It is not uncommon for such studies to require that you have blood samples taken on a regular basis, and some trials may also require stool samples, sputum samples, bone-marrow testing, and other laboratory tests. Although the list of disadvantages is longer than the list of advantages, this does not mean that the scales usually tip against joining a trial. What this does mean is that entering a clinical trial is not a decision that should be taken lightly. Don't sign up on the spur of the moment. Talk your options over with your regular healthcare providers, and listen carefully to their advice.
Clinical trials can be inconvenient.
They usually require extra visits to the doctor's office or to a clinic or hospital. Some may even require you to be admitted to the hospital for a time. Be sure to ask if any of these costs are covered by the trial. Next, you should discuss the pros and cons of participation with the researchers who are conducting the trial. Last but certainly not least, ask yourself if you are absolutely certain that you are willing and able to fulfill the requirements of participation before you sign up.