““Estriol—Estriol is the weakest of the three estrogens and has a protective role in breast tissue. It is believed to protect vaginal tissue too. Estriol helps to reduce hot flashes in women, protects the urinary tract, and plays a role in retention of bone density. It can help increase “good” HDL and decrease “bad” LDL cholesterol. One compelling study showed that taking estriol can reverse brain lesions in women with multiple sclerosis. Estrogen is particularly needed in women to make serotonin function at its best in the brain. Serotonin is one of the brain’s feel-good hormones. With no estrogen, your mood can change to anxious and depressed. Cognitive functions, such as critical thinking and short-term memory, are also eroded with the loss of estrogen production. Below is a list of symptoms related to low and high estrogen levels:””