Androgenetic alopecia

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

• excess levels of the male sex hormone dihydrotestosterone (DHT);
• increased sensitivity of hair follicles to DHT;
• increased activity of the enzyme 5alpha-reductase, which converts testosterone to DHT. By some estimates, androgenetic alopecia accounts for up to 95% of all cases of baldness in men and women.

In men, androgenetic alopecia usually starts at the front of the hairline and moves toward the crown (although other variations are possible). In women, there is progressive thinning and fine hair over almost the entire scalp, especially at the crown.

Hippocrates also noted that eunuchs do not go bald. Later, Aristotle noted the same fact. In the 1940s, Dr. James Hamilton wrote that baldness can be caused by an excess of male sex hormones in combination with genetic predisposition.

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The mechanism of development of androgenetic alopecia

Strictly speaking, it cannot be said that sex hormones suppress or enhance hair growth in general. The effect of androgens or estrogens on 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 a finger that presses this button. The result of pressing the button is predetermined by the mechanisms that are present in the follicle. You can press the same buttons with the same finger, and the result in one case will be an explosion at a military training ground, and in another - the launch of a spaceship. The whole question is what wires are connected to these buttons. Thus, estrogens stimulate hair growth on the head and suppress hair growth on the face and body. Androgens stimulate beard and moustache growth, hair growth in some areas of the body and can suppress hair growth on the head.

Of course, it is not so much about androgens, but about which follicles are located in which areas. If there are follicles on the head that have DHT-dependent "buttons" to stop growth, then in response to the excess of androgens, hair loss will occur. If we transplant follicles from the moustache or beard area to the head, 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 precisely the transplantation of DHT-activated follicles to bald areas.

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

Hair is an important sexual characteristic, and it needs to know whether it should grow on a given area of the body. And this depends on who the 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 male characteristic. But an excess of estrogens will force these same follicles to stop producing hair. Hair follicles located on the scalp are stimulated by estrogens and suppressed by androgens (it is not for nothing that long hair is primarily an adornment for women). If a follicle becomes too sensitive to androgens, then this suppressive effect can become excessive for it.

DHT exerts its suppressive effect in the hair growth phase, and the hair prematurely enters the resting phase. Let us recall that each follicle can be in three different phases of the life cycle - anagen, catagen and telogen. Anagen is the period when the hair follicle produces hair. Usually 85-90% of hair follicles are in the anagen stage, which lasts for several years. Catagen is the period of follicle degradation. Hair growth stops, and the hair root acquires the characteristic shape of a bulb. This phase lasts for several weeks. In the telogen phase, the hair separates from the root and slowly moves towards the surface of the skin. About 10-15% of hair is in the telogen stage. These are the hairs that fall out when combing and washing the head. Normal hair loss is 70-80 hairs per day.

Diagnosis of androgenetic alopecia

A diagnosis of androgenetic alopecia in women can be made if:

• the presence of visible symptoms of androgenic alopecia is noted - progressive thinning and diffuse hair loss, signs of hirsutism and acne;
• Microscopic examination data show the presence of miniaturized follicles;
• by counting the number of hairs in different growth phases, an imbalance is revealed between hair follicles in the growth phase and in the resting phase;
• Based on microscopic examination, it was established that miniaturization of follicles and thinning of hair does not affect the lower occipital region. If there is every reason to talk about androgenic alopecia and the diagnosis can be considered established, then the next problem arises - treatment.

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Treatment of androgenetic alopecia

Treatment for androgenetic alopecia includes:

• specific methods of treatment of androgenetic alopecia;
• non-specific methods common to all types of baldness. Specific methods include anti-androgen therapy, which is carried out using both medicinal and folk (alternative) means. Anti-androgen therapy can reduce hair loss, but usually does not lead to the restoration of the previous thickness of hair. Stimulation of hair growth is carried out using methods common to all types of baldness.

A promising method is selective action on the activity of the enzyme 5alpha-reductase, which converts testosterone to DHT in the skin. The method is attractive because the effects for which testosterone is responsible in the body (spermatogenesis, sexual behavior, muscle mass distribution) remain unaffected. This is especially important for men who are horrified by the words "antiandrogen therapy."

Currently, one of the most effective drugs used to stimulate hair growth in androgenic alopecia is considered to be minoxidil, which is produced under the trade names "Regaine", "Rogaine", "Headway". We will talk about it in more detail in the section on methods of treating alopecia, and now we will only say that minoxidil is the only drug that acts directly on the hair follicles, prolonging the hair growth phase. Other methods of influencing the hair follicles include electrical stimulation, massage, hypnotherapy and electrophoresis of biologically active substances.

Among antiandrogens, there are many medications that should not be taken without consulting a doctor. Moreover, one of the most powerful 5-alpha-reductase inhibitors, finasteride (Propecia, Proscar), is not suitable for treating female androgenic alopecia, as it has a strong embryotoxic effect. For women, the drug "Diane-35" is more acceptable, which is used as an oral contraceptive. In addition to 5-alpha-reductase inhibitors, androgen receptor blockers are used to treat androgenic alopecia in men and women. If the blocker is strong enough, it can affect libido, breast size (in men, gynecomastia is observed), spermatogenesis and potency. The latter is what upsets patients the most, so along with antiandrogens, it is recommended to use yohimbe, arginine and other potency stimulants.

Auxiliary means for the treatment of alopecia include preparations based on plant extracts and natural compounds with antiandrogenic activity. Among them are oils rich in unsaturated fatty acids, extracts of saw palmetto and nettle fruits, vitamin B6, and zinc.

You should be prepared for the fact that the treatment of androgenic alopecia is long-term. The first results from the use of minoxidil and antiandrogens appear after several months. At first, the rate of hair loss slows down, then you can expect a gradual restoration of the thickness of the hair.