Are clinical trials safe?

Safety is the first priority in clinical research, and multiple layers of protection exist for people who take part. No trial can promise zero risk, but modern trials are designed, reviewed and monitored specifically to keep risks as low as possible and to detect problems early.

Before a study can begin, it must be approved by an independent ethics committee. These committees include scientists, health professionals and community members, and their role is to make sure the study design is sound, the risks are justified and participants' rights are protected.

Most new treatments are studied extensively in the laboratory before they are ever given to people, and early phase trials start with small doses in small groups. Regulators such as national medicines agencies also review trial plans for new medicines before they proceed.

During a trial, your health is monitored closely by the research team, often more closely than in routine care. Larger studies also have independent safety monitoring boards that regularly review the data while the trial is running. If concerning patterns appear, a trial can be paused or stopped.

Every trial has some risks, which can include side effects, the possibility that the new approach works less well than existing care, and the time commitment involved. The research team must explain the known risks and potential benefits to you before you decide, and you can withdraw at any time.

The best way to weigh safety for a specific study is to read the participant information sheet carefully, ask the research team questions and talk it through with your own doctor.