1. What Are Clinical Trials?
A clinical trial is a research study conducted with human volunteers to evaluate a medical intervention — such as a drug, device, surgical procedure, behavioral change, or diagnostic test. Before any treatment reaches patients, it must pass through a carefully regulated series of trials that test its safety and effectiveness.
Clinical trials are conducted at hospitals, universities, community health centers, and sometimes virtually. Researchers design each trial with a specific scientific question: Does this new drug lower blood pressure better than existing options? Does early screening reduce cancer mortality? Can a mobile app help people manage chronic pain?
The benefits of participating extend in two directions. For the individual, a trial may offer early access to a promising new therapy, close medical monitoring, and often free treatment for the condition being studied. For society, trials generate the evidence that drives medical progress — every treatment your doctor prescribes today was first tested in a clinical trial.
Key fact: As of 2026, ClinicalTrials.gov lists over 450,000 registered studies in 221 countries. At any given time, tens of thousands are actively recruiting participants.
Who can participate?
Every trial has specific eligibility criteria — inclusion and exclusion factors that determine who can join. Common criteria include age range, medical diagnosis, disease stage or severity, prior treatment history, laboratory values, and general health status. These criteria exist both to protect participant safety and to ensure the trial answers its scientific question clearly.
If you don't qualify for one trial, you may qualify for another. Eligibility criteria differ significantly between studies, and new trials open every day.
2. Trial Phases Explained
Trials are organized into phases, each building on the results of the previous one. Understanding the phases helps you know what to expect and how to interpret a trial's risk-benefit profile.
In practice, Phase 3 trials often offer the best balance of evidence and potential benefit for patients — they compare new treatments directly against standard-of-care options in large, rigorously monitored settings. Phase 1 trials carry more uncertainty but provide access to very early-stage treatments, which can be meaningful for patients who have exhausted other options.
What about placebo-controlled trials?
Some trials use a placebo (an inactive treatment) as a comparison group. When an effective standard treatment exists, ethical guidelines require that the control group receive that standard treatment rather than a placebo. In fields where no standard treatment exists, placebo controls may be used. The trial's description on ClinicalTrials.gov will always disclose whether a placebo is involved and what the control group receives.
3. How to Search for Clinical Trials
Finding the right trial is a multi-step process. Here's a practical approach:
Step 1: Clarify what you're looking for
Before you search, gather key information: your diagnosis and stage, your current and past treatments, your age, and your location (and how far you're willing to travel). This makes it much faster to assess eligibility once you find relevant trials.
Step 2: Search TrialFinder
TrialFinder lets you search ClinicalTrials.gov in real time, filtered by condition, location, age, sex, and trial phase. Enter your condition to see a ranked, up-to-date list of recruiting studies. You can also browse condition-specific pages for popular diagnoses like breast cancer, type 2 diabetes, Alzheimer's disease, lung cancer, and heart disease.
Step 3: Review trial details on ClinicalTrials.gov
When a study looks interesting, click through to the full ClinicalTrials.gov listing. Read the eligibility criteria carefully, check the trial's status (Recruiting vs. Not Yet Recruiting), note the study locations, and review what the intervention involves.
Step 4: Contact the study team
Every listing on ClinicalTrials.gov includes a contact email or phone number for the study coordinator. You don't need a referral. Call or email directly, describe your situation briefly, and ask whether you might qualify. The coordinator will walk you through the pre-screening process — typically a short phone call reviewing your diagnosis, treatment history, and any key lab values.
Step 5: Discuss with your doctor
Your treating physician or specialist is an essential partner in this process. They can review the protocol, advise on whether the trial aligns with your overall care plan, and help coordinate your records. Some oncologists and specialists have direct relationships with research teams and can offer warm referrals.
Tip: Don't limit yourself to trials at local hospitals. Many major academic medical centers (Mayo Clinic, Johns Hopkins, Memorial Sloan Kettering, MD Anderson, etc.) run trials that accept patients from across the country — and some trials are even conducted by mail or telehealth visit.
4. Questions to Ask Before Enrolling
Before signing informed consent, take time to ask the study team these key questions. A good research team will welcome every one of them.
About the trial itself
- What is the purpose of this trial, and what question are you trying to answer?
- What phase is this trial, and how many participants are enrolled?
- What are my chances of receiving the experimental treatment versus the control treatment?
- Has this treatment been tested in Phase 1 or 2? What were the results?
- What are the known or potential side effects? How are they managed?
About participation logistics
- How often will I need to come in for visits, and how long will each visit take?
- Are any visits done via telehealth or at home?
- What tests and procedures are required, and which are covered by the trial?
- Will I need to travel, and does the trial provide travel reimbursement?
- How long will I be enrolled, and what happens at the end of the trial?
About your rights and options
- Can I continue seeing my regular doctor while enrolled?
- What happens if I want to withdraw? Will my standard care be affected?
- If the experimental treatment works, will I be able to continue receiving it after the trial ends?
- Who can I contact if I have concerns or questions during the trial?
5. Common Myths — Debunked
Misconceptions about clinical trials prevent many eligible patients from considering them. Here are the most common myths and the facts that correct them.
"Clinical trials are a last resort for people who have run out of options."
Trials are increasingly recommended at all stages of treatment, including as a first-line option. Some patients enroll in prevention trials before they are ever diagnosed. Discussing trials with your doctor early — not just when other treatments have failed — gives you the most options.
"I might get a sugar pill and receive no treatment at all."
Ethical guidelines require that control groups in trials receive the current best available standard of care. Pure placebo groups are only used when no proven treatment exists for the condition being studied. This is clearly disclosed in the trial's informed consent document before you agree to participate.
"Participating in a trial means giving up control of my healthcare."
Your participation is entirely voluntary. You can withdraw from a trial at any time, for any reason, without penalty or loss of access to standard care. You also continue to make all decisions about your health in consultation with your regular care team.
"Clinical trials are only for young, healthy people."
Most trials actively seek participants who actually have the condition being studied — including older adults, patients with comorbidities, and those who have already undergone prior treatments. Diversity in trial populations is a priority in modern research because it produces results that are applicable to the real-world patient population.
"I'll have to pay a lot to participate."
The experimental treatment and all protocol-required tests are almost always provided at no cost to participants. Some trials even pay stipends to compensate for time and travel. Your regular medical costs (unrelated to the trial) may still apply, so it's worth asking the study coordinator for a clear breakdown of what is and isn't covered.
More Resources
Browse our condition-specific pages to find trials relevant to your diagnosis: