Understanding Informed Consent in Clinical Trials

What informed consent actually means

Informed consent is an ongoing process of communication between you and the research team. It begins before you join a trial and continues until the trial ends. The process has two components:

• Information: The research team provides you with a detailed explanation of the study, including its purpose, procedures, risks, potential benefits, alternatives, and your rights as a participant.
• Voluntary agreement: After receiving and understanding this information, you freely choose whether to participate. No one can pressure, coerce, or rush you into a decision.

The written consent document is an important part of this process, but it is not the whole of it. The document serves as a reference, while the real informed consent happens in the conversations you have with the research team — asking questions, discussing concerns, and making sure you genuinely understand what you are agreeing to.

What the consent document should include

Federal regulations require that informed consent documents cover specific topics. When you review the form, look for clear explanations of each of the following:

• Purpose of the research: What question is the trial trying to answer?
• Procedures: What exactly will happen to you during the trial? How often will you visit the clinic? What tests or treatments will you receive?
• Duration: How long will the trial last, and how much of your time will it require?
• Risks and discomforts: What are the known side effects and potential risks? How likely are they?
• Benefits: What potential benefits might you experience? The document should be honest — in early-phase trials, you may not benefit directly, and the document should say so.
• Alternatives: What other treatments are available to you if you choose not to join the trial?
• Confidentiality: How will your personal and medical information be protected?
• Costs: What costs, if any, will you be responsible for? What does the trial sponsor cover?
• Compensation for injury: What happens if you are harmed as a result of the trial? What medical care will be provided, and who pays for it?
• Contacts: Who should you call with questions, concerns, or emergencies?
• Voluntary participation: A clear statement that participation is voluntary and that you can withdraw at any time without penalty.

If any of these topics are missing, unclear, or written in language you cannot understand, ask the research team to explain. You should never sign a document you do not fully comprehend.

Your rights during informed consent

The informed consent process is designed to protect you. You have the right to:

• Ask questions. There is no such thing as a stupid question. The research team's job is to make sure you understand, regardless of how many times you need something explained.
• Take your time. You are not obligated to decide on the spot. You can take the consent document home, read it carefully, and discuss it with family, friends, or your personal doctor.
• Have a companion present. You can bring a family member, friend, or advocate to the informed consent discussion. A second pair of ears can help you process the information.
• Ask for a simpler explanation. Consent documents can be lengthy and technical. If the language is confusing, ask the team to walk you through it in everyday words.
• Say no. You can decline to participate at any point during the consent process, and you do not owe anyone an explanation.
• Request a copy. You should receive a signed copy of the consent document for your records.

Questions to ask before signing

Beyond the topics covered in the consent document, consider asking the following before you make your decision:

• Can you explain the biggest risk in a way I can tell my family?
• What has happened to other people who have taken this treatment so far?
• If something goes wrong, what medical care will be provided, and will I be charged for it?
• Will I be told which group I am in — treatment or control?
• What happens at the end of the trial? Will I still have access to the treatment if it works?
• How will you let me know if new risks are discovered during the trial?
• Who can I contact if I have a concern about how the trial is being conducted?

For a comprehensive list, see our guide on questions to ask your doctor about clinical trials.

You can take the form home

This is worth emphasizing because many people feel pressured to sign during the first visit. You are always allowed to take the consent document home. Read it in a quiet environment. Highlight sections you do not understand. Discuss it with your family, your primary care doctor, or anyone whose judgment you trust.

A reputable research team will never rush you. If you feel pressured to sign immediately, that is a red flag. Legitimate trials want participants who are genuinely informed, not participants who felt cornered.

Consent is ongoing — you can withdraw at any time

Signing the consent form is the beginning, not the end. Throughout the trial, the research team is required to keep you informed of any new developments that might affect your willingness to participate. This could include newly discovered side effects, changes to the study protocol, or early results that alter the risk-benefit picture.

If new information comes to light, the team may ask you to review and sign an updated consent form. You have every right to reconsider your participation at this point. And you can withdraw from the trial at any time, for any reason, even if nothing has changed — simply because you have changed your mind. Withdrawing will not affect your access to regular medical care.

Special consent situations

Standard informed consent assumes that the participant can read, understand, and voluntarily agree to the information provided. But not all situations are standard:

Children and adolescents

When the participant is a minor, a parent or legal guardian provides consent on their behalf. Children old enough to understand (generally age 7 and older) are also asked for their "assent" — their agreement to participate, explained in age-appropriate language. Learn more in our guide to pediatric trials.

Cognitive impairment

For participants with conditions that affect cognitive function, such as Alzheimer's disease or severe mental illness, a legally authorized representative may provide consent. The participant's wishes, to the extent they can express them, must still be considered. Additional safeguards are typically required by the IRB.

Emergency research

In rare cases, clinical trials study treatments for emergencies like cardiac arrest or severe trauma, where the patient cannot consent and there is no time to locate a family member. These studies require special FDA approval and extensive community notification. An independent monitor must confirm that traditional consent is impossible before a patient can be enrolled.

Non-English speakers

If you are more comfortable in a language other than English, you have the right to receive the consent document in your preferred language and to have a qualified interpreter present during discussions with the research team.

Next steps

Informed consent exists to put you in control. No legitimate researcher wants you to join a trial you do not understand. Take the time you need, ask every question that crosses your mind, and remember that "no" is always an acceptable answer.

If you are ready to explore trials, our guide on how to join a clinical trial walks you through the full enrollment process. You can also search for trials by condition here on TrialFinder, where eligibility criteria are translated into plain English.