Research & Regulation
Phase 1 Clinical Trial
Also called: Phase I, phase one
Definition
An early stage of human clinical development that commonly emphasizes safety, tolerability, pharmacokinetics, and dose-ranging information.
What Phase 1 Clinical Trial means
Phase 1 studies are usually designed to answer early human questions rather than prove a broad clinical benefit. Study populations and designs vary by therapeutic area.
Why the distinction matters
Findings from Phase 1 can support later studies, but early signals should not be treated as equivalent to confirmatory evidence.
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Related glossary terms
Research & Regulation
Phase 2 Clinical Trial
A stage of human clinical development that commonly explores efficacy signals, dose selection, and continued safety assessment.
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Phase 3 Clinical Trial
A later-stage clinical trial designed to provide substantial evidence about efficacy and safety in the intended population and use context.
Pharmacology & Biology
Pharmacokinetics (PK)
The study of how a drug or compound moves through the body over time, including absorption, distribution, metabolism, and elimination.
Research & Regulation
Investigational
A compound, product, or use that is being studied and has not received approval for general marketing for that use.
Published September 6, 2026. BACToBasics glossary pages are educational definitions only and do not provide medical, dosing, preparation, treatment, or product-selection advice.