Hormones have the power to make us feel great, but they can also wreck our lives. There are many types of hormones and all have important roles in keeping us balanced and healthy. Hormones balance our sugar level, instruct our cells to generate energy, keep our calcium level normal and our hearts beating regularly, and help our liver detoxify our system even after a 5 martini night.

One particular hormone group reigns supreme: the sex hormones: Estrogen, progesterone, and testosterone. They determine our gender, they are responsible for our outlook on and reactions to life, how we age, and how long we live.

Let's take an average 28 day cycle, when you are not pregnant. Let's start with day 1. You have your period. Your estrogen and progesterone levels are practically nil. The lack of hormones in your system has induced you to get your period. As this scenario unfolds, the increased levels of estrogen produced by the ovary and follicle are now reaching the pituitary and sending a new message to the master gland, "We have enough estrogen here to go ahead and ovulate."

If the pituitary reads the message correctly it starts releasing LH (lutenizing hormone). LH production is turned off by the increasing levels of progesterone. For the last two weeks of the cycle, estrogen and progesterone production are balanced to prepare the body for pregnancy. Progesterone is made by the corpus luteum, the name given to the follicle once expelled from the ovary, now an independent organ responsible for further support and preparation of the egg for fertilization. The progesterone made by the corpus luteum prevents other eggs from maturing and keeps the uterine lining ready for implantation. More than 90% of the body's progesterone is made by this short lived organ. If the woman gets pregnant, the corpus luteum thrives and makes literally gallons of progesterone to nurture and sustain the fetus. If the woman doesn't get pregnant, the corpus luteum shrinks and dies. With its demise, the progesterone production and thus circulating progesterone levels wanes. The cycle has ended and the woman gets her period. The fall of estrogen and progesterone is picked up by the hypothalamus. This signals the start of a new cycle and the hypothalamus heralds it by secreting GnRH.

The cycle repeats itself every month until we either get pregnant or stop ovulating.

Adapted from The Hormone Solution by Erika Schwartz, M.D. Buy the complete book for $13.95 including postage.