Exemestane is a powerful aromatase inhibitor (AI) that works by permanently deactivating the aromatase enzyme, which is responsible for converting testosterone into estrogen. Unlike reversible AIs, exemestane (also known as a “suicidal inhibitor”) binds irreversibly, making it a go-to choice for controlling estrogen long-term without rebound. Often used during or after anabolic cycles, it helps reduce water retention, prevent gynecomastia, and support a lean, hardened physique—all while protecting natural testosterone output.