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Wednesday, November 5, 2008

Warning: 7,8-Benzoflavone Is Carcinogenic

There is a compound used by bodybuilders that acts as a powerful aromatase inhibitor, reducing estrogen and allowing users to be less estrogen dominant. The substance, however, has been demonstrated to be carcinogenic. The substance is 7,8-Benzoflavone. The following line of reasoning demonstrates that 7,8-Benzoflavone may be carcinogenic in humans.

  1. Benzo[a]pyrene is "highly carcinogenic." Benzo[a]pyrene is found in cigarette smoke, car exhaust fumes, "marijuana smoke, incense smoke, wood smoke, and in charbroiled food." It is even in burnt toast.1
  2. "A vast number of studies over the previous three decades have documented links between benzo[a]pyrene and cancers."1
  3. 7,8-Benzoflavone has been demonstrated in rat studies to "stimulate . . . benzo(a)pyrene tumorigenesis." In some cases 7,8-Benzoflavone reduces cancer, but in others (such as when it is applied topically with benzo(a)pyrene) it increases cancer.2
Although 7,8-Benzoflavone is an aromatase inhibitor, preventing the conversion of testosterone into estrogen, and in some cases preventing cancer,3-5 the fact that 7,8-Benzoflavone has a double nature and is, in other cases, carcinogenic6-9 (such as when it is combined with benzo[a]pyrene), should make us think twice before using it in humans.

  2. Proc. Nat. Acad. Sci. Vol. 69, No. 4, pp. 824-828, April 1972. Aryl Hydrocarbon Hydroxylase- and Polycyclic Hydrocarbon Tumorigenesis: Effect of the Enzyme Inhibitor 7,8-Benzoflavone on Tumorigenesis and Macromolecule Binding. (benzo(a)pyrene/7,12-dimethylbenz(a)anthracene/DNA, RNA, and protein binding/mouse skin). Nadao Kinoshita and Harry V. Gelboin. Available online at: (Accessed Nov. 5, 2008.)
  3. Progress in Medicinal Chemistry. By G. P. Ellis, Geoffrey Buckle West. P. 59. Published by Elsevier, 1988.,8-Benzoflavone+aromatase+inhibiter&source=web&ots=5X-a4VHRlF&sig=08nlIPUT-Zp5UP7Yu-6v-uLzmxk&hl=en&sa=X&oi=book_result&resnum=2&ct=result (Accessed Nov. 5, 2008.)
  4. Action of 7,8-benzoflavone on incidence of skin tumors induced by polycyclic hydrocarbons. Bulletin of Experimental Biology and Medicine. NY: Springer. Issue Volume 87, Number 5 / May, 1979. DOI 10.1007/BF00806687. Pp. 474-475. December 13, 2004. Online at: (Accessed Nov. 6, 2008.)
  5. Effects of ellipticine, flavone, and 7,8-benzoflavone upon 7,12-dimethylbenz[a]anthracene, 7,14-dimethyldibenzo[a,h]anthracene and dibenzo[a,h]anthracene initiated skin tumors in mice. Alworth WL, Slaga TJ. Carcinogenesis. 1985 Apr.6(4):487-493. (Accessed Nov. 6, 2008.)
  6. Role of Metabolic Activation in the Carcinogenicity of Estrogens: Studies in an Animal Liver Tumor Model. Manfred Metzler, G√ľnter Blaich, and Angelika M. Tritscher. Environmental Health Perspectives. August. Vol. 88, pp. 117-121, 1990. (Accessed Nov. 6, 2008.)
  7. The author of a review states that "7,8-benzoflavone actually appears to enhance tumor formation by benzo(a)pyrene . . . indicating the complex interaction of effects of benzoflavones upon various cutaneous polycyclic aromatic hydrocarbon metabolizing enzymes." [Emphasis supplied.] Dermal Absorption and Toxicity Assessment. By Michael S. Roberts, Kenneth A. Walters. Informa Health Care, 1998, p. 76. Online at:,8-benzoflavone+humans&source=web&ots=-fiDMv8wED&sig=LlMOM4qvgk1UoclQ81wt1QnKZzE (Accessed Nov. 7, 2008.)
  8. 7,8-Benzoflavone stimulates the metabolic activation of aflatoxin B1 to mutagens by human liver. Biochem Biophys Res Commun. 1978 May 15;82(1):348-55. Buening MK, Fortner JG, Kappas A, Corney AH. Available online at: (Accessed Nov. 7, 2008.)
  9. Yet another study comes to a rather frightening conclusion for those who have been using 7,8-Benzoflavone, indicating that “the addition of . . . 7, 8-benzoflavone to human liver microsomes caused a many-fold stimulation in the hydroxylation of benzo(a)pyrene, the metabolism of aflatoxin B1 to 2,3-dihydro-2,3-dihydroxyaflatoxin B1, and the metabolic activation of aflatoxin B1 to mutagenic products.” [Emphasis supplied.] “Activation and Inhibition of Benzo(a)pyrene and Aflatoxin B1 Metabolism in Human Liver Microsomes by Naturally Occurring Flavonoids.” Mildred K. Buening, Richard L. Chang, Mou-Tuan Huang, Joseph G. Fortner, Alexander W. Wood, and Allan H. Conney. Cancer Research 41, 67-72, January 1981. Available online at (Accessed Nov. 7, 2008.)


stkm said...

GOOD INFORMATION.As a physician i would like to complement on ur efforts.

Anonymous said...

You are not a physician, if you were you would know that this person knows jack shit all about this. They can't spell and seem to miss the point that 7,8 benzo is very different from benzopyrenes.

Anonymous said...

This is really a bad interpretation of data.

Anonymous said...

These papers say nothing about benzoflavone being toxic, just that they potentially worsen the effect of the poison aflatoxin. Aflatoxin isn't part of the standard diet in any form, in fact we have laws in the US to prevent aflatoxins from being in the food supply. So, the headline "benzoflavone is carcinogenic" is 100% misleading and false. None of the papers cited seem to show benzoflavones as being carcogens at all.