Saira Hameed's book *Signals* explores how hormones govern every aspect of human life, blending personal narrative with medical insight. As an endocrinologist, Hameed treats patients whose bodies seem destabilized by invisible internal forces, often helping them reclaim hope and even motherhood. Early in her career, she learned that medicine is less about highbrow science and more about listening to patients' stories. Her approach mirrors the classic doctor-as-detective model, where small clues—like a tan or a forgotten prescription—unlock deeper truths. Hameed's writing is empathetic and self-aware, avoiding any trace of superiority. She acknowledges the rising tide of AI in medicine but argues that endocrinology will always require human connection and interpretation. One of the most moving parts of the book covers her experience treating COVID-19 patients, capturing the horror and helplessness of the pandemic. Through vivid character portraits—a terrified mother, a jovial journalist, a young woman shaped by childhood neglect—Hameed illustrates both the power and limits of medical intervention. She reflects on the need to balance hope with realism, warning against over-reliance on redemptive endings. *Signals* serves as both an inspiring guide for aspiring doctors and a humbling reminder for everyone of how little we control. As Hameed notes, hormones govern our moods, weight, and energy more than behavior or willpower.

The book, published by Faber at £20 for 336 pages, follows her bestselling debut *The Full Diet* and is reviewed by Sarah Neville, the FT's global health editor.