Estrogen is a group of steroid hormones that play a crucial role in the development and functioning of both female and male reproductive systems, although it is primarily associated with female physiology. The three main types of estrogen are estradiol, estrone, and estriol, with estradiol being the most potent and prevalent during the reproductive years.
In women, estrogen is produced mainly in the ovaries, but smaller amounts are also synthesized in the adrenal glands and adipose tissue. Estrogen regulates the menstrual cycle, supports the development of secondary sexual characteristics such as breasts and pubic hair, and prepares the uterine lining for pregnancy. It also helps maintain bone density, affects fat distribution, and influences mood and cognitive functions.
During the menstrual cycle, estrogen levels fluctuate, peaking during the mid-cycle (ovulation) and then declining if pregnancy does not occur. This hormonal variation is crucial for the cycle's phases, including the follicular phase, ovulation, and the luteal phase.
In men, estrogen is present in lower levels and is produced mainly through the conversion of testosterone by the enzyme aromatase. Estrogen in men is essential for modulating libido, erectile function, and spermatogenesis. It also plays a role in bone health and cardiovascular function.
Abnormal estrogen levels can lead to various health issues. In women, low estrogen levels can cause symptoms like hot flashes, night sweats, and osteoporosis, commonly seen during menopause. High estrogen levels can lead to conditions such as polycystic ovary syndrome (PCOS), endometriosis, and an increased risk of breast and uterine cancers. In men, high estrogen levels can result in gynecomastia (enlarged breast tissue), infertility, and decreased libido.
Estrogen therapy is commonly used to treat symptoms of menopause and other hormonal imbalances. This therapy can be administered in various forms, including pills, patches, gels, and creams. However, estrogen therapy must be carefully managed due to potential risks such as blood clots, stroke, and hormone-sensitive cancers.