Are Clinical Trials Safe?

Before a trial starts, it goes through strict reviews by ethics committees and regulatory agencies (like the FDA) to make sure the study is scientifically sound and participants receive all protections possible. Researchers are required to monitor safety throughout the study. No matter what, participants can leave at any time.

That said, because trials often involve experimental treatments, there can be unknown side effects, or the treatment might not work. Phase 1 trials carry the most risk, since they're the first time a drug is tested in humans. Later phases tend to be safer, since more is already known.