Estrone
Estrone (E1) is one of the three major endogenous human estrogens, alongside estradiol (E2) and estriol (E3). It is a weaker estrogen than estradiol, with substantially lower receptor binding affinity at the estrogen receptor, estimated at roughly 4 to 8 percent of E2's affinity at ERα.
Estrone is the predominant circulating estrogen after menopause. Peripheral aromatization of androstenedione in adipose tissue and muscle produces it, rather than ovarian follicles. In premenopausal women, the ovaries and peripheral tissues produce estrone in smaller amounts alongside estradiol.
Elevated estrone in reproductive-aged women, particularly in obesity and PCOS, produces a relatively high estrone-to-estradiol ratio. This shift may alter estrogen receptor signaling and endometrial responsiveness. In RRM hormonal profiling, estradiol is the primary measured estrogen, with estrone assessed when androgen excess or metabolic dysfunction is part of the clinical picture.
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.