What does the 3rd stage of drug testing involve?
If it passes all other tests, it's tested on human volunteers in a clinical trial. First, it's tested on healthy volunteers to make sure that it doesn't have any harmful effects when the body is working normally. At the start of the trial, a low dose is given which is gradually increased. The drugs are then tested on people suffering the illness if the results from testing healthy volunteers are good. The optimum dose is found - most effective and least side effects. To test whether it works, double-blind trials are done