Phase 1 drug trials typically involve how many healthy volunteers?

• A. 10-20 healthy volunteers
• B. 20-100 healthy volunteers
• C. 100-500 healthy volunteers
• D. 500-1000 healthy volunteers

Answer: (B)

Phase I trials focus on safety, tolerability, and pharmacokinetics in humans, using a small number of healthy volunteers when appropriate. The goal is to determine safe starting doses and how the drug is processed in the body, not to assess efficacy. A typical healthy volunteer cohort is about 20–100 participants, which provides enough data on safety signals and PK variability without exposing too many people to potential risk. Smaller numbers may miss uncommon adverse effects or variability, while larger trials move into later-phase objectives and require more resources. So 20–100 aligns with common Phase I healthy volunteer practice.