People with the condition being studied as well as healthy people can participate in a study. The FDA has very strict requirements that specify which studies involve healthy volunteers and which studies involve patients with the condition being studied.

The research team conducting the study will review each volunteer's medical history and the study requirements to determine who can participate. The team will also tell you what it means to be involved in the study and what the risks and benefits are during the informed consent process.

The informed consent process takes place before you join the study. A doctor, nurse, or another person on the team will explain why the study is being done, and what you can expect. You can ask any questions you have about the study during this time.