Herb & supplement monograph

Ipriflavone Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Ipriflavone interacts with medications. The heart of this page is the interaction list — every drug Ipriflavone is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Ipriflavone is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Ipriflavone Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Ipriflavone drug interaction appears low for most people, though a few medicines deserve real attention. None of the listed interactions are rated major, and the vast majority rest on theoretical enzyme effects rather than problems actually seen in people.

Interactions deserving the most attention

The best-documented concern is theophylline: ipriflavone appears to slow how the body clears it, and raised theophylline levels have been reported in people who started the supplement. We also take immunosuppressants seriously, since ipriflavone has lowered certain white blood cell counts in some users, and adding that effect to a transplant or autoimmune medicine is a combination we would rather see avoided. Finally, because ipriflavone may affect an enzyme that helps clear warfarin, any change in bleeding risk with that narrow-margin drug is worth watching for.

What the rest of the list means

The long list of interacting medications looks alarming, but nearly all of it comes from one prediction, that ipriflavone might slow enzymes the body uses to process many common drugs. That idea is based on lab reasoning, not confirmed human harm, so most of these combinations have never been shown to cause real problems.

Check your medications against Ipriflavone

Based on HelloPharmacist’s Ipriflavone interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Ipriflavone

392 medications have a known interaction with Ipriflavone, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Ipriflavone using our pharmacist-reviewed interaction data.

AI summaries are generated from our Ipriflavone interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Ipriflavone combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Ipriflavone affects

Every type of medication (drug category) Ipriflavone is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 4 drug categories Ipriflavone interacts with

Cytochrome P450 1a2 (cyp1a2) SubstratesCytochrome P450 2c9 (cyp2c9) SubstratesImmunosuppressantsTheophylline

Cytochrome P450 1A2 (Cyp1A2) Substrates

Ipriflavone is thought to competitively inhibit cytochrome P450 1A2 (CYP1A2). Theoretically, concurrent use of ipriflavone and drugs metabolized by these enzymes might result in decreased drug elimination, increased serum levels, and potential toxicity. Some drugs metabolized by CYP1A2 include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), Pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline (Slo-bid, Theo-Dur, others), zileuton (Zyflo), Zolmitriptan (Zomig), and others.

Likelihood Possible Evidence D

Cytochrome P450 2C9 (Cyp2C9) Substrates

Ipriflavone is thought to competitively inhibit cytochrome P450 2C9 (CYP2C9). Theoretically, concurrent use of ipriflavone and drugs metabolized by these enzymes might result in decreased drug elimination, increased serum levels, and potential toxicity. Some drugs metabolized by CYP2C9 include amitriptyline (Elavil), diazepam (Valium), estradiol (Estrace), tacrine (Cognex), verapamil (Calan), warfarin (Coumadin), zileuton (Zyflo), and others.

Likelihood Possible Evidence D

Immunosuppressants

Concurrent use of ipriflavone and immunosuppressant drugs might have additive effects on inhibiting immune function. Some patients taking ipriflavone experience subclinical lymphocytopenia; avoid concurrent use. Immunosuppressant drugs include azathioprine (Imuran), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), muromonab-CD3 (OKT3, Orthoclone OKT3), mycophenolate (CellCept), tacrolimus (FK506, Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone), and other corticosteroids (glucocorticoids).

Likelihood Possible Evidence A

Theophylline

Concomitant use of theophylline and ipriflavone can increase serum theophylline levels. Increased theophylline levels have occurred in two cases after patients started taking ipriflavone. Ipriflavone is thought to decrease theophylline metabolism through competitive inhibition of the cytochrome P450 1A2 (CYP1A2) enzyme.

Likelihood Probable Evidence D

Monograph

Ipriflavone: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Ipriflavone is a synthetic isoflavone studied mainly for bone health and osteoporosis, but high-quality research has not shown that it reliably prevents fractures or builds strong bone. Because it can lower white blood cell counts in some people and its long-term safety is not well established, talk with your pharmacist or doctor before using it.

Part used: Synthetic compound (a semi-synthetic isoflavone derived from soy isoflavones)
Common forms: Tablets, capsules

People commonly use it for

Bone density and osteoporosis
Postmenopausal bone loss
Athletic performance
Tinnitus related to bone disorders

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

May lower white blood cell counts and has limited long-term safety data.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Ipriflavone (also called 7-isopropoxyisoflavone) is a man-made compound that is created by chemically changing an isoflavone found in soy. It is not an herb you can grow or harvest; it is made in a laboratory. Because its structure is similar to other isoflavones, it has been studied mainly for its possible effects on bones.

In some countries, ipriflavone has been sold as a prescription medicine for osteoporosis. In the United States, it is available over the counter as a dietary supplement. People most often take it in tablet or capsule form, alone or combined with calcium and vitamin D.

How it works

Ipriflavone is an isoflavone, a type of plant-based compound that is structurally similar to estrogen. In the body, it is broken down into several metabolites, some of which resemble other isoflavones.

Researchers believe it may act on bone cells by slowing the activity of osteoclasts, the cells that break down bone, while possibly supporting cells that build bone. Much of this comes from laboratory and animal research, and the way it behaves in test tubes has not translated into strong results in people.

Even though it comes from a soy isoflavone, ipriflavone itself is thought to have weak or little direct estrogen activity in the body. Its exact effects in humans are not fully understood.

Effectiveness

Does Ipriflavone work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 2 uses evaluated

2 Likely effective

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Likely Effective Osteoporosis

Rating & evidence shown verbatim from Natural Medicines

Most clinical research shows that ipriflavone can prevent loss of bone mineral density (BMD) in postmenopausal adults when taken in combination with calcium 1000 mg daily, with or without estrogen. It may also be beneficial in other patients, including oophorectomized adults and those with vitamin D deficiency.

Likely Effective Paget disease

Rating & evidence shown verbatim from Natural Medicines

There is some evidence that ipriflavone 600 mg or 1200 mg given orally for 30 days can reduce bone pain, serum alkaline phosphatase levels, and hydroxyproline/creatinine excretion in patients with Paget disease.

Sources Ref 2176

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

One important concern with ipriflavone is that some studies found it can lower the number of lymphocytes, a type of white blood cell that helps fight infection. This effect did not always recover quickly, which raises safety questions, especially with long-term use.

People with low white blood cell counts, weakened immune systems, or kidney problems should be especially cautious, since ipriflavone is processed and cleared in ways that may be affected by kidney function. If you have a bone disorder, it is far safer to use treatments that are proven to reduce fracture risk.

Pregnancy and breastfeeding: There is not enough reliable safety information, and ipriflavone has hormone-like roots. To be safe, it should be avoided during pregnancy and while breastfeeding. Always talk with your pharmacist or doctor before starting any supplement in these situations.

Side effects

Ipriflavone is usually reported as well tolerated in the short term, but side effects can occur. The most common ones involve the stomach and digestion, such as nausea, stomach upset, or diarrhea.

The most notable concern is a drop in white blood cell counts (lymphocytopenia), seen in some long-term studies. This may increase the risk of infection and is a reason to use ipriflavone only with medical supervision and regular blood monitoring if at all.

If you notice signs of infection, unusual fatigue, or other unexpected symptoms while taking ipriflavone, stop using it and contact your healthcare provider.

Ipriflavone: Reported Adverse Effects

Documented safety reports on Ipriflavone from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, ipriflavone is generally well-tolerated. However, some patients taking ipriflavone can experience epigastric pain, diarrhea, and dizziness. There is some concern that ipriflavone can cause lymphocytopenia when used for at least 6 months.

Reports by condition

Diarrhea Gastrointestinal

Orally, ipriflavone can cause epigastric pain and diarrhea in some people.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no officially established or universally agreed dietary supplement dose for ipriflavone. Doses used in research were studied for osteoporosis and are not a recommendation for general use.

If you choose to use a product, follow the directions on the label and do not exceed them. Because of the possible effect on white blood cells, it is wise to use the lowest amount for the shortest time and to check in with your pharmacist or doctor first. People considering it for bone health should also discuss adequate calcium and vitamin D intake.

Pregnancy & Breastfeeding

Ipriflavone & Pregnancy

Insufficient reliable information

Insufficient reliable information available; avoid using.

Ipriflavone & Breastfeeding

Insufficient reliable information

Insufficient reliable information available; avoid using.

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 6 references that drive our Ipriflavone monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Agnusdei D, Bufalino L. Efficacy of ipriflavone in established osteoporosis and long-term safety. Calcif Tissue Int 1997;61,Suppl 1:S23-7. PubMed
Alexandersen P, Toussaint A, Christiansen C, et al. Ipriflavone in the treatment of postmenopausal osteoporosis: A randomized controlled trial. JAMA 2001;285:1482-8.
Agnusdei D, Camporeale A, Gonnelli S, et al. Short-term treatment of Paget's disease of bone with ipriflavone. Bone Miner 1992;19 Suppl 1:S35-42. PubMed
Monostory K, Vereczkey L, Levai F, et al. Ipriflavone as an inhibitor of human cytochrome P450 enzymes. Br J Pharmacol 1998;123:605-10. PubMed
Takahashi J, Kawakatsu K, Wakayama T, Sawaoka H. Elevation of serum theophylline levels by ipriflavone in a patient with chronic obstructive pulmonary disease. Eur J Clin Pharmacol 1992;43:207-8. PubMed
Hu Q, Long C, Wu D, et al. The efficacy and safety of ipriflavone in postmenopausal women with osteopenia or osteoporosis: A systematic review and meta-analysis. Pharmacol Res. 2020;159:104860. PubMed

Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

Brand directory

Brands that make products with Ipriflavone

66 brands in our database make a supplement containing Ipriflavone.

Nature's Way 3,426 products Natures Plus 376 products NaturesPlus 370 products New Sun 518 products NewtonEverett 419 products NOW 4,981 products Nugevity 25 products Nutri-West 294 products OL Olympian Labs Incorporated 144 products ON Optimum Nutrition 249 products Ortho Molecular Products 298 products Pharmaxa Labs 32 products Prescribed Choice 38 products Protocol For Life Balance 929 products Pure Encapsulations 2,122 products Pure Essence 98 products Pure Essence Labs 13 products Purity Products 174 products Quest 74 products Radiance 52 products Radiance Select 6 products Reliv 59 products Solgar 1,940 products Source Naturals 1,780 products

Product directory

Supplement products with Ipriflavone

209 products in our database contain Ipriflavone. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Ipriflavone: Common Questions

What is Ipriflavone used for, and does it work?

People use Ipriflavone for many reasons, but the evidence varies by use. According to the Natural Medicines database, there is at least some clinical evidence supporting Ipriflavone for Osteoporosis and Paget disease. For most other uses it has been studied for, the evidence is currently insufficient to rate. See the graded list on this page, and always confirm with your pharmacist or doctor.

Does Ipriflavone interact with prescription medications?

Yes. We list 392 medications with a known interaction with Ipriflavone. Use the checker above to see how Ipriflavone interacts with a specific drug.

How are Ipriflavone interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Ipriflavone with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Ipriflavone interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Ipriflavone used for?

It is most often used in the hope of supporting bone health and slowing bone loss, such as in osteoporosis. However, good-quality studies have not shown it reliably prevents fractures or builds bone.

Does Ipriflavone actually work for osteoporosis?

The strongest research has been disappointing and has not confirmed a real benefit for bone density or fracture prevention. Proven osteoporosis treatments are a better choice; talk to your doctor.

Is Ipriflavone safe to take?

It may be tolerated short-term, but some studies found it can lower white blood cell counts, and long-term safety is not well established. Use it only with guidance from your pharmacist or doctor.

Can I take Ipriflavone if I am pregnant or breastfeeding?

No. There is not enough safety information and it has hormone-like origins, so it should be avoided during pregnancy and breastfeeding.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Keep exploring

Products that contain Ipriflavone

A rotating sample of real supplements in our database that list Ipriflavone — open any to see its full ingredients and every drug interaction we check.

See all 209 products with Ipriflavone →

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Ipriflavone Drug Interactions, Uses, Effectiveness, Safety & More

Your Choice:

Ipriflavone Drug Interactions: The Bottom Line

Drugs that interact with Ipriflavone

Don’t want to scroll the list? Just ask.

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Likelihood — How Well It’s Documented

Where This Data Comes From

The kinds of drugs Ipriflavone affects

Ipriflavone: Uses, Safety & Side Effects

Overview

How it works

Does Ipriflavone work?

Safety & precautions

Side effects

Ipriflavone: Reported Adverse Effects

Dosing

Ipriflavone & Pregnancy

Ipriflavone & Breastfeeding

References & further reading

Brands that make products with Ipriflavone

Supplement products with Ipriflavone

Ipriflavone: Common Questions

Related supplements & herbs

Products that contain Ipriflavone

Have a question about Ipriflavone?