In women, estrogen is produced mainly in the ovaries. Estrogen is also produced by fat cells and the adrenal gland. Men produce estrogen as well, but at lower levels than women. Estrogen in males is secreted by the adrenal glands and by the testes. In men, estrogen is thought to affect sperm count. Overweight men are more commonly affected by low sperm count due to estrogen because there is more adipose tissue in the obese.

Estrogen is instrumental in bone formation, working with vitamin D, calcium and other hormones to effectively break down and rebuild bones. As estrogen levels start to decline in middle age, the process of rebuilding bones slows, leading to more bone breaking down than produced. Therefore, estrogen is important for osteoporosis prevention.

There have been numerous clinical studies that support the potential role of estrogens in reducing the risk for Alzheimer’s Dementia (Simpkins et al., 2009). Support for this hypothesis includes the observation that estrogen therapy can reduce the cognitive decline observed in women that have gone through either natural or surgical menopause.

Estrogen and the cardiovascular system: Studies have shown that estrogen affects almost every tissue or organ system, including the heart and blood vessels. Estrogen’s known effects on the cardiovascular system include increases HDL cholesterol (the good kind), decreases LDL cholesterol (the bad kind), dilates blood vessels so blood flow increases and soaks up free radicals, naturally occurring particles in the blood that can damage the arteries and other tissues.