EVERY PHASE, EXPLORED.
Interactive phase explorer
Phase I Studies
Learn how a new approach behaves in the body and what amount is well tolerated.
Beyond the four phases
Beyond the four phases
Observational Studies
Researchers watch and record health information over time without assigning a study product. Many involve questionnaires or routine visits.
Beyond the four phases
Healthy Volunteer Studies
Some studies, often early phase or observational, invite people without the condition being studied so researchers can compare results.
Featured tools
Interactive phase explorer
Tap through Phase I to Phase IV and compare goals, group sizes, and visit patterns.
Try it
Research explainers
Plain language explainers on screening, consent, and what study visits can look like.
Opportunity directory
Browse general study categories to understand which kinds of research exist.
Trial glossary
Short definitions for the research terms you will see in study listings.
Comparison guides
Side by side views of how phases differ in purpose and commitment.
FAQ center
Straight answers to common questions about volunteering in research.
Optional courtesy coordination
If you ask, we can organize your stated interests and, with your separate consent, pass them to one independent program.
How it works
Four simple moves.
Explore
Browse the phases and glossary at your own pace.
Choose
Pick optional text messages, only the ones you want.
Ask
Send a question or request courtesy coordination.
Decide
Independent study teams handle their own screening and consent.
Questions, answered.
Does Trial Phase Explorer enroll people in trials?
No. We are an independent trial phase resource. Independent study teams handle their own screening, consent, and enrollment.
Do I have to sign up for texts to use the site?
No. Every article, guide, and tool is available without signing up. Text lessons are completely optional.
Will my phone number be shared?
Mobile opt-in data and SMS consent are never sold, shared, rented, or transferred to third parties for marketing or lead generation.
What is courtesy coordination?
If you ask, we organize the interests you share and, only with your separate consent, pass your contact details to one independent program. It never guarantees acceptance.
Can I stop text messages?
Yes. Reply STOP, UNSUBSCRIBE, CANCEL, END, or QUIT at any time. Reply HELP for help.
Get trial phase texts. Stop anytime.
Trial Phase Explorer is an independent clinical trial phase resource. It is not a research organization, research sponsor, investigator site, or healthcare provider, and it does not enroll, screen, or qualify anyone for a trial. Content is for general information only and is not health advice.