle - anagen, catagen and telogen. Anagen is the time when the hair follicle produces hair. In the anagen stage, which lasts for several years, 85% of the hair follicles are usually found. Catagen - time of follicle degradation. Hair growth stops and the hair root takes on the characteristic bulb shape. This phase lasts several weeks. In the telogenic phase, the hair is detached from the root and slowly moves towards the surface of the skin. About 15% of the hair is in the telogen stage. It is this hair that falls out when combing and shampooing. Normal hair loss is 70-80 hairs per day.

Let's look at the diagram of all the phases of hair growth.

Phases of hair growth and development.

Phases of hair growth and development

In the picture you can see that from the final phase of growth (p. 1) (Anagene) the hair passes into the next stage of Catagene (p. 2). This separates the inner segment from the papilla. Further, the hair follicle is pulled up to the level of the erector muscle (Telogene) - p. 3. Then the hair growth stops, the formation of new hair begins and, in the new phase of Anagene (p. 4), the growing hair "pushes" the bulb of the old hair.

You can also see that from Anagene (item 1) - this is the active stage of hair growth, which takes from 2 to 6 years. The transit stage of Catagen (item 2) lasts approximately 1-2 weeks. The Telogen stage takes approximately 5-6 weeks.

DHT causes a reduction in the hair growth phase in some follicles. These follicles do not reach their maximum size and therefore begin to produce thin and weak hair. Microscopic examination reveals miniaturized, atrophic follicles that are characteristic of androgenetic alopecia. Look at the photo of hair follicles taken under an electron microscope. You can see what a normal follicle (left) and miniaturized follicle (right) looks like under the influence of DHT.

Normal follicle (left) and miniaturized (right) under the influence of DHT.

Normal follicle (left) and miniaturized (right) under the influence of dihydrotestosterone

As the ratio between follicles in the anagen stage and in the telogen stage shifts towards the resting follicles, many follicles appear on the head, which simultaneously shed the hair fiber. As a result, thinning and weakening of hair ends with their progressive hair loss.

Hair follicles contain another enzyme, aromatase, which converts DHT back into testosterone and estrogens. It decreases DHT levels in hair follicles and is a 5-alpha reductase antagonist. In women, the follicles of the frontal scalp area contain several times more aromatase than in men. This, apparently, explains the diffuse and less pronounced nature of androgenic alopecia in women.

In addition, women have DHT-resistant follicles in the occiput, which do not shorten the growth phase when exposed to DHT. Therefore, thinning hair in women usually does not affect the lower part of the back of the head. In men, the lower part of the occiput is also the most resistant to baldness. It is from this area that the follicles are taken for transplant surgery.

Androgenic alopecia in women

The diagnosis of androgenic alopecia in women can be made if:

  1. there are visible symptoms of androgenic alopecia - progressive thinning and diffuse hair loss, signs of hirsutism and acne;
  2. microscopic examination shows the presence of miniaturized follicles;
  3. counting the number of hairs in different growth phases reveals an imbalance between hair follicles in the growth stage and in the resting stage;
  4. microscopic examination showed that follicle miniaturization and hair thinning does not affect the lower occipital region.

If there is every reason to talk about androgenic alopecia and the diagnosis can be considered as made, then the second problem arises - the problem of treatment.

Androgenic Alopecia Treatment

Treatments for androgenic alopecia include:

  1. specific treatments for androgenetic alopecia;
  2. non-specific methods common to all types of baldness.

Specific methods of treating androgenic alopecia include antiandrogen therapy, which is carried out with both medicinal and folk (alternative) means. Antiandrogen therapy helps to stop hair loss, but usually does not lead to the restoration of the previous density of the hair. Hair growth stimulation is carried out using methods common to all types of baldness.

The most effective drug for stimulating hair growth in androgenic alopecia was Minoxidil, which is marketed under the trade names Regaine, Rogaine, Headway and many others. We'll cover minoxidil in a separate article (see list of related articles). For now, let's just say that minoxidil is the only drug that acts directly on the hair follicles, prolonging the hair growth phase. Other methods of affecting hair follicles include electrical stimulation, massage, hypnotherapy, and electrophoresis of biologically active substances.

As for specific antiandrogen therapy, the most promising method here is to influence the activity of the 5-alpha reductase enzyme, which converts testosterone into DHT. This method is attractive in that the effects for which testosterone is responsible (spermatogenesis, sexual behavior, muscle distribution) remain unaffected. This is especially true for men who are horrified by the words "antiandrogen therapy".

Since there are two types of 5-alpha reductase in the human body, one of which is localized in the skin and hair follicles, and the other in the prostate, it is theoretically possible to act on one type of enzyme, without affecting the second. However, in practice, it turns out that even selective inhibitors to one degree or another affect both enzymes.

In addition to 5-alpha-reductase inhibitors, androgen receptor blockers are used to treat androgenetic alopecia in men and women. If the blocker is strong enough, then it can affect libido, the size of the mammary glands (in men, gynecomastia is observed), spermatogenesis and potency. The latter upsets patients the most, therefore, along with antiandrogens, it is recommended to use drugs such as yohimbe, arginine amino acid and other potency stimulants.

Among antiandrogens, there are many medicines that should not be taken without consulting a doctor. Moreover, one of the most potent 5-alpha reductase inhibitors is finasteride (Propecia, Finpecia) is not suitable for the treatment of female androgenic alopecia, as it has a strong embryotoxic effect. Diane-35, which is used as an oral contraceptive, is more acceptable for the treatment of baldness in women. We'll talk more about Diane-35 and other antiandrogenic drugs in the general section on treatments for alopecia, and now we will focus on agents that have a milder antiandrogenic effect and which are called "natural" treatments for androgenetic alopecia.

Recently, the ability to inhibit 5-alpha reductase has been found in many substances. An unexpected find was the antiandrogenic effect of some polyunsaturated fatty acids, especially gamma-linolenic acid. For the first time, the connection of polyunsaturated fatty acids with androgen metabolism was shown in 1992. Later, in 1994, it was proved that gamma-linolenic acid and some other fatty acids are effective inhibitors of 5-alpha reductase. The highest inhibitory activity was observed for gamma-linolenic acid, followed by docosahexaenoic, arachidonic, alpha-linolenic, linolenic and palmitooleic acids in decreasing order. Other unsaturated fatty acids, as well as methyl esters and alcohols of these fatty acids, carotenoids, retinoids and saturated fatty acids did not inhibit 5-alpha reductase even at significant concentrations.

Gamma-linolenic acid is found in large quantities in black currant oil (16% gamma-linolenic, 17% alpha-linolenic, 48% linoleic), borage (20-25% gamma-linolenic, 40% linoleic), evening primrose (14% gamma-linolenic, 65-80% linoleic). Avocado oil has a good composition (30% linoleic, 5% alpha-linolenic, 13% palmitooleic). Despite the absence of gamma-linolenic acid, avocado oil is one of the best treatments for hair, as, due to its high oleic acid content (up to 80%), it has good penetration and a high distribution coefficient. Avocado oil can be added to complex oil formulations to improve absorbency and flow. Docosahexaenoic acid, which also has the ability to inhibit 5-alpha reductase, is found in jojoba oil (up to 20%). Jojoba Oil - the richest source of docosahexaenoic acid among natural oils. Oil formulations with an antiandrogenic effect have the advantage of penetrating well the lipid barrier of the skin and the hair cuticle. They can be used as an adjunct to all types of hair treatments. When applied, the normal structure of damaged hair is restored and the functioning of the sebaceous glands is normalized. On the basis of antiandrogenic oils, emulsion and microemulsion systems can be prepared, with the help of which other biologically active substances will be injected into the scalp skin.

Powerful antiandrogenic effect is possessed by dwarf palm extract Saw Palmetto (Serenoa repens), which is used for the treatment of prostatic hyperplasia. Dwarf Palm Extract acts in two ways at once. Firstly, it inhibits the enzyme 5-alpha-reductase, and secondly, it blocks specific receptors for DHT. No one has carried out special studies to study the effect of dwarf palm extract on hair, but, nevertheless, it is already intensively used to treat androgenic alopecia. Unlike finasteride, dwarf palm extract is safe and can be used to treat female androgenetic alopecia. Saw Palmetto is taken internally as a dietary supplement. There is no information on the external use of Saw Palmetto in the literature, but such therapeutic complexes are already being produced.

Two other substances inhibitory action of which have been 5-alpha reductase recently discovered are vitamin B6 and zinc. Vitamin B6 alters the response of tissues to steroid hormones, including blocking the action of androgens. Zinc when applied topically reduces the activity of the sebaceous glands, reduces the appearance of acne, which indicates its undoubted antiandrogenic effect. Animal studies have shown the ability of zinc to stimulate hair growth. Vitamin B6 is rich in brewer's yeast, therefore nutritional formulas and shampoos with brewer's yeast will have a beneficial effect in androgenic alopecia. Zinc is available as standalone products, such as Organic Zinc or Zincapsa, and as supplements taken by mouth (such as Kordel's Prostaguard, Nutra-Life Saw Palmetto 4000 complex, Hair Vitamins: Extra Strength Professional Formula and others) as well as ointments applied to the skin surface.

If androgens cause baldness, then estrogens, on the contrary, stimulate hair growth on the scalp. However, synthetic estrogens should not be recommended to patients, as they have side effects (phlebitis and induction of tumors, including breast cancer). However, there are substances that show estrogen-like effects, but do not show side effects. These are phytoestrogens, which are chemically similar to human estrogens, which allows them to bind to the same receptors and activate them. True, their estrogenic effect is many times weaker than the effect of estrogens themselves, but they have anti-cancer activity and have a beneficial effect on the skin. Estrogenic action has an extract of hops, seeds and grape peel (Pycnogenol), verbena, wild yam, damiana leaves, St. John's wort, red clover, sarsaparilla, soy, alfalfa, sage. Sage extract, among other things, contains a lot of zinc, which has a antiandrogenic effect. Phytosterols with estrogenic activity are found in wheat germ oil, olive oil, sesame oil, palm oil and coconut oil. Phytoestrogenic extracts can be used internally, or formulated for hair rinsing, electrophoresis and other hair treatments.

We must be prepared for the fact that treatment of androgenetic alopecia is long-term. The first results from the use of Minoxidil and antiandrogens appear several months later. At the same time, at first there is a slowdown in the rate of hair loss, then you can wait for a gradual restoration of the density of the hairline. It is important here that the patient believes that the procedures performed will give an effect, therefore, much depends not even on the procedures themselves, but on the ability of the cosmetologist to explain their meaning and gain understanding and trust from the patient. Patients should be explained that antiandrogen therapy will not only help stop hair loss, but also quickly cleanse the skin from acne, reduce its oily content, and soften the manifestations of hirsutism. If skin improvement occurs soon after the start of antiandrogen use, hair treatment is a lengthy process and will have to be repeated from time to time.

Any auxiliary methods that will help the patient gain faith in treatment are of great importance: massage (manual and using vacuum technology), hypnotherapy, psychotherapy, the use of formulations that improve the structure and appearance of hair, all to help the patient look better and feel more confident. The cosmetologist must do everything so that the patient wants to continue the treatment and does not lose heart without getting a visible result after a couple of sessions.

However, it also happens that, despite persistent treatment, hair growth is not restored and baldness progresses. This is more often observed with androgenic alopecia in men. In these cases, you have to resort to surgical hair restoration. Surgical treatment is carried out in special clinics, but before deciding on it, the patient should be consulted about what kind of technique it is and whether it makes sense to use it.

There are several non-surgical techniques for those who are desperate to restore hair density. Donor hair is either attached to the remaining hair, creating the illusion of fluffiness, or glued in small patches to the scalp.

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