In an open label study, both the study participants/patients and the researchers/providers know what drug or treatment the participants are receiving. It’s the opposite of a blinded study, where one or both don’t know whether they are receiving the treatment being tested or a placebo. Open label studies can introduce bias into a study, but they also are sometimes used when it’s too difficult or expensive to disguise a drug, such as one that would be provided intravenously. Open label studies are also sometimes done so that the study can go on longer (patients will be more willing to take a drug for a condition they have if they know it’s the drug and not a placebo), thereby providing more information about effectiveness and safety.
