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The Role And Risk Of Ipriflavone And Ostivone In Treating Osteoporosis

Research shows that ipriflavone helps to prevent bone loss when used with sufficient calcium... but will not necessarily restore bone mineral density once it has been lost.

It should be used only under medical supervision because of interactions with various medications and the potential for lowering white blood cell levels.

Contrary to popular belief, ipriflavone is not a natural substance but is a synthetic compound derived in a laboratory from the isflavone (daidzein) taken from soy.

It is available as a prescription drug in Japan, Italy and Turkey and is also available in health food stores both on its own and as an ingredient within calcium supplements such as Ostivone. It is not an essential nutrient and is not found in food.


The chemical structure of ipriflavone is similar to that of estrogen which enables it to inhibit bone-degrading osteoclast activity... but without stimulating breast and uterine tissue or increasing the risk of cancer.


Numerous double-blind, placebo-controlled studies involving a total of over 1,700 participants have examined the effects of the supplement on various forms of osteoporosis. The studies suggest that combined with adequate calcium, it can slow the progression of osteoporosis and possibly reverse it to a limited extent while reducing the pain of fractures. For example, a 2-year, double-blind study following 198 postmenopausal women showed a gain in bone density of 1% in the supplement group and a loss of 0.7% in the placebo group.

However, the largest and longest study found no benefit from the use of the supplement. (Alexandersen P, Toussaint A, Christiansen C, et al. Ipriflavone in the treatment of postmenopausal osteoporosis: a randomized controlled trial. JAMA. 2001;285:1482-1488.) In this 3-year trial of 474 postmenopausal women, the supplement and placebo groups experienced similar results.

But unlike other studies that added 1,000 mg of calcium to participants’ supplement program, this study gave participants only 500 mg of calcium daily. Interestingly, the study also failed to provide participants with vitamin D supplements that are essential for calcium absorption.

Research shows that approximately 75% of North Americans are vitamin D deficient in the winter months. After a blood test showed that I had dropped below the acceptable range with 2,000 IUs of vitamin D, I began taking 5,000 IUs daily which now sustains me through a Canadian winter.


The most common side effect of the supplement concerns digestive complaints and occasionally diarrhea among sensitive individuals. Chiesi Pharmacy, the Italian manufacturer of the product Osteofix 200, warns that patients who are sensitive to the drug may experience skin rashes and itchiness or gastrointestinal troubles such as nausea, vomiting, gastralgia, diarrhea and dizziness.

Although most of the 3,000 people who used the supplement in clinical studies did not experience serious side effects, the largest study (the 3-year, double-blind trial of almost 500 women in Europe) reported that ipriflavone can reduce levels of white blood cells called lymphocytes thereby compromising the immune system. This is consistent with warnings provided by Chiesi Pharmacy which warns that a reduction in red and white cells has occasionally been observed.

Researchers recommend that the supplement be avoided by pregnant and lactating women and should not be used by people with:

  • Immune deficiencies such as HIV
  • Conditions requiring drugs that suppress the immune system (corticosteroids, methotrexate, or cyclosporine)
  • Severe kidney disease
  • Ulcers

There is also some evidence that combining estrogen with the supplement may increase the risk of uterine cancer and possibly breast cancer.


Ipriflavone may interfere with certain drugs by affecting the way they are processed in the liver. Studies have shown interference with the following medications:

  • Theophylline (an asthma drug)
  • Tolbutamide (a drug for diabetes)
  • Dilantin/Phenytoin (used for epilepsy)
  • Coumadin/Warfarin (a blood thinner).

The supplement may change the levels of these drugs in a patient’s body and could also raise levels of caffeine when a person drinks coffee or certain cola beverages.


The most common dosage recommendation for ipriflavone is 200 mg three times a day after meals or 300 mg twice daily. It must be combined with calcium intake of at least 1,000 mg daily and vitamin D supplements that will sustain blood levels within the recommended range throughout the winter months.

Long term treatment has not shown any accumulation of the supplement that would prove harmful and there are no known cases of an overdose.


While ipriflavone may be an option for some who are seeking a non-pharmaceutical solution to bone loss... it should only be considered after introducing a traditional supplement program that includes adequate calcium, vitamin D3, magnesium and vitamin K2.

Once this program has been stabilized, vitamin D intake should be adjusted to ensure that blood levels remain within the optimal range throughout the winter. As this program becomes part of the daily routine... strontium citrate may be assessed for inclusion in a natural bone health program.

The addition of ipriflavone may be considered when rapid bone loss persists in spite of the above program... but only under medical supervision. A white blood cell count and lymphocyte count should be taken before using the supplement and then at six months, a year and every year thereafter. (Most changes occur within the first 6-12 months or one year but a yearly check-up is wise.) Anyone who develops excessively low lymphocytes should terminate use of the supplement immediately.

Further information on how to establish a mineral and vitamin program prior to the introduction of ipriflavone... visit Osteoporosis Treatment Guidelines.