What hormones affect scalp hair loss in women
The content of the article:
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Hormones and hair
- Androgens
- Estrogens
- Thyroid hormones
- Prolactin
- Melatonin
- A growth hormone
- Parathyroid glands
- Corticosteroids
- Video
Hair loss is a physiological process and is the result of the growth and renewal of skin cells and its appendages. If more than 80-100 hairs are lost daily, then this is already a pathology. In addition to hereditary factors, nutritional characteristics, environmental conditions, hormones affect hair loss in women on the head, and which of them and how, we will consider in more detail.
In women, a variety of hormonal disorders can be responsible for scalp hair loss
Hormones and hair
Skin and hair are target organs for many biologically active substances. The imbalance of hormones is reflected in the hair follicle, which is sensitive to the changing conditions of hormonal regulation. The growth and loss of hair is influenced by female and male sex steroids, adrenal hormones, thyroid and parathyroid glands, prolactin, somatotropin and melatonin.
Androgens
Male sex hormones - androgens, are produced not only in the body of men, in women they are produced by the ovaries and adrenal cortex. An increased amount of the main androgen, testosterone, is the most common cause of pathological hair loss in women, called alopecia, or baldness. There are several types of alopecia:
- androgenic or androgenetic;
- diffuse or symptomatic;
- focal or nested;
- cicatricial.
The most common - androgenetic, proceeding according to the so-called male type, leads in women to thinning hair in the central parting and lateral surfaces of the head.
Male steroids mediate their effects through a number of mechanisms.
| Scope of application | Mechanism of action |
| Hair papilla (area of the skin with blood vessels and nerves that nourishes the hair root) | Androgens bind in papilla cells to special receptors and block the production of factors responsible for the division of stem cells in hair follicles. This prevents the hair from reproducing at the same intensity or makes it impossible to grow. |
| Skin around hair follicles | With androgenetic alopecia, the scalp becomes thinner, its blood supply and tissue oxygenation deteriorate, and as a result, the follicles are located superficially: the immersion depth is about 1 mm. Normally, in women, the depth of the hair follicle in the scalp is approximately 3 mm. |
| Hair follicle orifices |
At first, some hairs still remain, but they become thinner and discolored - the scalp appears through them. After several years, the mouths of the follicles are overgrown with connective tissue, and even such hairs stop growing. |
The sensitivity of receptors to androgens, and hence the likelihood of developing androgenic alopecia, largely depends on heredity. It has been proven that the predisposition to hair loss in 70-75% of cases is transmitted from the mother and only 20% from the father. The remaining 5-10% is due to baldness in persons who have become the first in the family.
Estrogens
Close relationship and general metabolism with male sex steroids are estrogens, or female sex hormones. But only the effects that they have on the state of the hair are diametrically opposite to the influence of androgens.
Estrogens modulate the hair growth cycle, which is represented by several sequentially replacing periods.
| Period name | Period duration | Hair Processes |
| Anagen - growth period | 2-4 years |
Active growth. The growth rate depends on the season: in winter, the scalp grows more intensively. |
| Catagen - intermediate period | 2-3 weeks | Growth is stopped, pigment is not formed, but the functionality of the hair papilla is preserved. The papilla itself gradually moves to the surface of the skin. |
| Telogen - dormant period | 3-4 months | Growth has stopped completely. The hair falls out on its own or is easily removed when a new one begins to grow from the preserved papilla under it. |
Estradiol, which is the main and most active representative of estrogen, prolongs the first period of the life cycle - the growth phase. This is confirmed by the pattern observed in pregnant women. During gestation, the level of estrogen in a woman's body increases, which leads to an increase in the number of actively growing hairs and their total number on the head.
After delivery, the estrogen content decreases, and hair that has been growing longer than usual, synchronously begins to leave the head. The hairline is thinning, but only for a while. The normalization of the hormonal balance returns the hair to its previous appearance.
After menopause, when the amount of estrogen is also reduced, similar changes occur. The density of the hair decreases, but in this case the process is not temporary, since the functional activity of the ovaries stops completely.
In addition to the direct stimulating effect on the hair follicle, estrogens further reduce the negative effects of androgens. This becomes possible due to the ability of estrogens to inhibit the activity of the reductase enzyme, which converts testosterone into its biologically more active form - dihydrotestosterone.
Hair density decreases after menopause
Thyroid hormones
In addition to androgenic, diffuse alopecia is common in women, in which hair falls out evenly over the entire surface of the head. This type of alopecia has no name, such a loss is often called symptomatic, since it occurs due to malfunctions in the work of the whole organism.
There are two forms of diffuse alopecia:
- anagenic - disrupts the process of active growth;
- telogen - provokes the early onset of a dormant period.
In women, the telogen form is more common, in which, as a result of pathological exposure, more than half of the hair follicles prematurely go into the resting phase.
T3 and T4 control oxygen consumption, protein synthesis and cell division and therefore influence the formation and growth of the scalp.
| Thyroid function, number of T3 and T4 | The cause of the hormonal imbalance | The rendered effect |
| Hyperfunction of the gland, excess of thyroid hormones - hyperthyroidism | Diffuse toxic goiter, nodular toxic goiter, subacute thyroiditis, hormone-active pituitary adenomas, pituitary form of resistance to thyroid hormones, ovarian teratomas, excessive intake of iodine. | Uniform shedding, the remaining hairs are soft, thinned, straight, difficult to permanently curl. The scalp is warm and moist due to peripheral vasodilation and increased sweating. |
| Gland hypofunction, thyroid hormone deficiency - hypothyroidism | Congenital underdevelopment or absence of the thyroid gland, removal of the gland, radiation therapy, medication, genetically determined violation of the synthesis of thyroid hormones, autoimmune thyroiditis, iodine deficiency, dysfunction of the anterior pituitary gland, impaired synthesis and transport of the hypothalamic hormone - thyroliberin. | Gradual diffuse hair loss, they are dull, rough, brittle. The rate of their renewal is slowed down due to the increase in the share in the telogenesis phase. The skin is dry. |
Unlike androgenic, with diffuse alopecia, the death of the hair follicle does not occur, and complete restoration of the hairline is possible within 4-9 months after the cause that led to baldness is eliminated.
Prolactin
Prolactin is produced by the pituitary gland and provides lactation. The main target for prolactin is the mammary glands, but receptors for it are found in many organs, including the skin. The effect on hair follicles is realized through the regulation of the level of sex steroids. In women, prolactin reduces estrogen levels by suppressing ovulation in the ovaries and increases the production of androgens by the adrenal cortex. Hyperprolactinemia - a high content of prolactin in the blood - has an especially negative effect on hair growth.
Melatonin
Melatonin, produced by the pineal gland, is the main regulator of human daily and seasonal biorhythms. Peripheral organs are not only a target for the hormone, but also a site for its synthesis and metabolism. The skin and hair follicles both synthesize and respond to melatonin. Melatonin is involved in the regulation of the hair growth cycle by activating the anagen phase. In addition, the hair follicle uses melatonin synthesis as a defense, since the hormone has free radical scavenger properties.
A growth hormone
Growth hormone, which is a pituitary hormone, controls the linear growth of bones and is involved in all types of metabolism. Somatotropin causes many of the effects directly, but most are realized through the insulin-like growth factor 1 (IGF-1) synthesized in the liver. The skin contains receptors for IGF-1, so IGF-1 through the hair papillae of the skin is able to activate hair growth, stimulating the intensity of cell division in the hair follicles.
Parathyroid glands
The parathyroid glands produce parathyroid hormone, which regulates calcium levels in the body. Congenital absence of glands, their surgical removal, impaired secretion of the hormone or the sensitivity of receptors to it lead to an imbalance of phosphorus-calcium metabolism. The condition when there is not enough parathyroid hormone is called hypoparathyroidism. It manifests itself in involuntary painful muscle contractions, and in relation to hair, thinning or complete loss.
Corticosteroids
Corticosteroids are a type of steroid hormone synthesized by the adrenal cortex. Cortisol is one of the biologically active members of this group. Congenital or acquired dysfunction of the adrenal cortex leads to a lack of cortisol, increased stimulation of the organ and the accumulation of adrenal androgens, which negatively affect the hair follicles.
A large number of hormones in women are responsible for the growth of scalp hair. This must be taken into account when diagnosing, as well as choosing medicines and folk remedies for the treatment of alopecia.
Video
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
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