Home Ingredients Biochanin A (Red Clover Isoflavone)

Biochanin A (Red Clover Isoflavone)

Evidence Level
Preliminary
6 Clinical Trials
6 Documented Benefits
1/5 Evidence Score

Biochanin A is an isoflavone, a plant compound with weak estrogen-like activity, found mainly in red clover and also in chickpeas, especially sprouted ones. Chemically it is a methylated form of genistein, and in people it is rapidly demethylated to genistein, so much of its activity in the body is likely carried by genistein and its conjugates. Isolated biochanin A has not been tested in published human trials. The human data come from red clover isoflavone mixtures that also contain formononetin, genistein and daidzein: one mixture enriched in biochanin A lowered LDL cholesterol in men but not women over 6 weeks, and a red clover extract supplying 26 mg/day of biochanin A slowed spinal bone loss in one 12-month trial without raising breast density. Most other findings come from cell and animal studies.

Studied Dose Only red clover mixtures have been tested: 26 mg/day biochanin A (43.5 mg/day total isoflavones) for 12 months, and a biochanin-enriched mixture at 40 mg/day for 6 weeks (a companion report on the same trial states 80 mg/day).
Active Compound Biochanin A (5,7-dihydroxy-4'-methoxyisoflavone), the 4'-O-methyl form of genistein; in supplements it is usually part of a red clover isoflavone extract.

Benefits

Converted to genistein in the body

In human pharmacokinetic studies, biochanin A from a supplement was rapidly and efficiently demethylated, raising blood genistein to levels similar to those after soy foods. Human liver enzymes perform this conversion in the lab. Much of its effect in the body may therefore come from genistein, although in cell studies biochanin A itself blocked aromatase and genistein did not.

Supported by Trial 5

LDL cholesterol with a biochanin-enriched red clover isoflavone mixture

In a placebo-controlled crossover trial in 46 middle-aged men and 34 postmenopausal women, a red clover isoflavone mixture enriched in biochanin A (40 mg/day for 6 weeks) lowered LDL cholesterol in men by about 9.5% versus placebo. Women did not respond, other blood lipids did not change, and the maker supplied the tablets. It is a single trial.

Supported by Trial 1

Arterial stiffness in the same biochanin-enriched trial

In the same trial, isoflavones as a group improved measures of arterial stiffness versus placebo, but the improvement seemed limited to the formononetin-enriched mixture, not the biochanin-enriched one. Neither mixture changed blood pressure or flow-mediated dilation.

Supported by Trial 2

Spinal bone density in a red clover extract rich in biochanin A

In a 12-month trial in 205 women aged 49 to 65, a red clover extract supplying 26 mg/day of biochanin A plus smaller amounts of formononetin, genistein and daidzein reduced lumbar spine bone loss versus placebo. There was no effect at the hip, and the result tests the extract, not biochanin A alone.

Supported by Trial 3, Trial 4

Hot flash frequency in red clover extracts with more biochanin A

A meta-analysis of 8 red clover extract trials found about 1.7 fewer hot flushes a day than placebo, with clearer differences when formulas had a higher share of biochanin A. Trials varied widely, and the North American Menopause Society's nonhormone therapy position statement does not recommend herbal supplements for hot flashes.

Supported by Trial 4, Trial 5

Estrogen receptor beta and aromatase activity in lab and animal studies

In rats, oral biochanin A, which the authors describe as an estrogen receptor beta agonist, reduced artery wall thickening after injury without growing the uterus. In breast cell lines it inhibited aromatase, the enzyme that makes estrogen. These are cell and rat results (the rats received 100 mg/kg) and have not been tested in people.

Supported by Trial 4, Trial 5

Mechanism of action

1

A methylated precursor of genistein

Biochanin A carries a methyl group on the 4' position of genistein. Liver enzymes (CYP1A2, 2E1, 2C9, 2C19 and 2D6 in laboratory tests) and possibly gut bacteria remove it, producing genistein; in people this happens rapidly after a dose. Reduced metabolites such as dihydrobiochanin A also appear in urine after red clover supplements.

2

Low bioavailability of the parent compound

In rats, less than 4% of an oral dose of biochanin A or genistein reached the blood unchanged, and most circulated as conjugates. In women taking red clover, isoflavones in serum were mainly conjugated metabolites. Biochanin A also dissolves poorly in water, which limits absorption.

3

Weak estrogen receptor activity

Like genistein, biochanin A binds estrogen receptors, and a rat study describes it as selective for the beta subtype, and it inhibited the estrogen-making enzyme aromatase in cell studies. Whether these effects matter at supplement doses in people has not been shown.

Clinical trials

1
Biochanin-Enriched vs Formononetin-Enriched Red Clover Isoflavones: LDL Cholesterol
PubMed

Randomized, double-blind, placebo-controlled trial with two parallel groups, each crossing over between an enriched red clover isoflavone mixture (40 mg/day) and placebo for 6 weeks per period; the maker supplied tablets and partial support (Nestel et al. 2004, Eur J Clin Nutr)

80 free-living volunteers: 46 middle-aged men and 34 postmenopausal women; 40 took the biochanin-enriched mixture and 40 the formononetin-enriched mixture.

Only the biochanin-enriched mixture lowered LDL cholesterol, and only in men: median 3.61 mmol/L on the mixture versus 3.99 mmol/L on placebo, a 9.5% difference (p<0.05). Women did not respond, and no other blood lipid changed. This is a red clover isoflavone mixture, not pure biochanin A, and it is a single trial.

2
Same Trial, Vascular Outcomes: Arterial Stiffness and Blood Pressure
PubMed

Randomized, double-blind trial of red clover isoflavones enriched in biochanin A or formononetin, crossed over with placebo in two 6-week periods (Teede et al. 2003, Arterioscler Thromb Vasc Biol)

80 healthy men and women aged 45 to 75 (46 men, 34 women). The group, design and authors match the LDL paper above; this paper states the dose as 80 mg/day, while the LDL paper states 40 mg/day.

Isoflavones as a whole improved systemic arterial compliance (p=0.04) and central pulse wave velocity (p=0.02) versus placebo, but the improvement seemed limited to the formononetin-enriched mixture (adjusted p=0.06). Neither mixture changed 24-hour blood pressure or flow-mediated dilation. The biochanin-enriched mixture did not show a clear vascular effect.

3
Red Clover Extract with 26 mg/day Biochanin A: 12-Month Bone Density Trial
PubMed

Double-blind, randomized, placebo-controlled trial of a red clover isoflavone supplement for 12 months (Atkinson et al. 2004, Am J Clin Nutr)

205 women aged 49 to 65 (177 completed). Daily dose: 26 mg biochanin A, 16 mg formononetin, 1 mg genistein and 0.5 mg daidzein.

Lumbar spine bone mineral content and density fell less than with placebo (p=0.04 and p=0.03). There was no effect at the hip or on bone resorption markers; bone formation markers rose in postmenopausal women. A red clover extract trial in which biochanin A was the largest isoflavone, not a test of biochanin A alone.

4
Same Red Clover Extract: Breast Density and Hormones (Safety)
PubMed

Double-blind, randomized, placebo-controlled trial of the same red clover isoflavone tablet for 12 months (Atkinson et al. 2004, Breast Cancer Res)

205 women aged 49 to 65 with dense mammographic patterns (177 completed); 26 mg biochanin A per day within the tablet.

Mammographic breast density fell in both groups with no significant difference between groups. There was no treatment effect on estradiol, FSH or LH (measured in postmenopausal women only) and no effect on hot flushes or other menopausal symptoms, which were low at baseline. Response differed by an estrogen receptor (ESR1) gene variant: in women with the TT genotype, estimated density rose 1.4% on isoflavones and fell 9.6% on placebo. Overall a reassuring safety result for this extract over one year, not a benefit.

5
Human Pharmacokinetics: Biochanin A Is Demethylated to Genistein
PubMed

Human pharmacokinetic studies of pure isoflavones and of commercial phytoestrogen supplements, with a content analysis of 33 products (Setchell et al. 2001, J Nutr)

Healthy adults; the pure-isoflavone part studied 19 healthy women. Biochanin A came from one phytoestrogen supplement.

Biochanin A and formononetin were rapidly and efficiently demethylated, producing high blood levels of genistein and daidzein, similar to those seen after soy foods. The 33 supplements and extracts analyzed showed considerable differences between measured and labeled isoflavone content.

6
Red Clover Supplement and Drug-Metabolizing Enzymes in Women
PubMed

Pharmacokinetic interaction study before and after 2 weeks of a standardized red clover supplement (120 mg isoflavones per day) (Chen et al. 2020, J Agric Food Chem)

15 peri- and postmenopausal women.

Blood levels over 96 hours of caffeine, tolbutamide, dextromethorphan and alprazolam (probes for CYP1A2, CYP2C9, CYP2D6 and CYP3A4/5) did not change after red clover, including in subgroups by BMI, menopausal status, race and age. The isoflavones were found in serum mainly as conjugated metabolites. Small and short; other drugs were not tested.

Side effects and drug interactions

Common Potential side effects

Safety data for isolated biochanin A in people are lacking; safety information comes from red clover isoflavone extracts.
A red clover extract supplying 26 mg/day of biochanin A for 12 months did not increase mammographic breast density versus placebo in women aged 49 to 65, and did not change estradiol, FSH or LH in the postmenopausal women in whom they were measured.
Pregnancy and breastfeeding: avoid concentrated isoflavone supplements, because of their estrogen-like activity.
Hormone-sensitive conditions, including a history of breast or uterine cancer: talk to your doctor before use.
Label accuracy varies: an analysis of 33 phytoestrogen supplements found considerable differences between measured and claimed isoflavone content.
Allergy to red clover, chickpeas or other legumes is possible.

Important Drug interactions

Tamoxifen and aromatase inhibitors: biochanin A has estrogen-like activity and inhibited aromatase in cell studies; do not combine without your oncologist's advice.
Hormone therapy and birth control pills: estrogen-like effects may add to or interfere with them; ask your doctor.
Drugs processed by liver CYP enzymes: a red clover supplement (120 mg isoflavones per day for 2 weeks) did not change blood levels of probe drugs for CYP1A2, CYP2C9, CYP2D6 and CYP3A4/5 in 15 women, but other drugs and isolated biochanin A have not been tested; ask your pharmacist about narrow-margin drugs.

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Frequently asked questions about Biochanin A (Red Clover Isoflavone)

What is biochanin A?

Biochanin A is an isoflavone, a plant compound with weak estrogen-like activity. It is found mainly in red clover and in chickpeas, especially sprouted chickpeas. In the body it is converted to genistein, the main soy isoflavone.

How is biochanin A different from red clover and genistein?

Red clover is the whole herb, and its extracts contain several isoflavones, mainly biochanin A and formononetin. Genistein is what biochanin A becomes after the body removes its methyl group. Most supplements that list biochanin A are red clover extracts, so their effects reflect the whole mixture.

Has biochanin A been tested on its own in people?

Not in published trials. Human studies used red clover isoflavone mixtures, including one enriched in biochanin A that lowered LDL cholesterol in men over 6 weeks, plus studies tracking how the body absorbs and converts it. Effects of the pure compound come from cell and animal studies.

How much biochanin A is used?

Red clover trials supplied about 26 mg/day of biochanin A within a 43.5 mg/day isoflavone extract, or a biochanin-enriched mixture at 40 mg/day (80 mg/day in a companion report on the same trial). No dose of pure biochanin A has been established. Follow the product label and check how much biochanin A it actually lists.

Is biochanin A safe for people with hormone-sensitive conditions?

Because it acts weakly like estrogen and becomes genistein, anyone with a history of hormone-sensitive cancer, or taking tamoxifen, an aromatase inhibitor or hormone therapy, should talk to their doctor first. A one-year red clover trial found no increase in breast density, but long-term data are limited.

What is Biochanin A used for?

Biochanin A has several researched uses. In human pharmacokinetic studies, biochanin A from a supplement was rapidly and efficiently demethylated, raising blood genistein to levels similar to those after soy foods. Human liver enzymes perform this conversion in the lab.

What is the recommended dosage of Biochanin A?

The clinically studied dose is Only red clover mixtures have been tested: 26 mg/day biochanin A (43.5 mg/day total isoflavones) for 12 months, and a biochanin-enriched mixture at 40 mg/day for 6 weeks (a companion report on the same trial states 80 mg/day). Always follow the product label and check with a healthcare provider for personal advice.

Is Biochanin A safe, and does it have side effects?

Side effects and cautions reported for Biochanin A include: Safety data for isolated biochanin A in people are lacking; safety information comes from red clover isoflavone extracts. A red clover extract supplying 26 mg/day of biochanin A for 12 months did not increase mammographic breast density versus placebo in women aged 49 to 65, and… It may also interact with some medications. Biochanin A is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Biochanin A interact with any medications?

Possible interactions include: Tamoxifen and aromatase inhibitors: biochanin A has estrogen-like activity and inhibited aromatase in cell studies; do not combine without your oncologist's advice. Hormone therapy and birth control pills: estrogen-like effects may add to or interfere with them; ask your doctor. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Biochanin A?

NutraSmarts rates the evidence for Biochanin A as Preliminary (1 out of 5). It is backed by 6 clinical trials and 16 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(16 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Nestel P, Cehun M, Chronopoulos A, DaSilva L, Teede H, McGrath B. A biochanin-enriched isoflavone from red clover lowers LDL cholesterol in men. Eur J Clin Nutr. 2004;58(3):403-8. doi: 10.1038/sj.ejcn.1601796.PubMedUsed to support: Randomized, double-blind, placebo-controlled trial in 46 middle-aged men and 34 postmenopausal women. Two red clover isoflavone mixtures, one enriched in biochanin A and one in formononetin, were each given at 40 mg/day (the companion vascular report on the same 80 people, Teede 2003, states 80 mg/day) for 6 weeks in a crossover against placebo. Only the biochanin-enriched mixture lowered LDL cholesterol, and only in men (9.5% versus placebo); women did not respond and no other lipid changed. Novogen, the supplement maker, provided tablets and partial support.
  2. Teede HJ, McGrath BP, DeSilva L, Cehun M, Fassoulakis A, Nestel PJ. Isoflavones reduce arterial stiffness: a placebo-controlled study in men and postmenopausal women. Arterioscler Thromb Vasc Biol. 2003;23(6):1066-71. doi: 10.1161/01.ATV.0000072967.97296.4A.PubMedUsed to support: Randomized, double-blind trial in 80 healthy people (46 men, 34 women, aged 45 to 75) given red clover isoflavones enriched in either biochanin A or formononetin (stated as 80 mg/day) crossed over with placebo for 6 weeks each. Isoflavones as a whole improved systemic arterial compliance and pulse wave velocity, but the improvement seemed limited to the formononetin-enriched mixture. Blood pressure and flow-mediated dilation did not change.
  3. Atkinson C, Compston JE, Day NE, Dowsett M, Bingham SA. The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr. 2004;79(2):326-33. doi: 10.1093/ajcn/79.2.326.PubMedUsed to support: 12-month randomized, placebo-controlled trial in 205 women aged 49 to 65 (177 completed) of a red clover isoflavone supplement supplying 26 mg biochanin A, 16 mg formononetin, 1 mg genistein and 0.5 mg daidzein per day. Lumbar spine bone loss was smaller than with placebo (p=0.03 for density); there was no effect at the hip or on bone resorption markers.
  4. Atkinson C, Warren RM, Sala E, Dowsett M, Dunning AM, Healey CS, Runswick S, Day NE, Bingham SA. Red-clover-derived isoflavones and mammographic breast density: a double-blind, randomized, placebo-controlled trial [ISRCTN42940165]. Breast Cancer Res. 2004;6(3):R170-9. doi: 10.1186/bcr773.PubMedUsed to support: Same 205-woman, 12-month trial and same supplement (26 mg biochanin A per day). Mammographic breast density fell in both groups with no significant difference between the isoflavone and placebo groups. There was no effect on estradiol, FSH or LH (measured in postmenopausal women only), and no effect on hot flushes or other menopausal symptoms, which were low at baseline. A significant interaction between treatment and an estrogen receptor (ESR1) gene variant was reported for the change in breast density.
  5. Setchell KD, Brown NM, Desai P, Zimmer-Nechemias L, Wolfe BE, Brashear WT, Kirschner AS, Cassidy A, Heubi JE. Bioavailability of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements. J Nutr. 2001;131(4 Suppl):1362S-75S. doi: 10.1093/jn/131.4.1362S.PubMedUsed to support: Human pharmacokinetic work on isoflavones. Biochanin A and formononetin from a phytoestrogen supplement were rapidly and efficiently demethylated in people, giving high blood levels of genistein and daidzein like those seen after eating soy foods. An analysis of 33 phytoestrogen supplements and extracts found considerable differences between measured and claimed isoflavone content.
  6. Chen L, Choi J, Leonard SW, Banuvar S, Barengolts E, Viana M, Chen SN, Pauli GF, Bolton JL, van Breemen RB. No Clinically Relevant Pharmacokinetic Interactions of a Red Clover Dietary Supplement with Cytochrome P450 Enzymes in Women. J Agric Food Chem. 2020;68(47):13929-13939. doi: 10.1021/acs.jafc.0c05856.PubMedUsed to support: 15 peri- and postmenopausal women took a standardized red clover supplement (120 mg isoflavones per day, including biochanin A) for 2 weeks. Blood levels of four probe drugs for CYP1A2, CYP2C9, CYP2D6 and CYP3A4/5 (caffeine, tolbutamide, dextromethorphan, alprazolam) did not change. Red clover isoflavones appeared in serum mainly as conjugated metabolites.
  7. Tsunoda N, Pomeroy S, Nestel P. Absorption in humans of isoflavones from soy and red clover is similar. J Nutr. 2002;132(8):2199-201. doi: 10.1093/jn/132.8.2199.PubMedUsed to support: Randomized crossover study in 14 people who ate a breakfast cereal with soy isoflavones or red clover isoflavones (mainly formononetin and biochanin A) for 2 weeks each. About 25% of each isoflavone was recovered in urine with either source, suggesting similar absorption. Variation between people was high.
  8. Heinonen SM, Wähälä K, Adlercreutz H. Identification of urinary metabolites of the red clover isoflavones formononetin and biochanin A in human subjects. J Agric Food Chem. 2004;52(22):6802-9. doi: 10.1021/jf0492767.PubMedUsed to support: Seven women took four red clover supplements, and the metabolites in their urine were identified. Reduced metabolites of biochanin A (dihydrobiochanin A and 6'-hydroxyangolensin) were found, and possible metabolic pathways were proposed.
  9. Tolleson WH, Doerge DR, Churchwell MI, Marques MM, Roberts DW. Metabolism of biochanin A and formononetin by human liver microsomes in vitro. J Agric Food Chem. 2002;50(17):4783-90. doi: 10.1021/jf025549r.PubMedUsed to support: Laboratory study with human liver enzymes. Biochanin A was converted to genistein by 4'-O-demethylation, catalyzed by the cytochrome P450 enzymes 1A2, 2E1, 2C9, 2C19 and 2D6. The authors conclude that the liver, not only gut bacteria, can turn these methylated isoflavones into more potent phytoestrogens.
  10. Kanadys W, Barańska A, Błaszczuk A, Polz-Dacewicz M, Drop B, Kanecki K, Malm M. Evaluation of Clinical Meaningfulness of Red Clover (Trifolium pratense L.) Extract to Relieve Hot Flushes and Menopausal Symptoms in Peri- and Post-Menopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2021;13(4):1258. doi: 10.3390/nu13041258.PubMedUsed to support: Meta-analysis of 8 red clover extract trials (10 comparisons). Hot flushes fell by a weighted mean of 1.73 per day versus placebo (p=0.029). Differences were clearer in postmenopausal women with at least 5 flushes a day, at 12 weeks, at 80 mg/day or more, and when formulas contained a higher proportion of biochanin A. The authors call for further well-designed trials.
  11. North American Menopause Society. The 2023 nonhormone therapy position statement of The North American Menopause Society. Menopause. 2023;30(6):573-590. doi: 10.1097/GME.0000000000002200.PubMedUsed to support: Position statement on nonhormone options for hot flashes, based on an expert panel review. Supplements and herbal remedies were listed as not recommended (Levels I to II), as were soy foods and soy extracts. Cited here from the published abstract.
  12. Wang Y, Man Gho W, Chan FL, Chen S, Leung LK. The red clover (Trifolium pratense) isoflavone biochanin A inhibits aromatase activity and expression. Br J Nutr. 2008;99(2):303-10. doi: 10.1017/S0007114507811974.PubMedUsed to support: Cell study. Biochanin A inhibited aromatase (CYP19), the enzyme that makes estrogen from androgens, and reduced its gene expression in breast cancer cell lines. Genistein did not inhibit the enzyme itself. Laboratory findings only.
  13. Schrepfer S, Deuse T, Münzel T, Schäfer H, Braendle W, Reichenspurner H. The selective estrogen receptor-beta agonist biochanin A shows vasculoprotective effects without uterotrophic activity. Menopause. 2006;13(3):489-99. doi: 10.1097/01.gme.0000185941.63497.10.PubMedUsed to support: Rat and cell study. Oral biochanin A (100 mg/kg) reduced thickening of the artery lining after balloon injury and improved vessel relaxation without increasing uterus growth, while ethinylestradiol did increase uterus growth. Animal findings only.
  14. Moon YJ, Sagawa K, Frederick K, Zhang S, Morris ME. Pharmacokinetics and bioavailability of the isoflavone biochanin A in rats. AAPS J. 2006;8(3):E433-42. doi: 10.1208/aapsj080351.PubMedUsed to support: Rat study. Oral biochanin A was metabolized to genistein and to conjugates of both compounds; the bioavailability of biochanin A and genistein was poor (under 4%), with signs of recycling between liver and gut. Animal findings only.
  15. Yu C, Zhang P, Lou L, Wang Y. Perspectives Regarding the Role of Biochanin A in Humans. Front Pharmacol. 2019;10:793. doi: 10.3389/fphar.2019.00793.PubMedUsed to support: Narrative review. Biochanin A is found mainly in red clover, has poor solubility and oral absorption, and is a main ingredient in many supplements for postmenopausal symptoms. The authors state its activity has not been adequately evaluated in humans and that most evidence comes from cell and animal studies.
  16. Wu Z, Song L, Feng S, Liu Y, He G, Yioe Y, Liu SQ, Huang D. Germination dramatically increases isoflavonoid content and diversity in chickpea (Cicer arietinum L.) seeds. J Agric Food Chem. 2012;60(35):8606-15. doi: 10.1021/jf3021514.PubMedUsed to support: Food chemistry study. Germination raised the isoflavone content of chickpea seeds more than 100-fold, mainly as formononetin and biochanin A, which were isolated from the sprouted seeds.