Clinical Trial Guide
Everything you need to know before joining a clinical trial
A plain language guide to how clinical trials work, what participation looks like, and what you are entitled to know.
What is a clinical trial?
A clinical trial is a research study that tests whether a treatment, medication, device, or approach is safe and effective for people. Trials are run by research teams at hospitals, universities, clinics, and sometimes in patients’ own homes.
Every clinical trial in the United States and Canada follows strict rules set by government regulators. Before a trial can begin, an independent ethics board must review and approve it. In the US this is called an Institutional Review Board. In Canada it is called a Research Ethics Board. Their job is to protect participants.
Participating is always voluntary. You can never be pressured to join, and you can leave at any point without it affecting your regular medical care.
How the process works, step by step
- 1You find a trial that looks relevant.Search a public registry such as ClinicalTrials.gov, or use Trial Finder, to find a study that matches your condition.
- 2You review the eligibility criteria.Every trial has inclusion and exclusion criteria that determine who can participate.
- 3You contact the trial team.If you think you may qualify, you reach out to the study site listed on the trial page. This is usually a nurse coordinator.
- 4You attend a screening visit.If the initial call goes well, you are invited for a screening visit to confirm whether you meet all criteria.
- 5You review informed consent.If you qualify, the team walks you through the informed consent document. You have the right to take it home.
Types of trials you might find
In person trials
You visit a clinic, hospital, or research center for study visits. These are the most common type. Visit frequency varies widely.
Remote trials
Some or all of your participation happens from home. You may use a phone app, a wearable device, or video appointments.
Observational studies
These do not test a treatment. Researchers observe participants over time to understand a condition or track symptoms.
Natural history studies
Common in rare diseases. Researchers follow patients over time to understand how a condition progresses without an experimental drug.
The four phases, explained simply
Safety and dosage. A small group of about 20 to 80 people.
Efficacy and safety. Typically several hundred people.
Confirmation. Thousands of participants across multiple sites.
Long term monitoring after regulatory approval.
Compensation and what trials cover
- The study treatment itself is almost always provided at no cost to participants.
- Many trials cover or reimburse travel expenses, including gas and parking.
- Some trials pay a stipend for your time and inconvenience.
- Trials do not typically cover your regular medical care.
- Always ask the study coordinator before you commit.
Receiving compensation does not mean a trial is less rigorous or less safe. Compensation is standard practice in clinical research.
Informed consent and your rights
Before you join any trial, you will receive an informed consent document. It explains what the study is testing, what you will be asked to do, the known risks, the potential benefits, whether there is a placebo, whether the study is blinded, your right to leave at any time, and who to contact for questions.
Signing is not a contract. You can withdraw at any time for any reason and it will not affect your access to standard medical care. You have the right to know exactly what you are participating in, to ask questions, and to leave at any stage.
Why some recruiting trials never respond
A study can stay listed as recruiting long after it has paused or filled. Listings also go stale when a site loses staff or funding. That is why contacting trials from a raw registry search can be frustrating. Our Trial Finder tool filters for studies that are still active and responsive, so you can focus your energy where it counts.
Search official public registries
The most reliable place to search is a government registry, updated directly by research teams.
- ClinicalTrials.gov
The comprehensive database of clinical studies worldwide, managed by the U.S. National Library of Medicine.
- Health Canada
Official directory for clinical trials involving drugs authorized for use in Canada.
- NIH Research
Educational resources and study listings for research participants from the National Institutes of Health.
- GARD (rare diseases)
NIH resource for the rare disease community to help identify relevant trials and understand listings.
- WHO ICTRP
The World Health Organization platform linking clinical trial registries around the globe.
- FDA Resources
Information from the U.S. Food and Drug Administration on clinical studies for trial participants.