Hormonal treatments are used by millions of women, first for contraception and later to manage menopausal symptoms. These treatments include newer formulations, doses, and routes of administration, yet much of the existing safety evidence is based on older hormones studied decades ago. REVEAL is a large Nordic research programme designed to establish how modern hormonal products can be used safely across a woman’s life. Using high-quality health data from approximately 14 million women in Denmark, Sweden, Norway, and Finland, REVEAL will identify when hormone therapy can be started, which products are safest, which groups may face higher risks, and how long treatment can continue safely. The project will generate clear, product-specific evidence on major health outcomes, including heart disease, mental health, dementia, and cancer, supporting better clinical decision-making, clearer product information, and safer, more personalised care for women.