Definition
Informed Consent
Informed consent is the process by which a prospective participant learns the purpose, procedures, risks, benefits and alternatives of a study and voluntarily agrees to take part, usually documented with a signed consent form.
2 min readReviewed September 14, 2026
Also known as: Informed consent form, ICF, Consent process, eConsent
Key facts
- FDA regulation
- 21 CFR Part 50, Subpart B
- HHS regulation
- 45 CFR 46.116 and 46.117 (the Common Rule)
- Registry statement
- 21 CFR 50.25(c): trial description available on ClinicalTrials.gov
- Emergency research exception
- 21 CFR 50.24
What is informed consent?
Informed consent is a process, not just a signature. Before enrollment, investigators must explain the study in language the participant can understand, allow time to consider it, answer questions and avoid coercion or undue influence. Consent continues through the trial as new information arises that may affect willingness to take part.
For FDA-regulated research, the requirements are in 21 CFR Part 50. For federally funded research, they are in the Common Rule at 45 CFR Part 46. The Institutional Review Board (IRB) approves the consent form and process before they are used.
What a consent form must include
Required elements include:
- A statement that the study involves research, with its purpose, expected duration and procedures, and which procedures are experimental.
- Reasonably foreseeable risks or discomforts, and any benefits that may reasonably be expected.
- Appropriate alternative procedures or treatments, if any.
- How the confidentiality of records will be maintained.
- For research involving more than minimal risk, whether compensation or medical treatment is available if injury occurs.
- Whom to contact with questions, and a statement that participation is voluntary and can stop at any time without penalty.
Exceptions and recent changes
The revised Common Rule, in effect since 2019, requires consent forms to begin with a concise and focused presentation of key information. FDA regulations allow an exception from informed consent for certain emergency research, and the 21st Century Cures Act of 2016 gave FDA authority to permit waivers or alterations of consent for minimal risk clinical investigations.
Children generally give assent while a parent or guardian gives permission. Electronic consent (eConsent) is permitted when it meets the same regulatory requirements as paper consent.
Why informed consent matters
Consent quality affects enrollment, retention and compliance. Long, dense forms can slow recruitment and contribute to dropouts, and consent problems are among the deficiencies FDA cites in clinical investigator inspections.
For decentralized trials, remote consent workflows and identity verification are core operational questions, and for sponsors, consent language determines how participant data and samples can be reused in later research.