In regulatory risk assessment, how is QSAR used?

• A. QSAR predicts toxicity of chemicals based on structure; used to prioritize testing, fill data gaps, and support screening decisions.
• B. QSAR is used to measure actual toxic effects in humans in clinical trials.
• C. Regulatory agencies discard QSAR data due to unreliability.
• D. QSAR replaces all animal testing with direct predictions.

Answer: (A)

QSAR uses chemical structure to predict potential toxicity through computational models. In regulatory risk assessment, this approach helps quickly screen large numbers of chemicals, prioritize those most likely to pose hazards for further testing, and fill data gaps where experimental data are unavailable. The predictions support screening decisions and help shape weight-of-evidence assessments, making the overall assessment more efficient while guiding where confirmatory tests are needed. It doesn’t measure actual human effects in clinical trials, and it does not replace all animal testing with direct predictions. Instead, QSAR is a tool to reduce and refine testing, providing early hazard indications that must be confirmed by experimental data when needed.