The potential benefits of joining a clinical trial include access to an investigational treatment, regular clinical monitoring and the opportunity to contribute to medical research. The risks can include unknown side effects, receiving a placebo or comparator, the treatment not working and the time and commitment required to participate.
The important word is potential.
A clinical trial is designed to find out whether a treatment is safe and effective. If researchers already knew exactly how well it worked, there would be no need for the trial.
What are the benefits and risks of joining a clinical trial?
Here's the simplest way to look at the trade-offs:
| Benefit | The catch attached to it |
|---|---|
| Access to an investigational treatment | It may not work, and depending on the trial, you may receive a placebo or comparator instead |
| Regular monitoring, testing and clinical review | This can mean more appointments, blood tests and potential procedures |
| Study treatment and research-specific procedures may be provided at no cost | Your usual healthcare costs continue as normal |
| Travel or other expenses may be reimbursed | Reimbursement varies and may not cover costs such as time away from work |
| Contributing to research that helps future patients | There may be no direct medical benefit to you |
| A structured schedule with a dedicated study team | Study visits need to follow the protocol and may require a significant time commitment |
What are the potential benefits of a clinical trial?
Access to an investigational treatment. A clinical trial may give you access to a treatment that isn't otherwise available. This can be particularly relevant when existing treatment options are limited or haven't worked for you. However, access doesn't mean the treatment will work, and some trials may involve a placebo or comparator.
Regular monitoring and clinical review. Clinical trials often involve regular appointments, assessments and testing. This means changes in your health may be closely monitored throughout the study. The trade-off is that this level of monitoring can require considerably more time and appointments than your usual care.
Information about your own health. Screening and study assessments can sometimes provide additional information about your health. However, not every test is designed to diagnose conditions outside the purpose of the study, so a clinical trial shouldn't be treated as a substitute for your usual healthcare.
Contribution to medical research. Every registered medicine you've ever taken exists because people volunteered for trials, most of whom received no personal benefit from doing so.
What are the risks of joining a clinical trial?
Unknown side effects. Investigational treatments can have side effects, including effects researchers don't yet know about. Generally, earlier-phase trials involve greater uncertainty because less human safety information may be available.
You may receive a placebo or comparator. Some clinical trials randomly assign participants to different treatment groups. Depending on the trial, you could receive the investigational treatment, an existing treatment or a placebo.
The treatment may not work. There is no guarantee that an investigational treatment will improve your condition. Even if early research is promising, the purpose of a clinical trial is to determine whether the treatment actually works and whether its benefits outweigh its risks.
Time and commitment. The practical burden of a clinical trial can be significant. Appointments, travel, parking, time off work, diaries, fasting bloods, questionnaires or other study requirements can add up over weeks or months. Look at the full study schedule before agreeing to participate.
Additional procedures. Depending on the trial, you may have additional blood tests, imaging, ECGs, biopsies or other procedures. The research team should explain what each procedure involves and its potential risks before you consent.
Your other treatment options. Participating in a trial may affect which other treatments you can receive during the study. If you have other treatment options available, discuss them with your treating doctor or specialist before deciding.
Misconceptions in clinical trials worth clearing up
"Trials are a last resort." Not true. Trials investigate treatments at different stages of development and may recruit people at different stages of a condition. Some studies may require participants who are newly diagnosed, while others may look for people who have already tried certain treatments. Eligibility depends on the individual trial.
"You're a guinea pig." The phrase implies no oversight. In practice you're the most closely watched patient in the building: an ethics committee has vetted the protocol, a regulator has been notified, a named doctor is accountable for your safety, and every symptom you report is documented and assessed. You can also leave whenever you want, which no guinea pig can.
"It's free treatment." A clinical trial shouldn't be viewed as a way to access free medical treatment. The investigational treatment and research-specific procedures are generally provided without cost to participants, but other healthcare costs may continue.
How do I know if a clinical trial is right for me?
Here's our position, and it's a narrower answer than most sites will give you.
A trial is a good fit if you have a condition with limited or unsatisfactory approved options, your specialist agrees the trial is reasonable for you, you can realistically get to the site for every scheduled visit, and you can hold two ideas at once: that the treatment might help, and that it might do nothing.
A trial is a poor fit if you're enrolling mainly for the reimbursement, if the visit schedule only works in a version of your life where nothing goes wrong, if you're hoping to avoid a conversation with your specialist about standard treatment, or if you'd feel misled by being randomised to placebo. All four are reasons to say no, and saying no is a perfectly good outcome.
How should I decide whether to join a clinical trial?
- Get the consent form in advance and read it at home
- Write down the visit schedule on your actual calendar, including travel time. Look at it honestly
- Ask your treating specialist what they'd do, and what the alternatives are
- Ask the site the placebo question, the post-trial access question, and the withdrawal question
- Give yourself a night on it
If a site resists any part of that process, you've learned something useful.
The thing worth deciding before you sign, not after: what would make you withdraw. Write it down. Participants who've thought about their own limits in advance tend to stay in trials longer and report side effects more honestly, because leaving stops feeling like failure.
View our currently recruiting clinical trials →
Related reading: Are clinical trials safe? · What happens at each stage · Your rights as a participant