In daily life, hormone replacement therapy, including the use of estrogen alone or in combination with progesterone, has good therapeutic effects on the skin of postmenopausal women. These benefits include increased skin collagen content, skin thickness and elasticity, skin hydration, and surface lipids. So, what is estradiol?
1. Estradiol is an estrogen steroid hormone and the main female sex hormone. It participates in regulating the female reproductive cycle during estrus and menstruation. Estradiol is responsible for the development of female secondary sexual characteristics, such as breast and buttock widening, as well as the distribution pattern of female related fat. During puberty and adulthood, it is crucial for the development and maintenance of female reproductive tissues such as the breast, uterus, and vagina, as well as pregnancy. It also plays an important role in many other tissues, including bone, fat, skin, liver, and brain. Although the levels of estradiol in males are much lower than those in females, estradiol also plays an important role in males.
2. In addition to humans and other mammals, estradiol is also present in most vertebrate and crustacean species, insects, fish, and other animal species. Estradiol is particularly produced in the follicles of the ovaries, but it is also produced in other tissues including the testes, adrenal glands, fat, liver, breasts, and brain. Estradiol is produced in the body through a series of reactions and intermediate products of cholesterol.
3. The main pathway for the production of estradiol is the formation of androstenedione, which is then converted to estrone by aromatase and then to estradiol. Alternatively, androstenedione can be converted to testosterone, which can then be converted to estradiol. After menopause, the ovaries stop secreting estrogen and estradiol levels drop to extremely low levels.
Estrogen receptors and progesterone receptors are detected in the skin, including keratinocytes and fibroblasts. During menopause and beyond, a decrease in female sex hormone levels can lead to skin atrophy, thinning, increased wrinkles, and a decrease in skin elasticity, hardness, and strength. These skin changes accelerate skin aging, which is the result of reduced collagen content, irregular epidermal cell morphology, decreased matrix between skin fibers, and decreased capillaries and blood flow. The skin during menopause also becomes drier due to a decrease in skin moisture and surface lipids (sebum production). As age increases, menopausal estrogen deficiency is one of the three main factors affecting skin aging. Therefore, appropriate supplementation of estradiol in menopausal women can make the skin smooth, delicate, and elastic.
