Isoflavones (soy and red clover)

Isoflavones are compounds found in soy and in red clover. Isoflavones (soy and red clover) is used for Blood cholesterol, Menopausal hot flashes and Breast cancer risk.

Pronunciation: pronunciation varies by local usage.

Generic name: isoflavones
Drug class: Dietary supplement; soy and red clover isoflavones are described in the sources as compounds structurally similar to the hormone estrogen
Form: The sources describe dietary supplements generally as coming as pills, capsules, powders, drinks, and energy bars. No product-specific dosage form for isoflavones is established by these sources.
Route: Oral use is described for herbal products intended for oral use that are marketed as dietary supplements; the sources note herbal products may also be administered topically. Product-specific route is not established by these sources.
Legal status: Marketed as a dietary supplement in the United States. Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public.

Availability and supply rules vary by country

Trade names by country:

Australia: · Full directory

What isoflavones is and how it works

Isoflavones are compounds found in soy and in red clover. The sources describe soy isoflavones and red clover isoflavones as compounds structurally similar to the hormone estrogen. Soy supplements may contain soy protein, isoflavones, or other components. Soy products and red clover dietary supplements are promoted for various health purposes, including high cholesterol, high blood pressure, diabetes, symptoms of menopause, and women's health conditions. (1) (2) (3)

This page is limited to United States government sources (NIH NCCIH and NLM MedlinePlus) accessed on 2026-10-13. Where those sources describe evidence as weak, mixed, conflicting, or insufficient, this page says so. Dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public, and manufacturers and distributors are responsible for evaluating the safety and labeling of their products before marketing. The sources advise talking with a health care provider about any complementary health approaches used, and before using soy or other herbal products if you take any type of medicine.

Mechanism of action: how isoflavones works

Not established by the sources used for this page. The sources describe soy isoflavones and red clover isoflavones as compounds structurally similar to the hormone estrogen, but do not provide pharmacokinetic or pharmacodynamic details. (1) (2) (3)

What is Isoflavones used for?

Blood cholesterol

Consuming soy protein in place of other proteins may lower cholesterol levels to a small extent; soy isoflavones may not have the same effect. For red clover, the source states red clover may have a beneficial effect on cholesterol levels in postmenopausal women, but more research is needed before definite conclusions can be reached, and findings on cholesterol levels were conflicting. (1) (2)

Menopausal hot flashes

Soy isoflavone supplements or soy protein may help to reduce the frequency and severity of menopausal hot flashes, but the effect may be small, and research results have not been completely consistent. Studies on the effects of red clover on hot flashes associated with menopause have had inconsistent results, and some of the studies had a high risk of bias. (1) (2)

Breast cancer risk

Observational studies indicate that among Asian and Asian-American women, higher dietary intakes of soy are associated with a lower risk of breast cancer; the amounts of soy in Western diets, even among the highest consumers of soy, may be too low for this association to be observed. Soy products in supplement form have not been shown to reduce breast cancer risk. (1)

Bone density

Soy isoflavones probably have a beneficial effect on bone density in postmenopausal women. For red clover, only a small number of studies have been done on the effects on bone density in postmenopausal women, and the results have been inconsistent. (1) (2)

Blood pressure

Consumption of soy isoflavones may lead to a modest decrease in blood pressure. (1)

Type 2 diabetes and blood sugar

People who consume diets high in soy may have a lower risk of type 2 diabetes. It is uncertain whether soy products improve control of blood sugar in people who already have type 2 diabetes. (1)

Cognitive function

It is uncertain whether soy has beneficial effects on cognitive function; studies have had conflicting results. (1)

Red clover overall evidence

Red clover has been studied in people, but the research has not shown conclusive evidence of benefits for any health condition. (2)

Before taking isoflavones

Do not take / not appropriate for

The sources used for this page do not state a do-not-take list for isoflavones. They advise talking with a health care provider before using soy or other herbal products if you take any type of medicine, because some herbs and medicines interact in harmful ways. (not established by these sources) (1) (2)

Tell your clinician about

Talk with your health care providers about any complementary health approaches you use, so you can make shared, well-informed decisions.
If you take any type of medicine, talk with your health care provider before using soy or other herbal products; some herbs and medicines interact in harmful ways.
Tell your health care provider about any dietary supplements you use.
Check with your health care provider about the supplements you take if you are going to have any type of surgery.
Soy allergy status: some people are allergic to soy, and in the United States the presence of soy in packaged foods and dietary supplements must be indicated on the product label.
Pregnancy and breastfeeding: the use of soy during pregnancy may be unsafe in amounts greater than those commonly found in foods, and little is known about whether it is safe to use soy in amounts greater than those commonly found in foods while breastfeeding. Red clover supplements may be unsafe for use during pregnancy or while breastfeeding.

(1) (2) (3)

Isoflavones dosage and how to take it

The sources used for this page do not provide a dose, schedule, or administration protocol for isoflavone supplements. No dose is given here because none is established by these sources.
Do not take a bigger dose than the label recommends.
Talk with your health care provider before using soy or other herbal products if you take any type of medicine.
Tell your health care provider about any dietary supplements you use, and check with your health care provider about the supplements you take if you are going to have any type of surgery.

(3) (1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3)

Missed dose

Not established by the sources used for this page. These sources do not provide missed-dose guidance for isoflavone supplements. Ask your health care provider or pharmacist for product-specific instructions.

Overdose

Not established by the sources used for this page. These sources do not state an overdose amount or overdose management for isoflavone supplements. They advise not taking a bigger dose than the label recommends, and advise talking with a health care provider about the supplements you take. Contact a health care provider or a poison control service for any suspected overdose. (3)

Isoflavones side effects

The sources used for this page state that side effects of soy may include bloating, constipation, diarrhea, and nausea. In research studies, soy protein supplements have been safely used for up to 16 weeks, and soy extracts containing concentrated isoflavones have been used safely for up to 6 months. Red clover extracts have been used in clinical studies for as long as 2 years with apparent safety, and they appear to be well tolerated. Other side effects are not established by these sources.

Bloating, constipation, diarrhea, or nausea

What to notice: Digestive symptoms listed by the source as side effects of soy.

What to do: Discuss persistent or troublesome symptoms with your health care provider. (1)

Soy allergy

What to notice: Some people are allergic to soy. In the United States, the presence of soy in packaged foods and dietary supplements must be indicated on the product label.

What to do: If you have a soy allergy, check product labels and talk with your health care provider before using soy-containing supplements. (1)

Possible interaction with monoamine oxidase inhibitors

What to notice: Interactions between certain soy products containing high amounts of tyramine (such as tofu and soy sauce) and monoamine oxidase inhibitors (a group of antidepressant drugs) have been reported, described in the source as dangerously high blood pressure.

What to do: If you take any type of medicine, talk with your health care provider before using soy or other herbal products; some herbs and medicines interact in harmful ways. Seek medical attention promptly for symptoms of dangerously high blood pressure and let the clinician you see advise on whether to continue or stop the product. (1)

Serious warnings

Soy allergy — see_clinician

Symptoms: Some people are allergic to soy.

Action: In the United States, the presence of soy in packaged foods and dietary supplements must be indicated on the product label. Talk with your health care provider about any supplement use if you have a soy allergy. (1)

Interaction with monoamine oxidase inhibitors (MAOIs) and high-tyramine soy products — see_clinician

Symptoms: Interactions between certain soy products containing high amounts of tyramine (such as tofu and soy sauce) and monoamine oxidase inhibitors (a group of antidepressant drugs) have been reported, described in the source as dangerously high blood pressure.

Action: If you take any type of medicine, talk with your health care provider before using soy or other herbal products; some herbs and medicines interact in harmful ways. Seek medical attention promptly for symptoms of dangerously high blood pressure and let the clinician you see advise on whether to continue or stop the product. (1)

Pregnancy and breastfeeding — see_clinician

Symptoms: The use of soy during pregnancy may be unsafe in amounts greater than those commonly found in foods. Little is known about whether it is safe to use soy in amounts greater than those commonly found in foods while breastfeeding. Red clover supplements may be unsafe for use during pregnancy or while breastfeeding.

Action: Talk with your health care provider before using soy or red clover supplements during pregnancy or while breastfeeding. (1) (2)

Interactions

Medicine or test	Effect	Action
Monoamine oxidase inhibitors (a group of antidepressant drugs)	Interactions between certain soy products containing high amounts of tyramine (such as tofu and soy sauce) and monoamine oxidase inhibitors have been reported (described in the source as dangerously high blood pressure).	Talk with your health care provider before using soy or other herbal products if you take any type of medicine; some herbs and medicines interact in harmful ways. (1)
Any type of medicine	The source states that if you take any type of medicine, some herbs and medicines interact in harmful ways.	Talk with your health care provider before using soy or other herbal products. (1) (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

The use of soy during pregnancy may be unsafe in amounts greater than those commonly found in foods. Red clover supplements may be unsafe for use during pregnancy. (1) (2)

Breastfeeding

Little is known about whether it is safe to use soy in amounts greater than those commonly found in foods while breastfeeding. Red clover supplements may be unsafe for use while breastfeeding. (1) (2)

Postmenopausal women

Soy isoflavones probably have a beneficial effect on bone density in postmenopausal women. Red clover may have a beneficial effect on cholesterol levels in postmenopausal women, but more research is needed before definite conclusions can be reached; only a small number of red clover studies have been done on bone density in postmenopausal women and results have been inconsistent. (1) (2)

Children

Not established by the sources used for this page. The soy source states that its fact sheet focuses on the use of soy by adults for health purposes. No pediatric guidance is provided by these sources. (1)

People having surgery

Check with your health care provider about the supplements you take if you are going to have any type of surgery. (3)

Monitoring

Before starting

Talk with your health care providers about any complementary health approaches you use, so you can make shared, well-informed decisions.
Tell your health care provider about any dietary supplements you use.
If you take any type of medicine, talk with your health care provider before using soy or other herbal products; some herbs and medicines interact in harmful ways.
Check with your health care provider about the supplements you take if you are going to have any type of surgery.
Read trustworthy information about the supplement.
If you have a soy allergy, note that in the United States the presence of soy in packaged foods and dietary supplements must be indicated on the product label.

During treatment

Do not take a bigger dose than the label recommends.
Tell your health care provider about any dietary supplements you use.
Report side effects such as bloating, constipation, diarrhea, or nausea to your health care provider, particularly if they are persistent or troublesome.

(3) (1) (2)

Storage

Not established by the sources used for this page. These sources do not provide storage instructions for soy or red clover isoflavone supplements. Follow the product label and ask your pharmacist for product-specific storage instructions.

Professional information

Clinician-facing context only. Use current product labeling and the current US NIH NCCIH and NLM MedlinePlus information. These sources describe evidence for soy and red clover as weak, mixed, conflicting, or insufficient for several uses, and dietary supplements are not FDA-approved before sale.

United States

Indication: Isoflavone supplement use

Dose summary: No dose is given by the sources used for this page. No dose is displayed here because none is established by these sources; do not invent or extrapolate a dose. Products should not be taken in a bigger dose than the label recommends.

Renal context: Not established by the sources used for this page. These sources do not provide renal impairment guidance for soy or red clover isoflavones. (3) (1) (2)

Mechanism of action

Hepatic guidance

Not established by the sources used for this page. These sources do not provide hepatic impairment guidance for soy or red clover isoflavones.

Overdose note

Not established by the sources used for this page. These sources do not state an overdose amount or overdose management for isoflavone supplements. (1) (2) (3)

Frequently asked questions

What do the sources say about how much is known about soy and red clover?

The soy source states that many studies have been conducted on the safety and usefulness of soy products, and that enough is known to conclude there are potential beneficial effects on blood cholesterol levels, menopausal hot flashes, breast cancer risk, bone density, and blood pressure, but that effects may vary for different types of soy products and in different populations. The red clover source states that red clover has been studied in people, but the research has not shown conclusive evidence of benefits for any health condition. (1) (2)

Do soy isoflavones lower cholesterol the same way soy protein does?

The source states that consuming soy protein in place of other proteins may lower cholesterol levels to a small extent, and that soy isoflavones may not have the same effect. (1)

Can soy or red clover supplements reduce breast cancer risk?

Observational studies indicate that among Asian and Asian-American women, higher dietary intakes of soy are associated with a lower risk of breast cancer, and the amounts of soy in Western diets, even among the highest consumers of soy, may be too low for this association to be observed. Soy products in supplement form have not been shown to reduce breast cancer risk. The sources do not state a breast cancer risk effect for red clover supplements. (1)

Are isoflavone supplements safe to use for a long time?

The source reports that in research studies, soy protein supplements have been safely used for up to 16 weeks, and soy extracts containing concentrated isoflavones have been used safely for up to 6 months. Red clover extracts have been used in clinical studies for as long as 2 years with apparent safety, and they appear to be well tolerated. These are research-study durations and are not a recommendation for use. (1) (2)

Can soy supplements interact with my medicines?

Interactions between certain soy products containing high amounts of tyramine (such as tofu and soy sauce) and monoamine oxidase inhibitors (a group of antidepressant drugs) have been reported, described in the source as dangerously high blood pressure. If you take any type of medicine, talk with your health care provider before using soy or other herbal products; some herbs and medicines interact in harmful ways. (1)

How are dietary supplements regulated in the United States?

Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public. Manufacturers and distributors of supplements are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all regulatory requirements. When public health concerns arise about the safety of a dietary supplement or an ingredient, the FDA can take action to protect the public. (1) (2) (3)

What is the mechanism of action of isoflavones?

What is the generic name of Isoflavones (soy and red clover)?

The generic name is isoflavones. (1) (2) (3)

What class of drug is isoflavones?

Isoflavones (soy and red clover) is classed as: Dietary supplement; soy and red clover isoflavones are described in the sources as compounds structurally similar to the hormone estrogen. (1) (2) (3)

References

Soy: Usefulness and SafetyNational Center for Complementary and Integrative Health, National Institutes of Health · United States · dated 2025-04 · accessed 2026-10-13 · source 1
Red Clover: Usefulness and SafetyNational Center for Complementary and Integrative Health, National Institutes of Health · United States · dated 2025-04 · accessed 2026-10-13 · source 2
Dietary SupplementsMedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-10-13 · source 3

Brand names by country

Single-ingredient isoflavones names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

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