Estriol (E3)
The weakest of the three estrogens, and the one that dominates in pregnancy. Outside pregnancy it is a minor player, measured to complete the estrogen picture in a full female work-up.
What the numbers mean
These are the ranges BioForge works to. They are not the same as a lab's reference range, which is built from the general population rather than from people who feel well.
What moves Estriol (E3)
Rises by orders of magnitude in pregnancy — where it is measured in ng/mL, not pg/mL — and with compounded estriol creams. Outside those two situations it stays near the floor, and a low result is normal rather than a deficiency to correct.
Related markers in Testosterone, Estrogen & Binding
This page is educational and is not medical advice. Ranges are general and do not account for your history, medications or symptoms — a single number never decides a protocol. Your results are interpreted by a licensed clinician alongside everything else about you. Back to the Learning Center
Want to know where your numbers actually sit?
Every BioForge protocol starts from your own bloodwork. The first 15-to-30-minute call is free.