Informed consent in clinical trials: What GCP requires and why it matters
Before a single participant can join a clinical trial, one non-negotiable step must take place: informed consent. It is not a formality, not a signature on a form, and certainly not a box to tick before the study can begin. Informed consent in clinical trials is the ethical and legal foundation upon which every clinical study rests. To understand why these standards exist, read our guide on why good clinical practice is important. With the introduction of ICH E6 R3, the requirements have become more rigorous, more participant-centred, and more relevant than ever.
Informed consent in clinical trials is the process by which a potential participant voluntarily agrees to take part in a study after being fully informed of its purpose, risks, benefits, and alternatives. Under ICH GCP E6 R3, it is a continuous process, not a one-time signature, and must be documented at every stage
What is informed consent?
What does informed consent mean?
Define it in plain language. Informed consent means a person receives all the information they need to make a free, voluntary, and fully understanding decision about whether to participate in a clinical trial. The word “informed” is doing the heavy lifting here, it is not enough to obtain a signature. The participant must genuinely understand what they are agreeing to.
What is informed consent in healthcare vs. in clinical trials?
In routine healthcare, consent is typically obtained once before a procedure. In clinical trials, informed consent is a rich, ongoing process that continues throughout the entire study. The participant’s circumstances, the available data, and the trial protocol can all change, and when they do, the consent process must reflect those changes.
Which of the following best describes a component of informed consent?
The core components of informed consent in clinical trials are: a description of the study and its purpose; the foreseeable risks and discomforts; the expected benefits; the available alternatives; a statement about confidentiality; information about compensation if injury occurs; contact details for questions; and a clear statement that participation is voluntary and can be withdrawn at any time without penalty.
Why is informed consent important in clinical research?
Why is consent important? the ethical argument
The Nuremberg Code (1947), the Declaration of Helsinki (1964), and the Belmont Report (1979) — all born from real cases of participants being exploited. Informed consent exists because history showed us what happens when it doesn’t. The Tuskegee Syphilis Study and the Thalidomide tragedy are two examples where the absence of proper informed consent caused catastrophic, irreversible harm.
Why is informed consent important? the regulatory argument
Without valid informed consent in clinical trials, a regulatory body such as the FDA or EMA can invalidate an entire study. No consent, no approval. It is that straightforward. A flawed consent process is one of the most common findings in FDA Warning Letters and EMA inspection reports.
Why is informed consent important? the participant trust argument
Clinical research depends on public trust. If participants do not trust the consent process, they will not enrol. Low enrolment is one of the leading causes of clinical trial failure. Proper informed consent in clinical trials is not just a legal requirement, it is the mechanism through which clinical research maintains its social licence to operate.
GCP requirements for informed consent - what ICH E6 R3 demands
The informed consent process under ICH GCP
Consent must be obtained before any study-related procedure begins; it must be documented in writing; the participant must be given adequate time to consider; a witness may be required in certain circumstances; and the original signed form must be retained as an essential document.
Informed consent is Principle 2 of the ICH GCP framework. For a full breakdown of all 11 principles, see our complete guide to ICH GCP principles.
ICH E6 R3 changes to informed consent
ICH E6 R3 introduces several important updates to the informed consent process:
- Consent is now explicitly described as a continuous process, not a single event
- The consent materials must be concise, clear, and understandable — not written at a regulatory or legal complexity level
- R3 acknowledges a wider range of consent methods, including remote and electronic approaches
- There is a stronger emphasis on participant comprehension, if a person does not understand, the consent is not valid regardless of whether they signed
- R3 also addresses consent in the context of decentralised clinical trials, where participants may never visit a site in person.
For a full side-by-side comparison of what changed between R2 and R3 across all areas of GCP, see our detailed R2 vs R3 guide.
Who must obtain informed consent?
Under GCP, the Principal Investigator (PI) holds overall responsibility for the informed consent process at a site. However, the PI may delegate the task of conducting consent discussions to a qualified sub-investigator or Clinical Research Coordinator (CRC), provided this delegation is documented on the delegation of authority log. The person obtaining consent must be trained, knowledgeable about the trial, and capable of answering participant questions. The sponsor or CRA may never obtain informed consent, this responsibility stays at the site level.
Electronic informed consent (eConsent) in clinical trials
What is eConsent?
eConsent is the use of electronic systems and multimedia tools, such as videos, interactive modules, and digital signature platforms, to support or replace the traditional paper-based consent process. It is not simply scanning a paper form. True eConsent delivers information in a structured, auditable, and participant-friendly format.
What ICH E6 R3 says about eConsent
R3 is the first version of the ICH GCP guidelines to explicitly embrace eConsent as a legitimate and encouraged method. The guideline makes clear that technology should serve the participant, not the sponsor’s operational convenience. Key requirements: the system must be validated; participants must have the ability to ask questions (synchronously or asynchronously); an audit trail must exist; and the participant must always have the option to receive a paper copy.
Benefits and limitations of eConsent in clinical trials
Benefits: improved comprehension through multimedia; accessible on any device; audit trail built in; easier to manage re-consent when protocol amendments occur; suitable for decentralised trials. Limitations: digital literacy gaps in some populations; potential for participants to click through without reading; requires validated systems and IT infrastructure; regulatory acceptance varies by country.
Common mistakes in informed consent documentation
1. Obtaining consent after study procedures have already begun
One of the most serious GCP violations. Any study-related procedure, including screening tests, conducted before a signed consent form is obtained is a protocol deviation at minimum, and a serious GCP violation in most cases.
2. Using an outdated version of the consent form
When a protocol is amended, a new consent form is typically required. Using a superseded version is a common audit finding. Sites must have a version control system and must re-consent participants using the current approved version.
3. Insufficient documentation of the consent discussion
A signature proves a form was signed, it does not prove the participant understood. Notes in the source documents recording that the consent discussion took place, that questions were answered, and that the participant had adequate time, are equally important.
4. Failure to re-consent after a protocol amendment
When significant new information emerges, a new risk, a protocol change, new safety data, participants must be re-consented. Failing to do this is a frequent inspection finding.
Re-consent failures are among the most common findings during regulatory inspections. Our GCP audit preparation guide covers how to protect your site before an inspector arrives.
5. Witness and translator requirements not met
When a participant is illiterate or when a language barrier exists, specific GCP requirements apply. A witness must be present and must sign the form. The use of an unqualified interpreter is a documentation error that can invalidate consent entirely.
6. No documentation of the participant's right to withdraw
The consent form and the consent discussion must explicitly confirm that the participant can withdraw at any time without consequences. If this is absent from either the form or the source documentation, it is a finding.
Can doctors record patients without consent? A note on privacy in clinical trials
While this question typically arises in general healthcare, it has direct relevance to clinical trials. Under GCP and data protection regulations such as GDPR in Europe and HIPAA in the United States, any recording, data collection, or documentation involving a participant requires explicit consent. In the context of clinical trials, this extends to audio or video recordings of consent discussions, remote monitoring visits, and telemedicine interactions in decentralised trials. The principle is consistent: no data, of any kind, may be collected from a participant without their prior knowledge and consent.
How to document informed consent correctly under GCP
Essential documents relating to informed consent
The signed and dated consent form (participant and person obtaining consent); the IRB/IEC approved version of the consent form with its version number and date; the delegation of authority log showing who is authorised to obtain consent; source documentation recording the consent discussion; and any re-consent documentation following amendments.
The ALCOA++ standard applied to consent documentation
The ALCOA++ principles that govern all clinical trial documentation apply equally, and critically, to informed consent records.. Attributable, who obtained consent and when. Legible, the signature and date must be readable. Contemporaneous — documented at the time of the discussion. Original, no photocopied signatures. Accurate, the version used must be the IRB/IEC-approved version.
Informed consent in clinical trials: key takeaways
Informed consent in clinical trials is one of the most scrutinised areas of GCP compliance, and for excellent reason. It is the moment where science meets humanity. When done well, informed consent protects participants, strengthens data integrity, and builds the public trust that clinical research relies on. When it is done poorly, it puts participants at risk, exposes sites to regulatory action, and can unravel years of scientific work.
Before closing this guide, here are the principles every clinical research professional should carry into their daily practice:
Informed consent is a process, not a document. The signed form is evidence that a conversation happened; it is not a substitute for that conversation. The quality of the discussion matters as much as the paperwork.
Comprehension is the standard, not the signature. Under ICH E6 R3, consent is only valid if the participant genuinely understands what they agreed to. A signature from someone who did not understand the trial is not valid informed consent in clinical trials, legally or ethically.
Timing is non-negotiable. No study-related procedure — including screening assessments — may begin before informed consent has been obtained and documented. There are no exceptions.
Re-consent is an ongoing responsibility. Informed consent in clinical trials does not end at enrolment. When new information emerges or the protocol changes, re-consent is required before the participant continues. Tracking this is a shared responsibility between the PI, the CRC, and the sponsor.
Documentation must meet ALCOA++ standards. Every element of the consent process — who obtained it, when, which version was used, what questions were asked, and how re-consent was handled — must be traceable, legible, and contemporaneous.
eConsent is now a legitimate and encouraged option. ICH E6 R3 explicitly supports electronic informed consent in clinical trials, provided the system is validated, the audit trail is intact, and participant comprehension is actively supported — not just assumed.
Delegation is permitted, but responsibility is not transferable. The PI may delegate the consent discussion to a trained CRC or sub-investigator, but the PI retains overall accountability for the quality and validity of the informed consent process at the site.
Conclusion
Informed consent in clinical trials sits at the intersection of ethics, regulation, and human dignity. From the early lessons of the Nuremberg Code to the modernised, participant-centred framework of ICH E6 R3, the principle has remained constant: every person who joins a clinical trial deserves to understand exactly what they are entering into, and to make that choice freely.
For clinical research professionals, mastering the informed consent process is not simply about passing an audit or avoiding a Warning Letter. It is about recognising that behind every CRF, every data point, and every protocol deviation report, there is a person who trusted you enough to participate in research. That trust begins and must be continuously earned through informed consent.
As the industry moves deeper into the R3 era, with decentralised trials, eConsent platforms, and increasingly complex study designs, the fundamentals do not change. The tools evolve, the documentation systems evolve, and the regulatory expectations evolve, but the ethical obligation to a fully informed, freely consenting participant remains exactly where it has always been: at the very centre of everything we do in clinical research.
Are you confident your informed consent process meets ICH E6 R3 standards?
Understanding what GCP requires is the first step, applying it correctly in a real trial is where certification makes the difference.
If you are new to GCP and want to understand the full certification pathway first, start with our 2026 GCP certification guide. At PharmaEduCenter, our ICH GCP E6 R3 training covers the full informed consent process, documentation requirements, eConsent, and the practical skills you need to conduct compliant, participant-centred clinical trials.
Our courses are accredited by the Faculty of Pharmaceutical Medicine of the Royal College of Physicians (UK) and approved by TransCelerate, making your certificate recognised by sponsors and regulators worldwide.
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FAQ: Informed consent in clinical trials
What is the purpose of informed consent in clinical trials?
The purpose of informed consent in clinical trials is to ensure that participants voluntarily agree to take part after receiving complete, understandable information about the study. It protects participant rights, fulfils GCP and regulatory requirements, and underpins the ethical validity of the entire research process.
Who is responsible for obtaining informed consent in a clinical trial?
The Principal Investigator (PI) holds overall responsibility. The PI may delegate the consent discussion to a qualified sub-investigator or Clinical Research Coordinator (CRC), but this delegation must be documented. Sponsors and CRAs may not obtain informed consent.
How long must informed consent documents be retained?
Under ICH GCP, informed consent documents must be retained for at least 15 years after the completion of the trial, or longer if required by local regulations or the sponsor’s requirements.
What happens if informed consent is not obtained correctly?
A failure in the informed consent process is a serious GCP violation. It can result in a regulatory authority invalidating trial data, issuing a Warning Letter, placing a clinical hold on the study, or rejecting a marketing authorisation application. At the site level, it can result in disqualification of the investigator.
What is re-consent and when is it required?
Re-consent is the process of obtaining a new signed consent form from an existing participant when significant new information becomes available — such as new safety findings, a protocol amendment that changes the risk profile, or a change to the study procedures. It must be completed before the participant continues in the trial.
What is the difference between informed consent in clinical trials and general medical consent?
In routine healthcare, consent is typically a one-time event before a procedure. In clinical trials, informed consent is a continuous process that persists throughout the entire study, requires specific documentation standards, and is subject to independent ethics committee oversight and regulatory inspection.
Is eConsent accepted by all regulatory authorities?
eConsent is increasingly accepted globally, but requirements vary by country and region. ICH E6 R3 supports its use. The FDA and EMA have issued specific guidance on electronic consent. Sponsors should confirm acceptability with local regulatory authorities before implementing eConsent in any jurisdiction.
Can a participant withdraw consent after joining a clinical trial?
Yes. A fundamental GCP principle is that participation is entirely voluntary. Any participant may withdraw consent at any time and for any reason, without penalty or loss of benefits to which they are otherwise entitled. This right must be clearly stated in the consent form and in the consent discussion.
