Estriol
Big things come in small packages.
Estriol is known as the weak sister of the estrogen trio (estradiol, estrone and estriol), BUT don't be fooled. Maybe you've heard of the "butterfly effect," in which "small variations of the initial condition of a dynamic system may produce large variations in the long term behavior of the system." In other words, sometimes something small or weak can make a major difference. That definitely applies to the use of estriol in bioidentical hormone replacement therapy!
Three forms of estrogen occur naturally in a woman's body. The ovary produces a form named estradiol, which is converted into another important estrogen called estrone. Estriol, yet another form of estrogen metabolized from estradiol, is not as strong at the other two estrogens but is still active and essential. Estriol is most commonly linked to pregnancy because it is produced in the most measurable amounts during that time. Estriol is still present throughout a woman's lifetime at varying levels and will fluctuate throughout the day.
Because estriol has been considered a by-product of another form of estrogen and too weak to actually matter, it has been largely overlooked as a beneficial piece of the hormone pie.
Studies suggest estriol can help reduce a variety of symptoms associated with perimenopause and menopause, including:
- Hot flashes
- Vaginal dryness
- Bone density
Research also points to the benefits of estriol for heart health, post-menopausal urinary tract health and protection against osteoporosis.
In essence, estriol's strength is actually found in its weakness. Tests show that while relieving the symptoms of perimenopause and menopause, estriol doesn't seem to increase the risk of breast cancer. This is because estriol binds to the estrogen receptors on the breast cells, but it has much weaker activity. Therefore, it actually blocks the stronger estradiol from binding to those cells and subjecting them to the higher estrogenic activity which has been shown to be protective against breast cancer. Women who have difficulty tolerating stronger estrogens for the treatment of hormonal imbalance due to aging have found estriol is often the right choice.
LifeTime Health Center may choose to test your estriol levels if you are experiencing symptoms of perimenopause or menopause.