Clinical Research: Benefits, Risks, and Safety

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If you’re interested in volunteering for clinical research, you may wonder: What makes a study a good fit for me? How do I know it’s safe? Clinical research involves studying health and illness in people through observational studies or clinical trials. Participating in a trial or study has many potential benefits and also some possible risks. Learn about the benefits and risks of participating in clinical research and how your safety is protected.

What are the potential benefits of participating in clinical research?

There are many possible benefits of being part of clinical research, including:

• You may have the chance to help scientists better understand your disease or condition and to advance treatments and ways to prevent it in the future.
• You may feel like you’re playing a more active role in your health.
• You may learn more about your disease or condition.
• You may be able to get information about support groups and resources.

In addition, some people participate in clinical trials because they hope to gain access to a potential new treatment for a disease before it is widely available.

What are the potential risks of participating in clinical research?

Clinical trials and studies do come with some possible risks, including:

• The research may involve tests that pose a risk to participants. For example, certain physical tests may increase the chance of falling, and X-rays may cause a small increase in the risk of developing cancer.
• Participating in a study could also be inconvenient for you. For example, you may be required to have additional or longer medical appointments, more procedures, complex medication instructions, or hospital stays.

Additional risks of participating in clinical trials may include:

• For those who receive the experimental treatment, it may be uncomfortable or cause side effects (which can range from mild to serious).
• The experimental treatment might not work, or it may not be better than the standard treatment.
• For trials testing a new treatment, such as a new medication or device, you may end up not being part of the group that gets the experimental treatment. Instead, you may be assigned to the control (or comparison) group. In some studies, the control group receives a placebo, which is given in the same way as the treatment but has no effect.

Participant confidentiality is a concern in any kind of research. People other than the researchers, such as the study sponsors or experts who monitor safety, may be able to access medical information related to the study. Safeguards are in place to ensure that researchers tell potential participants what information could be shared and how their privacy will be protected before they consent to participate in research.

The study coordinators will provide detailed information and answer questions about the risks and benefits of participating in a particular study. Having this information can help you make an informed decision about whether to participate.

Will I always get the experimental treatment in a clinical trial?

Clinical trial volunteers do not always get the treatment being tested. The gold standard for testing interventions in people is called a randomized controlled trial. Randomized means that volunteers are randomly assigned — chosen by chance — to receive either the experimental intervention (the test group) or a placebo or the current standard care (the control or comparison group). Then, researchers compare the effects in each group to determine whether the new treatment works.

When you enroll in a clinical trial, you may be assigned to the test group or to the control group. While participants in the control group do not receive the experimental treatment, these volunteers are just as important as those in the test group. Without the control group, scientists cannot be sure whether an experimental treatment is better than the standard or no treatment.

In many cases, you won’t know until the end of the trial whether you are in the test group or the control group. That’s because knowing the group assignment might influence the results of the trial. Studies are often “blinded” (or “masked”) to prevent this accidental bias. In a single-blind study, you are not told whether you are in the test group or the control group, but the research team knows. In a double-blind study, neither you nor the research team knows what group you are in until the trial is over. If medically necessary, however, it is always possible to find out which group you are in.

What is a placebo?

Whenever possible, clinical trials compare a new treatment for a specific condition to the standard treatment for that condition. When there is no standard treatment available, scientists may compare the new treatment to a placebo, which looks like the drug or treatment being tested but isn’t meant to actually change anything in your body. A pill that doesn’t contain any medicine is one example.

A trial that uses a placebo is described as a “placebo-controlled trial.” In this type of study, the test group receives the experimental treatment, and the control group receives the placebo.

Placebos are not used if an effective treatment is already available or if you would be put at risk by not having effective therapy. You will be told if placebos are used in the study before entering a trial as part of the process of informed consent.

• What happens if a clinical trial ends early?

  Most clinical trials run as planned from beginning to end. However, sometimes researchers end trials early. Clinical trials may be paused or stopped for a number of reasons:

  • There is clear evidence that one intervention is more effective than another. When this happens, the trial may be stopped so that the new treatment can be made available to other people as soon as possible.
  • The trial shows that the treatment doesn’t work or causes unexpected and serious side effects.
  • The researchers can’t enroll enough people in the trial to provide meaningful results.

  Even when a clinical trial ends early, it can still provide researchers with valuable information. For example, scientists may gain insights about how to best design and conduct clinical trials in a specific research area. In some cases, health information collected during a trial can lead to new potential therapies that researchers can test in the future.

• Where can I find a clinical trial or study?

  Looking for clinical research related to aging and age-related health conditions? There are many ways to find a trial or study. Talk to your health care provider and use online resources to:

  • Search for a clinical trial or study.
  • Look for clinical trials on Alzheimer’s disease, other dementias, and caregiving.
  • Find a registry for a particular diagnosis or condition.
  • Explore clinical trials and studies funded by NIA.

  To learn more about a particular trial or study, you or your doctor can contact the research staff and ask questions. You can usually find contact information in the study description.

For more information about clinical research

This content is provided by the NIH National Institute on Aging (NIA). NIA scientists and other experts review this content to ensure it is accurate and up to date.

Content reviewed: May 18, 2023