Natural Progesterone is Something Women Can Cheer About

Hip, Hip, Hooray for Progesterone
This natural sex hormone can help prevent hip fractures
and other complications of osteoporosis

ome people may think that osteoporosis is inevitable. This certainly is not true. There are many steps that individuals, especially women, can take to prevent, retard, or even reverse the course of osteoporosis. One treatment that has received much attention lately is the use of natural progesterone. This approach is especially beneficial for women with irregular periods and for postmenopausal women.

Osteoporosis is characterized by low bone density and deterioration of bone structure. Put simply, osteoporosis leads to fragile bones that fracture easily. This condition is especially prevalent in older women, who experience bone fractures at a much higher rate than any other segment of the population. Even simple activities, such as opening a window, can place sufficient stress on the bones of individuals with advanced osteoporosis to cause fractures.1

The bones that are most prone to fracture are located in the hip, wrist, and spine. Of these, hip fractures usually pose the most severe threat to one's future health. For example, individuals who break their hip are 10--20% more likely to die in the year following this event, and only one-third of the survivors rebound to their previous level of independence.2 Clearly, it is well worth your while to maintain healthy bones that are resistant to fracture.

Bone tissue is a dynamic structure that can change shape and density in response to specific signals. Bone is initially formed from soft tissue, primarily the protein collagen, which determines its shape and location in the body. As it matures, the forming bone tissue collects solid particles of calcium phosphate, which harden it into a structure capable of resisting compressive forces. Bones are not solid structures, but are interlaced with very small channels that contain cells and blood vessels. In fact, about 15% of bone is composed of live tissue, which allows it to change shape and density over time.

There are two types of cells in the bone that have opposite functions. Osteoblasts release fibrous proteins and bone-forming matrix materials to synthesize and remodel bone. Osteoclasts degrade bone and recycle its components. You want to make sure that your osteoblasts are more active than your osteoclasts, or else you will start to lose bone tissue. As we age, our bone density decreases, which leads to frail and brittle bones that break more easily - osteoporosis.

Bone is sensitive to injury and stress induced by jarring or pounding, and it responds to these activities by reinforcing itself in weak or damaged areas. Repeated stress, such as jumping, activates osteoblasts in your leg bones to synthesize new bone matrix material to reinforce the stressed area. This is well illustrated by the fact that young people who participate in bone-jarring sports, such as wrestling and gymnastics, have higher bone mineral density (BMD) than athletes who participate in less intense sports. BMD is especially high in the pelvises of individuals who subject their bones (and bodies) to jarring impact.

The converse of this equation is also true. For example, astronauts (who experience extended periods of zero gravity) and individuals who must undergo long-term bed rest lose bone mass at an accelerated rate. Individuals confined to their beds for approximately 4 months lose BMD at the rate of about 0.4% per month, while astronauts may lose more than 0.9% per month, or about 11% per year in certain regions of the bone.3 The greatest BMD loss occurs in the weight-bearing bones of the legs and the hips; relatively little is lost from the arms, which are not subject to the compressive forces of gravity. These observations are consistent with the fact that those bones with the greatest density (hip and leg bones, which bear the brunt of the body's weight) are most susceptible to loss of BMD from lack of activity. These results also help to explain why elderly individuals who are inactive suffer hip fractures at an increased rate.

Is there any way to slow bone loss without being slammed onto a wrestling mat repeatedly? Indeed there is. Recent research indicates that impact exercises such as vertical jumping (in basketball or jump-rope, e.g.) are helpful in this respect. The result is much more pronounced in adolescent girls and young women, who can actually increase their BMD. However, postmenopausal women can also benefit if they engage in vertical jumping (to a height of 4-5 inches off the floor) with a weighted vest. Although this activity does not increase BMD, it does prevent loss of bone mass.4 In addition, women who exercise in their golden years are half as likely to suffer from hip fractures as those who do not.5 Christine Snow, Ph.D., an exercise physiologist at Oregon State University, explains these results by suggesting that improved muscle tone from exercise may prevent falls, thus reducing the risk of hip fractures.6

What determines whether osteoporosis is going to occur? There are many factors, including low calcium intake, advanced age, low hormone levels, lack of exercise, and smoking. It may surprise you to know that 99% of the calcium in your body is stored in your bones. If you don't get enough of this mineral in your diet, your body breaks down bone to release it for other needs, such as muscle contraction and the transmission of neuronal signals. Because these functions are so critical, the body is willing to sacrifice bone tissue to provide calcium for the rest of the body. Adequate calcium intake, in a form that the body can absorb, is an essential first step in maintaining a healthy skeletal system.

The relationship between smoking and bone density has not been well clarified, but it has been suggested that smoking decreases calcium absorption from the diet. For this reason, smokers may want to consider calcium supplementation to boost their levels of this vital mineral. (What they should really do is quit smoking, for a host of life-extending reasons.)

Advancing age also prevents robust bone formation, because the levels of our sex hormones, which are essential for this function, decline with age.

As women undergo menopause, their estrogen levels drop dramatically. This is bad news, because the lack of estrogen induces bone resorption - the process by which bone tissue is gradually dissolved and reassimilated into the body - and thus greatly increases the risk of osteoporosis. Much research supports the role played by the female sex hormone estrogen in maintaining bone tissue - in men as well as women. (All men have some estrogen in their systems, just as all women have some testosterone in theirs.)

Adequate calcium
intake, in a form that the
body can absorb, is an
essential first step in
maintaining a healthy
skeletal system.

Men don't suffer the same fate as women, because they produce testosterone at a fairly constant rate throughout their lives, and some of that sex hormone is converted to estrogen. It is true that testosterone production in men does gradually decline with age, but it nowhere nearly matches the precipitous decline of estrogen production in postmenopausal women. Thus,although aging men can be at increased risk for osteoporosis, their risk is not nearly as great as that for women.7

Osteoporosis occurs in women with estrogen deficiency and in women who experience amenorrhea (absence of a menstrual cycle), regardless of age. Estrogen replacement therapy has long been heralded as an important intervention for preserving bone density in postmenopausal women.

A placebo-controlled trial of 875 such women revealed that estrogen treatment induced an increase of 3.5-5% in mean bone mineral density in the spinal column and an increase of 1.7% in the hip, over a 36-month period.8 By contrast, untreated women lost an average of 1.8% BMD in the spinal column and 1.7% in the hip. The greatest increase in BMD occurred in older women, women with lower BMD at the onset of the trial, and women with no previous hormone use. Clearly it is advantageous for women to seek estrogen replacement therapy to increase bone density following menopause.

But are estrogens the only hormones involved in bone growth and formation? No indeed. It turns out that progesterone, another cyclically released female sex hormone, is also very important to bone formation. Progesterone promotes the remodeling and formation of new bone,9 and its action may be completely independent of estrogen function.10 In a 3-year study involving 63 postmenopausal women, transdermal (meaning through the skin) progesterone treatment with 350-500 mg per month resulted in a 2.6-22.4% increase in bone mineral density of the lower back. Women with lower initial BMD values showed the largest increase over the 3-year course of the study, while the benefit was less pronounced in those who entered the study with already high BMD values.

Researchers at the University of California in San Francisco - one of the medical colleges of the UC system - report that women are subject to more extensive bone loss during certain periods (so to speak) of their menstrual cycle. Consistent with the above information, it is not surprising that these periods are characterized by low levels of estradiol (one of the principal estrogen compounds) and progesterone in the blood.11 These results indicate that bone resorption occurs even in younger women and that it is wise to take steps against bone loss at an early age.

Further evidence that bone loss is intimately tied to sex hormones and the menstrual cycle comes from Dr. Kristen Nicodemus and her colleagues at the University of Minnesota School of Public Health, who reported in a recent issue of The American Journal of Epidemiology that women with irregular menstrual periods have an increased risk of hip fracture.12 The researchers noted that neither irregularity in the length of the menstrual cycle nor irregularity in the frequency of the cycle was sufficient alone to increase the risk of hip fracture, but that women with a history of both of these irregularities increased their risk by 82% over that of women with regular cycles.

Progesterone promotes
the remodeling and
formation of new bone.

Because this study was conducted over an 11-year period, from 1986 to 1997, and followed the progress of over 33,000 randomly recruited women, its results are probably applicable to the female population at large. The authors suggest that irregular cycles may be due to low estrogen and progesterone levels and that this condition may increase the risk of osteoporosis and postmenopausal fractures. Indeed, other researchers have demonstrated that women with irregular menstrual cycles consistently show low levels of progesterone13 and that BMD can be increased with progesterone treatment (10 days per month).

Additional Benefits of Natural Progesterone:

  • Improves premenstrual symptoms (PMS)
  • Protects against endometrial cancer
  • Helps protect against breast cancer
  • Promotes survival of the embryo and fetus throughout gestation
  • Precursor of other sex hormones (estrogen and testosterone) and cortisone
  • Maintains lining of uterus
  • Protects against fibrocystic breasts
  • Natural diuretic
  • Acts as a natural antidepressant
  • Promotes fat burning for energy (thermogenesis)
  • Aids thyroid hormone action
  • Normalizes blood clotting
  • May help maintain sex drive
  • Helps keep blood sugar levels normal

Dr. John Lee, a leading authority on natural progesterone replacement therapy, states in his book, What Your Doctor May Not Tell You About Menopause,

Postmenopausal osteoporosis is a disease of excess bone loss caused by a progesterone deficiency and secondarily a poor diet and lack of exercise. Progesterone restores bone mass. Natural progesterone hormone is an essential factor in the prevention and proper treatment of osteoporosis. . . . Whenever I see a woman bent over from osteoporosis, I wish she could have been given the benefit of natural progesterone.

Progesterone is best applied transdermally. Oral ingestion leads to extensive and variable inactivation of the compound, whereas progesterone absorbed through the skin passes into the bloodstream intact. In addition, transdermal application mimics the natural release of progesterone as it enters the bloodstream gradually and at a relatively constant rate.

Natural progesterone has a molecular structure identical to that of human progesterone. Synthetic progesterone, while very similar to the natural product, does not interact with the body in exactly the same way and therefore cannot duplicate the action of the natural compound. In addition, the synthetic forms of progesterone may cause unpleasant side effects and may even increase the risk of certain diseases, such as heart disease.

Women at risk of osteoporosis have a variety of choices available to them to stave off the debilitating effects of this disease. A lifestyle that includes appropriate calcium intake, exercise and natural progesterone is a good way to start.


  1. Baran D. Osteoporosis: efficacy and safety of a bisphosphonate dosed once weekly. Geriatrics 2001;56:28-32.
  2. National Osteoporosis Foundation. Physician's Guide to Prevention and Treatment of Osteoporosis. Belle Mead, NJ: Excerpta Medica, 1998.
  3. Vico L, Collet P, Guignandon A, et al. Effects of long-term microgravity exposure on cancellous and cortical weight-bearing bones of cosmonauts. Lancet 2000;355:1607-11.
  4. Snow CM, Shaw JM, Winters KM, Witzke KA. Long-term exercise using weighted vests prevents hip bone loss in postmenopausal women. J Geron A Biol Sci Med Sci 2000;55:M489-91.
  5. Rutherford OM. Is there a role for exercise in the prevention of osteoporotic fractures? Br J Sports Med 1999;33:378-86.
  6. Friedrich MJ. Women, exercise and aging: Strong message for the "weaker" sex. JAMA 2001;285;1429-31.
  7. Szulc P, Munoz F, Claustrat B, et al. Bioavailable estradiol may be an important determinant of osteoporosis in men: the MINOS study. J Clin Endocrinol Metab 2001;86:192-9.
  8. PEPI Writing Group. Effects of hormone therapy on bone mineral density: results from the postmenopausal estrogen/progestin interventions (PEPI) trial. JAMA 1996;276:1389-96.
  9. Prior JC. Progesterone as a bone-trophic hormone. Endocr Rev 1990;11:386-98.
  10. Lee JR. Osteoporosis reversal with transdermal progesterone. Lancet 1990;336:1327.
  11. Chiu KM, Ju J, Mayes D, Bacchetti P, Weitz S, Arnaud CD. Changes in bone resorption during the menstrual cycle. J Bone Miner Res 1999;14:609-15.
  12. Nicodemus KK, Folsom AR, Anderson KE. Menstrual history and risk of hip fractures in postmenopausal women: The Iowa Women's Health Study. Am J Epidemiol 2001;153:251-5.
  13. Prior JC, Vigna YM, Barr SI, Rexworthy C, Lentle BC. Cyclic medroxyprogesterone treatment increases bone density: a controlled trial in active women with menstrual cycle disturbances. Am J Med 1994;96:521-30.

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