What is a clinical trial?

A clinical trial is a research study where volunteers agree to test a new medicine. The trial is designed to discover whether this new medicine works and if it is safe. It’s only through clinical trials and the help of volunteers like you that important questions about new medicines can be answered.

What are clinical trials for?

Clinical trials test potential new medicines to see:

  • If the medicine works
  • If there are safety concerns
  • What the side effects are

Are clinical trials safe?

Strict rules about how to run a clinical trial were put in place to protect the rights, safety, privacy, and well-being of trial volunteers.

How are clinical trials set up?

Every clinical trial has a plan, also known as a protocol. The plan outlines the details of the trial, including which people may enrol, how long the trial will take, and how the results will be measured. Before the trial can start, an independent ethics committee and the local government’s health authorities must approve this plan.

Keep in mind, clinical trials will only take place if:

  • There is a scientific and medical reason for the trial
  • There are more benefits than risks for the trial volunteers

The 4 phases of clinical research

Before a medicine can be tested in a clinical trial, it must first be tested in animals to confirm that it is safe. Testing new medicines usually goes through the following 4 phases.



Basic safety

These trials test a new medicine to see if it is safe. In this phase, a small number of people, who may be healthy, are given the medicine. When trial doctors are sure it is safe, the medicine can move to Phase II.



Does the medication work?

These trials test the new medicine on a larger group of people (usually a few hundred) with a specific disease for a longer time. This is done to see if or how the medicine works. This is also known as a medicine’s efficacy.



Testing in a larger group

These trials test medicines in even larger groups of people (typically several hundred) with a specific disease. This phase compares the new medicine to the usual medicine used for the disease, or to a placebo (dummy medicine that doesn’t have active ingredients).

Doctors will often use the “blinded” method for Phase II and Phase III trials. This means that neither the participant nor the doctor will know which medicine or placebo the volunteer receives.



Post-approval testing

In these trials, the medicine tested has already been approved for use. Phase IV trials include the largest group of participants (usually several hundred to thousands of volunteers). Phase IV trials are sometimes called Post Marketing Surveillance Trials.

Did you know?


It’s important to attend every clinical visit so the trial team can better understand the results.


You will be monitored closely and your team will be available for questions and support.


You can join a trial at any phase.


Clinical trials are one of the most important steps to finding new medicines.

Get more answers from our FAQs
Interested in participating?