The essentials
What clinical trials are
Clinical trials are research studies involving people. They evaluate health-related approaches such as medicines, devices, procedures, behavioral programs, or ways to prevent and understand illness.
Why they matter
Trials help researchers learn whether an approach is safe and effective and how it compares with existing options. Volunteers make this learning possible.
Phases of clinical research
Phases describe different research goals; not every study follows the same sequence.
Early phase and Phase 1
Safety, dose, and how an intervention behaves.
Phase 2
Continued safety assessment and early signs of effect.
Phase 3
Larger comparisons of benefits and risks.
Phase 4
Broader use after an intervention is approved.
Eligibility and informed consent
Every trial has criteria describing who may take part. A research team reviews these criteria; finding a listing does not mean someone is eligible.
Informed consent
The team should explain purpose, procedures, alternatives, risks, benefits, privacy, costs, and the right to leave.
Risks and benefits
Possible risks and benefits differ by study, and benefits are not guaranteed.
Healthy volunteers
Some studies welcome people without the condition to understand typical health or compare findings.
Questions volunteers may ask
- What is the study trying to learn?
- What visits, tests, or procedures are involved?
- What risks, discomforts, and possible benefits should I understand?
- What costs or travel expenses are covered?
- How will my information be protected?
- Who can I contact with questions or concerns?
How to read a trial listing
Start with recruitment status, study purpose, eligibility, intervention, locations, sponsor, contacts, dates, and outcomes. Registry entries can be technical and may change.
Visit ClinicalTrials.gov (external website)