How to Find a Clinical Trial

Medically Reviewed by Jennifer Robinson, MD on September 20, 2023
Written by Katherine Kam
3 min read

Are you trying to find a clinical trial to enter?

Each year, researchers recruit many volunteers into such trials to evaluate new medical treatments, drugs, or devices. Ultimately, clinical trials seek better ways to treat different diseases and conditions. Not only might the trial participants benefit, but so could patients in the future.

But you (or your doctor) have to know how to find those trials.

A good starting place is www.clinicaltrials.gov. This website, sponsored by the National Institutes of Health, offers information on more than 125,000 clinical trials in 180 countries. Some of those are recruiting patients; other trials are completed or terminated.

To start your search:

  • Go to www.clinicaltrials.gov.
  • Click on the link, "Search for Clinical Trials," on the home page.
  • Enter your search terms -- for example, a disease or intervention and a location: "heart attack" AND "aspirin" AND "California." Separate your multiple search terms with a capitalized "AND."

If you want to see all studies listed for your condition, see "Study Topics" on the right side of the home page. You'll find four links that allow you to list all studies by condition, drug intervention, location, or sponsor.

Studies that are recruiting will name a sponsor (for example, "University of Michigan" or "National Heart, Lung, and Blood Institute"). Further down the page, you'll also find a contact person, whom you can reach by phone or email to ask about participating.

If you find a clinical trial that interests you, feel free to ask many questions so that you understand as much as possible. Here are 13 useful questions, noted by ClinicalTrials.gov, to discuss with members of the health care team involved with the clinical trial:

  1. What is the purpose of the study?
  2. Who is going to be in the study?
  3. Why do researchers believe the experimental treatment being tested may be effective? Has it been tested before? If so, in what phase is the trial (see below)?
  4. What kinds of tests and experimental treatments are involved?
  5. How do the possible risks, side effects, and benefits in the study compare with my current treatment?
  6. How might this trial affect my daily life?
  7. How long will the trial last?
  8. Will hospitalization be required?
  9. Who will pay for the experimental treatment?
  10. Will I be reimbursed for other expenses?
  11. What type of long-term follow-up care is part of this study?
  12. How will I know if I get the placebo or the experimental treatment? Will results of the trials be provided to me?
  13. Who will be in charge of my care?

Clinical trials are carried out in phases, each with a different purpose. Here’s a description of the different questions that scientists try to answer during each phase:

  • Phase I:An experimental treatment is given to a small group of people (usually 20 to 80). The goal is to understand the best way to deliver the new treatment, check its safety, find a safe dosage range, and identify side effects.
  • Phase II: The drug or treatment being studied is given to a larger group of people (100-300) to test its effectiveness and to further evaluate safety. At this stage, there may or may not be a control group. People in a control group receive standard care but not the experimental therapy; people in treatment groups get the experimental therapy. A control group allows the researchers to compare the new therapy to other treatment, a placebo, or no treatment.
  • Phase III:The researchers give the experimental drug or treatment to large groups of people (1,000-3,000) to confirm effectiveness, monitor side effects, make comparisons to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely. During this phase, there's usually a control group and a treatment group. People are randomly assigned to one of those groups; you can't choose which group you'll be in, and if there is a placebo group, you likely won't know if you're getting the placebo or the experimental therapy.
  • Phase IV:This research phase takes place after the study drug or treatment has received FDA approval. These post-marketing studies gather additional information, including the drug's risks, benefits, and optimal use in a larger population.