What is Biest? Biest is a treatment used in bio-identical hormone replacement therapy (BHRT) for menopausal symptoms and anti-aging treatment.  Biest is the combination of estradiol (E2) and estriol (E3). Estradiol is a fairly strong form of estrogen and estriol is a very gentle form of estrogen. Because Estriol is a gentle form of estrogen, […]