Research is the way doctors and scientists learn about new ways to prevent and treat conditions, and find answers to many questions about health, disease or human behavior. As a participant in a research study, you play a critical role in improving health care and future treatments; however, it is also an important personal decision.
Some participants may have a disease or condition the researchers are studying, while other participants are healthy volunteers. In each research study, there are requirements regarding who can participate. This is called inclusion criteria. There also are reasons why someone might not qualify, known as exclusion criteria.
Being part of a research study is completely voluntary, and you can change your mind at any time.
Every study has a research team who work together to follow what's called a "protocol" — a detailed plan for the study. The protocol balances the potential benefits and risks to participants, and answer specific research questions.
Research team members include:
Other individuals also may help with a research study, such as pharmacists, lab technicians, dieticians who help with participants dietary needs, social workers and office staff.
Clinical trials are medical research studies in which people participate as research volunteers. There are some clinical trials that help researchers understand how a disease or disorder progresses through a person’s life.
Clinical trials are a means of developing treatments, medications, or new approaches for dealing with diseases and conditions.
In a clinical trial, researchers observe the effects an intervention may have on participants. The researcher collects data (information) about how the intervention affects participants’ health. The intervention may be a medical drug or device or procedure; it might also be a behavior change that participants agree to try.
There are several types of clinical research studies, including:
The goal of clinical trials is to determine if these treatment, prevention, and behavior approaches are safe and effective. People take part in clinical trials for many reasons. Healthy volunteers say they take part to help others and to contribute to moving science forward. People with an illness or disease also take part to help others, but also to possibly receive the newest treatment and to have added (or extra) care and attention from the clinical trial staff. Clinical trials offer hope for many people and a chance to help researchers find better treatments for others in the future.

Clinical trials are done in different phases. In Phase I trials, researchers test an intervention in a small group of healthy volunteers to discover if the intervention is safe, the correct dosage, and if volunteers have any reactions to or side effects from the intervention. In Phase II-Phase IV studies, researchers want to learn more about the safety of the intervention and how well it works in larger groups of participants.
Phase I trials
Researchers test a drug or treatment in a small group of people (20–80) for the first time. The purpose is to study the drug or treatment to learn about safety and identify side effects.
The new drug or treatment is given to a larger group of people (100–300) to determine its effectiveness and to further study its safety.
The new drug or treatment is given to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it with standard or similar treatments, and collect information that will allow the new drug or treatment to be used safely.
After a drug is approved by the FDA and made available to the public, researchers track its safety in the general population, seeking more information about a drug or treatment’s benefits, and optimal use.
For most clinical trials a participant is assigned to either an intervention or a control group. Intervention group participants receive the intervention that is being tested.Control group participants do not receive the intervention. Instead they might receive the standard treatment for the disease or condition, or they might receive a placebo, which looks or feels like the intervention, but it is not an active medicine or treatment. The control group helps the researchers understand the effects of the experimental intervention.
Your group assignment often happens by chance. If you take part in a clinical trial, you might not get the experimental treatment that is being tested. In some cases, you won’t know the group to which you are assigned.
There are benefits and risks for research participants. Being part of a clinical trial allows the participants to have access to experimental treatments that are not yet available to the public, while also helping others by contributing to the development of a new medical treatment or procedure. Additional benefits include:
Risks for research participants include:
The specific risks associated with a research protocol are described in detail in the informed consent document, which participants are asked to consider and sign before participating in research. Also, a member of the research team will explain the study and answer any questions about the study. Before deciding to participate, it's important to carefully consider risks and possible benefits.
One good way to find out if there are any clinical trials that might help you is to ask your doctor. Other sources of information include:
FDA works to protect participants in clinical trials and to ensure that people have reliable information before deciding whether to join a clinical trial. The Federal government has regulations and guidelines for clinical research to protect participants from unreasonable risks. Although efforts are made to control the risks to participants, some may be unavoidable because we are still learning more about the medical treatments in the study.
The government requires researchers to give prospective participants complete and accurate information about what will happen during the trial. Before joining a particular study, you will be given an informed consent document that describes your rights as a participant, as well as details about the study, including potential risks. Signing it indicates that you understand that the trial is research and that you may leave at any time. The informed consent is part of the process that makes sure you understand the known risks associated with the study.
You and your doctor are a team in your care. This material is for informational purposes only and it is not intended to be a substitute for medical advice. Talk to your doctor to decide the right course of treatment for you.