The recent approval by the United States Food and Drug Administration of a clinical trial involving a product derived from human embryonic stem cells, along with recent concerns about unproven stem cell therapies being offered to patients, highlight the importance of regulation at the critical stage of beginning human trials of novel therapies. The regulations governing therapeutic products (drugs and related products) are one part of the broader legal framework, but will play an increasingly prominent role as we move into clinical translation. The classification of products as drugs or biologics, on one hand, or minimally manipulated cell and tissue products for homologous use, on the other, will determine the requirements that will apply, including whether use in clinical trials requires approval. Product regulation works alongside other parts of the legal and policy framework, notably research ethics review and legal responsibilities of medical professionals, that play important though limited roles. Three key developments and challenges currently facing product regulation and related areas will affect stem cell research in this phase: regulatory reform, fragmentation, and capacity.