Soy Isoflavones

Last Updated: October 24 2021

Soy Isoflavones, usually Genistein and Daidzein, are bioflavonoids found in soy products and other plants that are able to interact with various hormones such as estrogen. They appear to be healthy, and are not anathema to young men and testosterone levels.


Soy isoflavones (Genistein and Daidzein) are compounds found in a wide variety of foods, but mostly soy, that affect a wide-variety of body systems. They seem to mimic the female hormone estrogen to a degree (although slightly different).

They have been implicated in both reductions and increases of breast cancer risk, and generally are good at cardioprotection from reducing lipoprotein levels and are seen as good for bone health in the aging as well.

What else is Soy Isoflavones known as?
Note that Soy Isoflavones is also known as:
  • Genistein
  • Genistin
  • Daidzein
  • Daidzin
  • Equol
  • Dihydrogenistein
  • Dihydroglycitein
  • Glycitein
  • Glycitin
Soy Isoflavones should not be confused with:
  • Soy (the food product)
  • Soy Lecithin (another molecule found in soy)
Dosage information

Many anti-carcinogenic effects of genistein are seen in the range of 10-20mg/kg bodyweight a day. Epidemiologically, this dose is also associated with reduced lipoprotein levels.

In vitro studies on glucose and muscle cell metabolism showing a nutrient partitioning effect at 20-30uM correlate to a dietary intake of 200-300mg/kg bodyweight (assuming the 1uM circulating serum levels per 10mg/kg BW intake noted.[74])

3.^Fukutake M, Takahashi M, Ishida K, Kawamura H, Sugimura T, Wakabayashi KQuantification of genistein and genistin in soybeans and soybean productsFood Chem Toxicol.(1996 May)
6.^Alekel DL, Germain AS, Peterson CT, Hanson KB, Stewart JW, Toda TIsoflavone-rich soy protein isolate attenuates bone loss in the lumbar spine of perimenopausal womenAm J Clin Nutr.(2000 Sep)
8.^Meeran SM, Ahmed A, Tollefsbol TOEpigenetic targets of bioactive dietary components for cancer prevention and therapyClin Epigenetics.(2010 Dec 1)
11.^Saeed IA, Ali L, Jabeen A, Khasawneh M, Rizvi TA, Ashraf SSEstrogenic activities of ten medicinal herbs from the Middle EastJ Chromatogr Sci.(2013 Jan)
14.^Barnes S, Prasain J, D'Alessandro T, Arabshahi A, Botting N, Lila MA, Jackson G, Janle EM, Weaver CMThe metabolism and analysis of isoflavones and other dietary polyphenols in foods and biological systemsFood Funct.(2011 May)
15.^Day AJ, Cañada FJ, Díaz JC, Kroon PA, Mclauchlan R, Faulds CB, Plumb GW, Morgan MR, Williamson GDietary flavonoid and isoflavone glycosides are hydrolysed by the lactase site of lactase phlorizin hydrolaseFEBS Lett.(2000 Feb 25)
16.^Esaki H, Shirasaki T, Yamashita K, Nakamura Y, Kawakishi S, Osawa TAbsorption and excretion of the 8-hydroxydaidzein in rats after oral administration and its antioxidant effectJ Nutr Sci Vitaminol (Tokyo).(2005 Apr)
17.^Ahmed AA, Goldsmith J, Fokt I, Le XF, Krzysko KA, Lesyng B, Bast RC Jr, Priebe WA genistein derivative, ITB-301, induces microtubule depolymerization and mitotic arrest in multidrug-resistant ovarian cancerCancer Chemother Pharmacol.(2011 Oct)
26.^Simpson ERAromatase: biologic relevance of tissue-specific expressionSemin Reprod Med.(2004 Feb)
27.^Khan SI, Zhao J, Khan IA, Walker LA, Dasmahapatra AKPotential utility of natural products as regulators of breast cancer-associated aromatase promotersReprod Biol Endocrinol.(2011 Jun 21)
29.^Means GD, Mahendroo MS, Corbin CJ, Mathis JM, Powell FE, Mendelson CR, Simpson ERStructural analysis of the gene encoding human aromatase cytochrome P-450, the enzyme responsible for estrogen biosynthesisJ Biol Chem.(1989 Nov 15)
30.^Bulun SE, Simpson ERAromatase expression in women's cancersAdv Exp Med Biol.(2008)
33.^Chen D, Reierstad S, Lu M, Lin Z, Ishikawa H, Bulun SERegulation of breast cancer-associated aromatase promotersCancer Lett.(2009 Jan 8)
34.^Simpson ER, Michael MD, Agarwal VR, Hinshelwood MM, Bulun SE, Zhao YCytochromes P450 11: expression of the CYP19 (aromatase) gene: an unusual case of alternative promoter usageFASEB J.(1997 Jan)
36.^Bulun SE, Takayama K, Suzuki T, Sasano H, Yilmaz B, Sebastian SOrganization of the human aromatase p450 (CYP19) geneSemin Reprod Med.(2004 Feb)
37.^Sanderson JT, Hordijk J, Denison MS, Springsteel MF, Nantz MH, van den Berg MInduction and inhibition of aromatase (CYP19) activity by natural and synthetic flavonoid compounds in H295R human adrenocortical carcinoma cellsToxicol Sci.(2004 Nov)
40.^Du M, Yang X, Hartman JA, Cooke PS, Doerge DR, Ju YH, Helferich WGLow-dose dietary genistein negates the therapeutic effect of tamoxifen in athymic nude miceCarcinogenesis.(2012 Jan 20)
41.^Pelissero C, Lenczowski MJ, Chinzi D, Davail-Cuisset B, Sumpter JP, Fostier AEffects of flavonoids on aromatase activity, an in vitro studyJ Steroid Biochem Mol Biol.(1996 Feb)
42.^Kim YW, Hackett JC, Brueggemeier RWSynthesis and aromatase inhibitory activity of novel pyridine-containing isoflavonesJ Med Chem.(2004 Jul 29)
44.^Ye L, Chan MY, Leung LKThe soy isoflavone genistein induces estrogen synthesis in an extragonadal pathwayMol Cell Endocrinol.(2009 Apr 10)
46.^Ofir R, Tamir S, Khatib S, Vaya JInhibition of serotonin re-uptake by licorice constituentsJ Mol Neurosci.(2003 Apr)
52.^Ha BG, Nagaoka M, Yonezawa T, Tanabe R, Woo JT, Kato H, Chung UI, Yagasaki KRegulatory mechanism for the stimulatory action of genistein on glucose uptake in vitro and in vivoJ Nutr Biochem.(2011 Jun 16. {Epub ahead of print}di)
53.^Hwang JT, Park IJ, Shin JI, Lee YK, Lee SK, Baik HW, Ha J, Park OJGenistein, EGCG, and capsaicin inhibit adipocyte differentiation process via activating AMP-activated protein kinaseBiochem Biophys Res Commun.(2005 Dec 16)
55.^Bazuine M, van den Broek PJ, Maassen JAGenistein directly inhibits GLUT4-mediated glucose uptake in 3T3-L1 adipocytesBiochem Biophys Res Commun.(2005 Jan 14)
56.^Akiyama T, Ishida J, Nakagawa S, Ogawara H, Watanabe S, Itoh N, Shibuya M, Fukami YGenistein, a specific inhibitor of tyrosine-specific protein kinasesJ Biol Chem.(1987 Apr 25)
60.^Dombrowicz D, Flamand V, Brigman KK, Koller BH, Kinet JPAbolition of anaphylaxis by targeted disruption of the high affinity immunoglobulin E receptor alpha chain geneCell.(1993 Dec 3)
63.^Yamashita S, Tsukamoto S, Kumazoe M, Kim YH, Yamada K, Tachibana HIsoflavones Suppress the Expression of the FcεRI High-Affinity Immunoglobulin E Receptor Independent of the Estrogen ReceptorJ Agric Food Chem.(2012 Aug 16)
64.^Sandford AJ, Shirakawa T, Moffatt MF, Daniels SE, Ra C, Faux JA, Young RP, Nakamura Y, Lathrop GM, Cookson WO, et alLocalisation of atopy and beta subunit of high-affinity IgE receptor (Fc epsilon RI) on chromosome 11qLancet.(1993 Feb 6)
65.^Sakai T, Kogiso M, Mitsuya K, Komatsu T, Yamamoto SGenistein suppresses development of spontaneous atopic-like dermatitis in NC/Nga miceJ Nutr Sci Vitaminol (Tokyo).(2006 Aug)
68.^Morito K, Hirose T, Kinjo J, Hirakawa T, Okawa M, Nohara T, Ogawa S, Inoue S, Muramatsu M, Masamune YInteraction of phytoestrogens with estrogen receptors alpha and betaBiol Pharm Bull.(2001 Apr)
69.^Hwang CS, Kwak HS, Lim HJ, Lee SH, Kang YS, Choe TB, Hur HG, Han KOIsoflavone metabolites and their in vitro dual functions: they can act as an estrogenic agonist or antagonist depending on the estrogen concentrationJ Steroid Biochem Mol Biol.(2006 Nov)
71.^Kuiper GG, Lemmen JG, Carlsson B, Corton JC, Safe SH, van der Saag PT, van der Burg B, Gustafsson JAInteraction of estrogenic chemicals and phytoestrogens with estrogen receptor betaEndocrinology.(1998 Oct)
72.^Harris HA, Bapat AR, Gonder DS, Frail DEThe ligand binding profiles of estrogen receptors alpha and beta are species dependentSteroids.(2002 Apr)
73.^Amer DA, Kretzschmar G, Müller N, Stanke N, Lindemann D, Vollmer GActivation of transgenic estrogen receptor-beta by selected phytoestrogens in a stably transduced rat serotonergic cell lineJ Steroid Biochem Mol Biol.(2010 Jun)
74.^Pihlajamaa P, Zhang FP, Saarinen L, Mikkonen L, Hautaniemi S, Jänne OAThe phytoestrogen genistein is a tissue-specific androgen receptor modulatorEndocrinology.(2011 Nov)
75.^Basak S, Pookot D, Noonan EJ, Dahiya RGenistein down-regulates androgen receptor by modulating HDAC6-Hsp90 chaperone functionMol Cancer Ther.(2008 Oct)
77.^Ohno S, Nakajima Y, Inoue K, Nakazawa H, Nakajin SGenistein administration decreases serum corticosterone and testosterone levels in ratsLife Sci.(2003 Dec 26)
82.^Bae M, Woo M, Kusuma IW, Arung ET, Yang CH, Kim YUInhibitory effects of isoflavonoids on rat prostate testosterone 5α-reductaseJ Acupunct Meridian Stud.(2012 Dec)
83.^Lehraiki A, Chamaillard C, Krust A, Habert R, Levacher CGenistein impairs early testosterone production in fetal mouse testis via estrogen receptor alphaToxicol In Vitro.(2011 Dec)
86.^Mizrachi D, Wang Z, Sharma KK, Gupta MK, Xu K, Dwyer CR, Auchus RJWhy human cytochrome P450c21 is a progesterone 21-hydroxylaseBiochemistry.(2011 May 17)
87.^Hasegawa E, Nakagawa S, Sato M, Tachikawa E, Yamato SEffect of polyphenols on production of steroid hormones from human adrenocortical NCI-H295R cellsBiol Pharm Bull.(2013)
88.^Chang EC, Charn TH, Park SH, Helferich WG, Komm B, Katzenellenbogen JA, Katzenellenbogen BSEstrogen Receptors alpha and beta as determinants of gene expression: influence of ligand, dose, and chromatin bindingMol Endocrinol.(2008 May)
90.^Wang TT, Sathyamoorthy N, Phang JMMolecular effects of genistein on estrogen receptor mediated pathwaysCarcinogenesis.(1996 Feb)
92.^Andres S, Abraham K, Appel KE, Lampen ARisks and benefits of dietary isoflavones for cancerCrit Rev Toxicol.(2011 Jul)
94.^Shimizu H, Ross RK, Bernstein L, Yatani R, Henderson BE, Mack TMCancers of the prostate and breast among Japanese and white immigrants in Los Angeles CountyBr J Cancer.(1991 Jun)
96.^Kousidou OC, Mitropoulou TN, Roussidis AE, Kletsas D, Theocharis AD, Karamanos NKGenistein suppresses the invasive potential of human breast cancer cells through transcriptional regulation of metalloproteinases and their tissue inhibitorsInt J Oncol.(2005 Apr)
99.^Jones RG, Plas DR, Kubek S, Buzzai M, Mu J, Xu Y, Birnbaum MJ, Thompson CBAMP-activated protein kinase induces a p53-dependent metabolic checkpointMol Cell.(2005 Apr 29)
100.^Meisse D, Van de Casteele M, Beauloye C, Hainault I, Kefas BA, Rider MH, Foufelle F, Hue LSustained activation of AMP-activated protein kinase induces c-Jun N-terminal kinase activation and apoptosis in liver cellsFEBS Lett.(2002 Aug 28)
102.^Osborne CKTamoxifen in the treatment of breast cancerN Engl J Med.(1998 Nov 26)
104.^Liu B, Edgerton S, Yang X, Kim A, Ordonez-Ercan D, Mason T, Alvarez K, McKimmey C, Liu N, Thor ALow-dose dietary phytoestrogen abrogates tamoxifen-associated mammary tumor preventionCancer Res.(2005 Feb 1)
105.^Constantinou AI, White BE, Tonetti D, Yang Y, Liang W, Li W, van Breemen RBThe soy isoflavone daidzein improves the capacity of tamoxifen to prevent mammary tumoursEur J Cancer.(2005 Mar)
108.^Mouridsen H, Gershanovich M, Sun Y, Pérez-Carrión R, Boni C, Monnier A, Apffelstaedt J, Smith R, Sleeboom HP, Jänicke F, Pluzanska A, Dank M, Becquart D, Bapsy PP, Salminen E, Snyder R, Lassus M, Verbeek JA, Staffler B, Chaudri-Ross HA, Dugan MSuperior efficacy of letrozole versus tamoxifen as first-line therapy for postmenopausal women with advanced breast cancer: results of a phase III study of the International Letrozole Breast Cancer GroupJ Clin Oncol.(2001 May 15)
109.^Foster BC, Vandenhoek S, Hana J, Krantis A, Akhtar MH, Bryan M, Budzinski JW, Ramputh A, Arnason JTIn vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural productsPhytomedicine.(2003 May)
110.^Almstrup K, Fernández MF, Petersen JH, Olea N, Skakkebaek NE, Leffers HDual effects of phytoestrogens result in u-shaped dose-response curvesEnviron Health Perspect.(2002 Aug)
111.^McMullen MH, Hamilton-Reeves JM, Bonorden MJ, Wangen KE, Phipps WR, Feirtag JM, Kurzer MSConsumption of Lactobacillus acidophilus and Bifidobacterium longum does not alter phytoestrogen metabolism and plasma hormones in men: a pilot studyJ Altern Complement Med.(2006 Nov)
112.^Bonorden MJ, Greany KA, Wangen KE, Phipps WR, Feirtag J, Adlercreutz H, Kurzer MSConsumption of Lactobacillus acidophilus and Bifidobacterium longum do not alter urinary equol excretion and plasma reproductive hormones in premenopausal womenEur J Clin Nutr.(2004 Dec)