Originated 1970s by Dr. Henry Lemon, who tested estrogen levels in 24 hour urine samples and found that an EQ > 1 strongly correlated with a higher survival rate after breast cancer.24 Further research conducted by Lemon, Heidel, et al., a meta - analysis of published fractional estrogen excretion collected from 2,846 healthy women worldwide
aged 15 to 59 years, with a risk of breast cancer varying five-fold, found that an EQ < 1 reflects increased rates of oxidation of estrone or estradiol to 4 - OH catechols (also referred to in the literature as the 3,4 - catechol estrogen quinones), which have been identified as the principal proximal
human mammary carcinogens after menarche, while an EQ > 1 reflects
conversion to protective 2 - OH estrogen metabolites.2526