Everything you need to know about clinical trials

Clinical trials are the best way to understand how the medicines and the medical practices we produce affect our health. When it comes down to it, clinical trials can be summarized in just a few simple steps.


Research sites work out the basic theory and pitch their ideas to clinical trial sponsors by means of a research plan. The idea undergoes some preliminary testing. Normally, the hypothesis is tested through observation of microorganisms and laboratory animals. Once deemed safe, the medication/practice needs to be checked and given the green light by government bodies in order to proceed with patient recruitment for human trials.


From then on, once the study is underway, it is just a case of adding more and more people. This is the primary factor in determining phase 1 clinical trials from those of a later stage.


Once, phase 3 clinical trials are successful, the US Food and Drug Association (FDA) can now decide if the treatment will be approved for market.

Phase I clinical trials

Phase I clinical trials test whether drugs are safe to use in humans. These trials are typically small — they enroll approximately 20 to 100 volunteers. Some phase I clinical trials only look for healthy volunteers, who may be compensated for participating.

Phase II clinical trials

Phase II clinical trials test both the safety and effectiveness of a drug or medical device. Trials in this stage can last from several months to a few years, and recruit up to several hundred patients with the condition to take part.

Phase III clinical trials

Phase III clinical trials are usually the largest — these trials test a potential treatment in hundreds to thousands of people in a randomized, blind study. This testing phase can last several years as the FDA gathers thorough data about the drug’s effectiveness and potential side effects.

Phase IV clinical trials

Also known as “Post-Approval Research and Monitoring”, Phase IV takes place after a drug or device has been approved. In this phase, pharmaceutical companies monitor a drug’s long-term impact. This phase is crucial, because it may take a few years for longer-term side effects to appear.