Alpha-napthoflavone, the sly fat-maker in testosterone boosters
Not so long ago we expressed our worries about alpha-naphthoflavone, a component in some bodybuilding supplements. Its safety had not really been studied, and the way it works suggested that side effects were likely. What's more the substance does not occur in nature, [Planta Med. 2010 May;76(7):662-4.] so we weren't that surprised by the article in Nutrients: according to nutritionists at Taipei Medical University, alpha-naphthoflavone stimulates the growth and development of fat cells.
Alpha-naphthflavone inhibits the production of aromatase, the enzyme that converts testosterone into estradiol. [Science. 1984 Sep 7;225(4666):1032-4.] That's why it's found in some bodybuilding supplements, especially those intended to boost testosterone levels. It looks as though alpha-naphthoflavone works via the aryl-hydrocarbon receptor [Mol Pharmacol. 1993 Feb;43(2):200-6.] and affects more processes than just the production of aromatase, we prophesied in March 2015. [ergogenics.org 08.03.2015]
Researchers at Taipei Medical University write in Nutrients that alpha-naphthoflavone induces the growth of fat cells in test tubes. The more alpha-naphthoflavone the researchers added to adult fat cells, the more fat the cells started to accumulate.
Alpha-naphthoflavone activated the production of a number of substances in the fat cells, including VEGF, a hormone that stimulates the creation of blood cells. Fat cells are better able to grow if they are provided with nutrients and growth factors by blood vessels.
Alpha-naphthoflavone reduced the secretion of IGF-1, and boosted the synthesis of the inflammatory factor interleukin-6. Interleukin-6 can promote the growth of fat cells.
The figure below shows the effect in vitro of increasing concentrations of alpha-naphthoflavone on fat cells and blood vessel cells. Alpha-naphthoflavone not only induces the fat cells to grow, but also induces both fat cells and blood vessel cells to form structures.
CM = medium.
"Alpha-naphthoflavone increased triglyceride accumulation in mature adipocytes and enhanced mature adipocyte-stimulated tube formation in endothelial cells", the researchers wrote.
Nutrients. 2015 Apr 30;7(5):3166-83.