Ipriflavone

What does it do? Ipriflavone is a synthetic flavonoid (isoflavone) derived from the soy compound daidzein. Ipriflavone promotes the incorporation of calcium into bone. It also inhibits bone breakdown. Many clinical studies, including numerous double-blind studies, have clearly shown that long-term treatment with ipriflavone (along with 1,000 mg supplemental calcium per day) is both safe and effective in halting bone loss in postmenopausal women or in women who have had their ovaries removed. Ipriflavone has also been found to improve bone density in cases of osteoporosis.1 2 3 4 5 6

In one study demonstrating that ipriflavone prevents bone loss, 56 recently post-menopausal women with low bone density were assigned to receive either ipriflavone (200 mg three times per day) or a placebo for two years.7 Consistent with most other studies with ipriflavone, all women also received 1,000 mg of elemental calcium daily. While vertebral (spine) bone density declined by 4.9% after two years in women taking only calcium, there was no change in bone density among woman taking ipriflavone supplementation.

Double-blind studies in women with osteoporosis have also shown positive effects. The most significant studies were performed in elderly women with a history of vertebral fractures due to osteoporosis.8 9 10 Ipriflavone therapy not only stopped bone loss, it actually increased bone density and significantly eliminated or improved vertebral fractures and bone pain.

However, one double-blind study has failed to confirm the beneficial effect of ipriflavone. In that study, ipriflavone was no more effective than a placebo for preventing bone loss in postmenopausal women with osteoporosis.11 The women in this negative study were older (average age, 63.3 years) than those in most other ipriflavone studies and had relatively severe osteoporosis. It is possible that ipriflavone works only in younger women or in those with less severe osteoporosis.

Where is it found? Ipriflavone does occur naturally in food but only in trace amounts. It is available as a nutritional supplement.

Ipriflavone has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
2Stars Osteoporosis
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Who is likely to be deficient? As ipriflavone is not an essential nutrient, no deficiency state exists.

How much is usually taken? The typical supplemental amount of ipriflavone is 200 mg three times daily. Taking 300 mg twice daily has been reported to be just as effective as 200 mg three times per day.12

Are there any side effects or interactions? In a trial of ipriflavone for osteoporosis, 29 of the 132 women in the ipriflavone group completing the three-year trial developed a clinically significant drop in lymphocytes.13 These cells, which make up approximately 22 to 28% of the white blood cells in the normal adult, are critical components of the immune system and its ability to respond to viral infections. In some of these women, a return to normal levels took almost two years after they had stopped the ipriflavone. Since this finding has been reported in one other smaller clinical trial,14 it suggests that women choosing to take ipriflavone should have their lymphocytes measured regularly by their doctor.

In double-blind studies, the frequency of perceived side effects in ipriflavone-treated people (14.5%) was actually less than that observed in people receiving the placebo (16.1%).15 Side effects were mainly mild stomach upset. Researchers recommend that patients with severe kidney disease take a lower amount of ipriflavone (200 to 400 mg daily).16

Are there any drug interactions? Certain medications may interact with ipriflavone. Refer to the drug interactions safety check for a list of those medications.

References:

1. Agnusdei D, Bufalino L. Efficacy of ipriflavone in established osteoporosis and long-term safety. Calcif Tissue Int 199:61:S23–7 [includes review].

2. Head KA. Ipriflavone: an important bone-building isoflavone. Altern Med Rev 1999;4:10–22 [review].

3. Avioli LV. The future of ipriflavone in the management of osteoporotic syndromes. Calcif Tissue Int 1997;61 Suppl 1:S33–5 [review].

4. Adami S, Bufalino L, Cervetti R, et al. Ipriflavone prevents radial bone loss in postmenopausal women with low bone mass over 2 years. Osteoporos Int 1997;7:119–25.

5. Nozaki M, Hashimoto K, Inoue Y, et al. Treatment of bone loss in oophorectomized women with a combination of ipriflavone and conjugated equine estrogen. Int J Gynaecol Obstet 1998;62:69–75.

6. Gennari C, Adami S, Agnusdei D, et al. Effect of chronic treatment with ipriflavone in postmenopausal women with low bone mass. Calcif Tissue Int 1997;61:S19–22.

7. Gennari C, Agnusdei D, Crepaldi G, et al. Effect of ipriflavone—a synthetic derivative of natural isoflavones—on bone mass loss in the early years after menopause. Menopause 1998;5:9–15.

8. Agnusdei D, Buffalino L. Efficacy of ipriflavone in established osteoporosis and long-term safety. Calcif Tissue Int 1997;61 Suppl 1:S23–7.

9. Passeri M, Biondi M, Costi D, et al. Effects of 2-year therapy with ipriflavone in elderly women with established osteoporosis. Ital J Mineral Electrolyte Metabol 1995;9:137–44.

10. Kovacs AB. Efficacy of ipriflavone in the prevention and treatment of postmenopausal osteoporosis. Agents Actions 1994;41(1–2):86–7.

11. Alexandersen P, Toussaint A, Christiansen C, et al. Ipriflavone in the treatment of postmenopausal osteoporosis: a randomized controlled trial. JAMA 2001;285:1482–8.

12. Acerbi D, Poli G, Ventura P. Comparative bioavailability of two oral formulations of ipriflavone in healthy volunteers at steady-state. Evaluation of two different dosage schemes. Eur J Drug Metabol Pharmacokinet 1998,23:172–7.

13. Alexandersen P, Toussaint A, Christiansen C, et al. Ipriflavone in the treatment of postmenopausal osteoporosis. JAMA 2001;285:1482–8.

14. Agnusdei D, Bufalino L. Efficacy of ipriflavone in established osteoporosis and long-term safety. Calcif Tissue Int 1997;61:23–27.

15. Agnusdei D, Bufalino L. Efficacy of ipriflavone in established osteoporosis and long-term safety. Calcif Tissue Int 199:61:S23–7 [includes review].

16. Rondelli I, Acerbi D, Ventura P. Steady-state pharmacokinetics of ipriflavone and its metabolites in patients with renal failure. Int J Clin Pharm Res 1991;11:183–92.