Estrogen, the female sex hormone, is essential for female growth and reproduction. It plays a major role during puberty, helping with the formation of breasts and other physical changes. In mature women, it triggers ovulation and is responsible for breast growth during pregnancy. Other hormones, such as progesterone and testosterone (the male sex hormone), also affect change in the female body.

Twenty Something

In the 20s, the body produces all three hormones in preparation for pregnancy. Women actually produce more testosterone than estrogen at this age, but the effects are minimal because the amount is so low in comparison to men (about 1/10).

30s-40s

In the 30s and 40s, estrogen and progesterone production are reduced. Fertility declines as hormone levels fall. Women start producing other hormones such as glucagon, the hormone that triggers the release of sugar into the blood. With more sugar available to fuel body processes, women burn less fat.

50s-60s

At age 50, your body produces half of the hormones it produced when you were 25. By 51, most women have hit menopause, the cessation of menstrual periods , meaning a 75 percent decrease in estrogen production. The pituitary gland starts producing more LH and FSH hormones, which cause hot flashes. Some women experience sudden mood swings or depression. Many women begin taking Hormone Replacement Therapy at this age.

70s and Beyond

By age 70, the body is producing about ten percent of the hormones it used to. The pineal gland in the brain produces less and less melatonin, the hormone that governs the body's natural rhythms, making it harder to sleep through the night.