Dr. Cassandra Simmons, chief of obstetrics and gynecology at NewYork-Presbyterian and Columbia, explains perimenopause and the hormonal shifts that can lead to symptoms like night sweats, brain fog, and fatigue. She breaks down how declining estrogen, progesterone, and testosterone affect the body and discusses a range of treatment options—from lifestyle strategies and supplements to hormone therapy. Dr. Simmons also offers reassurance that this often-overwhelming transition is manageable with the right support and care.