First-in-Human (FIH) refers to the first administration of an investigational product to human participants, typically in early-phase clinical studies.
FIH trials focus on safety, tolerability, pharmacokinetics, and dose escalation under closely controlled conditions. Because uncertainty and potential risk are highest at this stage, oversight emphasizes conservative dosing rationale, stopping rules, and intensive monitoring. Ethics review focuses heavily on risk mitigation, informed consent clarity, and participant safety safeguards. FIH studies establish foundational human safety evidence that informs subsequent dose selection and development strategy.