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Understanding informed consent in clinical trials
Learn what informed consent means, what should be explained before you join a study, and which questions to ask before signing.
Informed consent means the research team gives you the information you need before you decide whether to join — and the conversation continues throughout the study. It is a rights process, not just paperwork. It has three parts.
Informed consent, in plain terms
1 · Information
You're told what's involved
The study team explains the trial — purpose, what happens, risks, benefits, alternatives, privacy, and costs. A fair question to ask: "What exactly will happen if I join?"
2 · Understanding
You understand enough to decide
You should understand enough to decide. It's fair to ask for simpler language or more time. A fair question: "Can you explain this in simpler language?"
3 · Choice
You decide freely
You decide freely, without pressure — and you can say no, or leave later. A fair question: "What happens if I say no?"
Before joining, you should understand
- What the study is trying to learn
- What will happen to you
- How long participation may last
- Which procedures are research
- What risks or side effects may happen
- What benefits are realistic
- What other options you have
- How your information is protected
- What costs you may have
- Who to call with problems — and that participation is voluntary
What HHS and NIH say
HHS describes informed consent as three core features: disclosing the needed information, helping the person understand it, and supporting a voluntary decision. NIH adds that taking part is voluntary and you can leave at any time.
What informed consent is not
Not just a signature
It documents a conversation
A signed consent form documents the conversation — it doesn't replace it. HHS says a signed form alone does not make the process adequate.
Not a contract
You aren't locked in
Participation is voluntary, and you're free to withdraw at any time.
Not proof the trial is right for you
Agreeing isn't a recommendation
It means the study was explained and you agreed to take part. It does not mean the treatment will work, that risks are gone, or that the trial is better than standard care.
Not the same as eligibility
Screening still happens
You can sign consent and still need screening tests before the team confirms whether you can take part.
What you should understand before you sign
HHS lists the basic elements a consent form should cover. Use this as a self-check — for each item, ask yourself whether you could explain it in your own words. If not, that's a good thing to ask the study team about. This is a conversation-prep tool, not medical or legal advice.
- Why the study is being done
- What will happen to me
- How long it lasts
- Which parts are research
- What risks are possible
- What benefits are realistic
- What other options I have
- How my information is protected
- What costs may apply
- Who I call with problems, and that I can leave
Confusing phrases in a consent form
| Consent-form phrase | Plain-language meaning | A question to ask |
|---|---|---|
| "Investigational" | The treatment, test, or approach is still being studied. | What is already known about it? |
| "Foreseeable risks" | Risks the study team knows may happen. | Which risks are common? Which are serious? |
| "Alternative procedures or treatments" | Other options besides joining the study. | What would you recommend if I don't join? |
| "Confidentiality" | How your personal and health information will be protected. | Who can access my records? |
| "Research-related injury" | Harm that may happen because of the study. | Who pays for care if I'm injured? |
| "Voluntary participation" | You choose whether to join. | Will my regular care change if I say no? |
| "Withdrawal" | Leaving the study after joining. | What happens if I stop? |
| "Legally authorized representative" | Someone allowed to decide for a person who cannot consent. | Who can decide if I cannot? |
| "Protocol" | The study plan. | What parts of the protocol affect me? |
| "IRB" | A review board that helps protect participants. | Was this study reviewed by an IRB? |
Questions to ask before signing
You don't have to use all of these — pick the ones that matter to you and bring them to the conversation.
Study purpose
- Can you explain the purpose of this study in plain language?
- Why do researchers think this approach may help?
- Which parts of this study are experimental?
- Has this been studied before?
What happens to you
- What will happen at each visit?
- How many visits are required, and how long do they take?
- Will I need extra blood tests, scans, biopsies, or procedures?
- Can any visits happen remotely?
Risks & benefits
- What side effects are most common?
- What side effects are serious?
- What is still unknown?
- Could I personally benefit, or is the main goal to help future patients?
Alternatives
- What are my standard care options?
- What happens if I don't join?
- Can I start standard treatment and consider a trial later?
- Would joining the trial delay any care?
Costs
- What does the study pay for?
- What might my insurance be billed for?
- Are travel, lodging, parking, meals, or childcare covered?
- If I'm injured because of the study, who pays for care?
Your rights
- Can I leave the trial later?
- Will leaving affect my regular medical care?
- Who do I call with concerns about my rights?
- Can I take this form home to discuss with family or my doctor?
Your "before I sign" short list
If you bring nothing else, bring these: What is the purpose of this study? What will happen to me? What are the risks? What are the possible benefits? What are my other options? What costs could I have? Who do I call with problems? Can I leave the study later?
Before, during, and after signing
- 1
Before signing
Learn & decide
Read the consent form, ask questions and request plain language, talk with your clinician, family, or caregiver, ask about alternatives, costs, risks, and the visit schedule — then decide whether you want to continue.
- 2
After signing, before starting
Screening
Screening tests may still be needed. The team may review labs, scans, diagnosis, and treatment history, and you may still be told you don't qualify.
- 3
During the study
Ongoing
You can keep asking questions, new risk or benefit information should be shared with you, the team monitors your health and study safety — and you can leave the study at any time.
If you're unsure — slow down
Pause and ask for help if you feel rushed, don't understand the study purpose or the risks, the possible benefits sound guaranteed, you're unsure whether there are other options, you don't know who to call with side effects, you're confused about costs, or you feel your regular care depends on saying yes. It's reasonable to ask for more time, plain-language explanations, to bring a caregiver, or to ask whether a translator is available.
Things you can say
- "Can you explain this in simpler language?"
- "Can we go through the risks and costs one more time?"
- "Can I take this home and discuss it with someone I trust?"
- "Is there a translator or interpreter available?"
Key takeaways
- Informed consent is a process, not just a signature.
- The team should explain purpose, procedures, risks, benefits, alternatives, privacy, costs, and contacts.
- Participation is voluntary.
- You can ask questions, take time, and leave a study later.
- ClinicalMatchMate helps you prepare for the conversation — it doesn't make the decision for you.
Sources
Last reviewed 2026-06-03 · James Mbualungu, MD/MBA candidate · Content v1.0
Questions for your first conversation · Glossary of trial terms · Back to guides