Basic Research on Androgenetic Alopecia (AGA) (Vol. 1) Sex Hormone & Hair Loss

Hormonal Changes in the Menstrual Cycle

Female hormones in the serum change cyclically according to the menstrual cycle in women.

Estrogen increases during the follicular phase of the menstrual cycle.

Progesterone increases during the luteal phase.

These changes in hormone levels can affect hair growth.
These hormones belong to the group of steroid hormones.

CYP19 gene encodes Aromatase

Some of estrogens are produced from androgens by the enzyme aromatase in the skin tissue.
Testosterone in the serum is modified to estradiol in the skin tissue by aromatase.

Most of the serum estrogen is produced in the ovaries.
The ovary is rich in aromatase (CYP19).

Aromatase is a complex of cytochrome P450, and it is produced by the CYP-19 gene.


It is still uncertain how estrogen affects hair growth. 

Estrogen slows down the rate of hair growth.

Estrogen antagonists stimulate transmission from the telogen phase to the anagen phase. They induce the telogen phase to the anagen phase in the hair cycle.

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