Ipriflavone for Osteoporosis
By Steven Bratman, M.D.
For the last several years, natural treatments with
good evidence behind them have been the subject of major media exposure.
St. John's wort, ginkgo, and saw palmetto are among the most well
known. The evidence that these treatments really work has become
so strong that even mainstream medicine now takes them seriously.
Sooner or later, the media will run out of proven
natural treatments to write stories about at least until further
research identifies others. But there is one dietary supplement
with great evidence behind it that still remains to be popularized:
ipriflavone. The science behind this treatment for osteoporosis
is truly impressive. However, most people haven't heard of it yet.
Ipriflavone is related to substances found in soybeans
called phytoestrogens. These chemicals act somewhat like estrogen.
Ipriflavone also acts like estrogen, but only in one specific way:
it keeps bones strong. Unlike estrogen, ipriflavone does not appear
to affect breast and uterine tissue.
This is ipriflavone's significant potential advantage
over estrogen. Estrogen increases the risk of uterine and breast
cancer, however, ipriflavone probably does not.
Numerous double-blind placebo-controlled studies
involving a total of more than 1,300 participants show that ipriflavone
can slow the progression of osteoporosis, and perhaps even reverse
it to some extent.
For example, a 2-year double-blind study followed
198 postmenopausal women who showed evidence of bone loss. At the
end of the study, there was a gain in bone density in the ipriflavone
group, while people in the placebo group lost bone mass. Numerous
other studies have found similar results.
A recently published study shows that ipriflavone
is even effective during the first couple of years following menopause,
the period of most rapid bone loss for women. In this double-blind
trial of 60 women in early menopause, treatment with ipriflavone
substantially prevented loss of bone in the spine, as compared to
treatment with calcium supplements. (Calcium supplements can help
slow bone loss, but not effectively enough to protect the spine
during the first few years after menopause.)
In addition, this study provides evidence on how
ipriflavone works to prevent osteoporosis. The body is always remodeling
bone, simultaneously building it up and breaking it down. It appears
that ipriflavone mainly works by slowing down the bone breakdown
part of this equation (as does estrogen and most medical therapies
for osteoporosis). The net result is preservation of bone mass against
the forces leading to osteoporosis.
Dosage and Safety
The usual dose of ipriflavone is 200 mg 3 times
daily, or 300 mg twice daily.
Thousands of people have used ipriflavone in clinical
studies, with no more side effects than the participants taking
placebo. However, there are some potential risks with this generally
Ipriflavone can interfere with certain drugs by
affecting the way they are processed in the liver. For example,
it could raise blood levels of the asthma drug theophylline. It
could also raise levels of caffeine and theobromine (a chemical
in chocolate). This means that if you drink coffee or eat chocolate
while taking the supplement, you might feel stronger effects than
you expect. Ipriflavone might also interact with oral diabetes medications.
Additionally, ipriflavone could interact with phenytoin
(used for epilepsy) and warfarin (a blood thinner). This is a worrisome
issue since phenytoin and warfarin cause osteoporosis, and some
people on those drugs might be tempted to take ipriflavone at the
same time to protect their bones, leading to potentially dangerous
Finally, because ipriflavone is metabolized by the
kidneys, individuals with severe kidney disease should have their
ipriflavone dosage monitored by a physician
What about Bodybuilding?
Ipriflavone is sometimes marketed for bodybuilding
and other sports uses, but there is no evidence at all that it works
for these purposes.
For more information, see Ipriflavone and Osteoporosis.
Agnusdei D, Crepaldi G, Isaia G, et al. A double-blind,
placebo-controlled trial of ipriflavone for prevention of postmenopausal
spinal bone loss. Calcif Tissue Int. 1997;61:142,147.
Ohta H, Komukai S, Makita K, et al. Effects of 1-year
ipriflavone treatment on lumbar bone mineral density and bone metabolic
markers in postmenopausal women with low bone mass. Horm Res. 1999;51(4):178,183.
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