Cimino C.O., Shelnutt S.R., Ronis M.J., Badger T.M. (1999) An LC-MS method to determine concentrations of isoflavones and their sulfate and glucuronide conjugates in urine. Clin Chim Acta 287:69-82 PubMed (10509897)

Compound Mean content
Genistein 1.36 mg/g
Daidzein 0.65 mg/g