The two main sex hormones in women are estrogen and progesterone. Both are produced in men and women, although in different quantities. Progesterone is made from pregnenolone, which in turn comes from cholesterol.



Progesterone is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species.

It belongs to a group of steroid hormones called the progestogens and is the major progestogen in the body

Production of progesterone occurs at several places. In women, it is primarily produced in the ovaries just before ovulation and increases rapidly after ovulation. It is also produced in the adrenal glands in both sexes and in the testes in males. Its level is highest during the ovulation period (day 13-15 of the menstrual cycle).

If fertilization does not take place, the secretion of progesterone decreases and menstruation occurs. If fertilization does occur, progesterone is secreted during pregnancy by the placenta and acts to prevent spontaneous abortion. About 20-25 mg of progesterone is produced per day during a woman's monthly cycle. Up to 300-400 mg are produced daily during pregnancy. During menopause, the total amount of progesterone produced may decline to less than 1% of the pre-menopausal level.

Progesterone in addition to being the precursor to estrogen is also the precursor of testosterone and the all-important adrenal cortical hormone cortisol.

Cortisol is essential for stress response, sugar and electrolyte balance, blood pressure, and general survival. In short, progesterone serves to promote the survival and development of the embryo and fetus. It acts as a precursor to many important steroid hormones and helps to regulate a broad range of biological and metabolic effects in the body. During chronic stress, progesterone production is reduced as the body favors cortisol production to reduce stress. This is an important point which we will look into later.

Progesterone acts primarily  (opposite to) estrogen in our body. For example, estrogen can cause breast cysts while progesterone protects against breast cysts. Estrogen enhances salt and water retention while progesterone is a natural diuretic. Estrogen has been associated with breast and endometrial cancer, while progesterone has a cancer-preventive effect.

Some of the functions of progesterone include:

  • Helps Use Fat for Energy
  • Facilitates Thyroid Hormone Action
  • Natural Anti-depressant
  • Natural Diuretic
  • Normalizes Blood Sugar Levels
  • Restores Libido
  • Normalizes Menstrual Cycles
  • Normalizes Zinc & Copper Levels
  • Normalizes Blood Clotting
  • Protects Against Breast Fibrocysts
  • Precursor for Cortisone Production (Arthritis)
  • Stimulates Osteoblast Cells (they are necessary for the bone-building process)

Progesterone and Osteoporosis

For many years, estrogen was given routinely with the hope that it would prevent osteoporosis. It is now well established that estrogen replacement therapy does reduce osteoporotic fractures by 50 percent. Estrogen works by preventing increased bone resorption during menopause.

However, estrogen has no effect on bone formation; therefore, it does not reverse osteoporosis. Furthermore, when estrogen is discontinued, the rate of bone resorption resumes and the rate actually is accelerated. To be successful, estrogen replacement should be started early (before significant bone loss has occurred) and be maintained indefinitely.

It is important to note that a lack of estrogen does not cause osteoporosis. For example, it is proven that there is significant bone loss during the 10 to 15 years before menopause, despite an ample supply of estrogen during this period. But during that same period, there is often a shortage of progesterone. Although estrogen inhibits the bone-destroying osteoclast cells, it cannot rebuild bone. Progesterone, on the other hand, is a bone builder. It does so by stimulating the osteoblast cells that rematerialize and restore bone mass. Supplementing with bioidentical progesterone has proven useful in the prevention and reversal of osteoporosis. In other words, progesterone is the key to healthy bones, in addition to magnesium (and not calcium alone).

For reliable, affordable, at-home testing check our AdvancedPlus Hormone Panel

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