The explanation involves politics, economics, and the powerful pharmaceutical industry in the United States. Pharmaceutical companies cannot patent bioidentical compounds; they can however, patent synthetic hormones. They are highly profitable. A patent guarantees them an exclusive right to manufacture and profit from their product, therefore little research and marketing goes into natural hormones. Much of what physicians know about drugs comes directly from pharmaceutical companies promoting a product. Because pharmaceutical companies don’t manufacture bioidentical hormones, most physicians do not learn about them unless they do personal research.