Biochanin A is a natural isoflavone with diverse biological actions, most notably as a phytoestrogen. It can affect hormone levels by inhibiting 5α-reductase and 17β-hydroxysteroid dehydrogenase or altering aromatase (CYP19A1) activity.^1,2 Also known as 4’-methyl genistein, biochanin A can be metabolized in vivo to genistein , another phytoestrogen with diverse effects.³ Biochanin A also intersects with signaling through peroxisome proliferator-activated receptors (PPARs), as it activates PPARγ (EC50 = 19 µM) and has also been shown to activate a PPARα promoter.⁴ Moreover, it increases the expression of the PPARγ coactivator PGC-1α, promoting mitochondrial biogenesis.⁵ Biochanin A also inhibits fatty acid amide hydrolase (IC50 = 2.4 µM) and acts as an agonist of the aryl hydrocarbon receptor (EC50 = 0.25 µM).^6,7