What is the significance of testing drugs on healthy volunteers in Stage 3?

Testing drugs on healthy volunteers in Stage 3 of drug development is crucial for revealing any harmful side effects. In this phase, the primary focus is to determine the safety profile of the drug, especially identifying any adverse reactions that might not have been evident in earlier trials involving animal testing or isolated cell studies. Healthy volunteers can provide important insights into how the drug affects the body, ensuring that potential risks are identified before the drug is administered to patients who are already ill and, therefore, potentially more vulnerable to side effects.

While assessing the drug's effectiveness, determining its usage, and considering stock availability are important aspects of drug development, they are not the primary objectives during this specific stage of testing on healthy volunteers. The focus here is on safety, which is critical to protect future patients who will use the drug in a clinical setting.