Estrogen dominance refers to an imbalance where estrogen outweighs progesterone—whether due to excess estrogen, low progesterone, or both. This condition can affect both women and men, but is most common in women of reproductive or perimenopausal age. Symptoms often include heavy, painful periods, breast tenderness, mood changes, and stubborn weight gain. Functional medicine investigates the root causes of estrogen dominance, such as liver congestion, gut dysbiosis, chronic stress, and exposure to xenoestrogens (from plastics and personal care products). With the right testing and support, estrogen metabolism can be improved and symptoms reduced naturally.