This provision of the Fifth Amendment is probably the best-known of all constitutional rights, as it appears frequently on television and in movies—whether in dramatic courtroom scenes (“I take the Fifth!”) or before the police question someone in their custody (“You have the right to remain silent. Anything you do say can be used against you in a court of law.”). The right protects a person from being forced to reveal to the police, prosecutor, judge, or jury any information that might subject him or her to criminal prosecution.
Even if a person is guilty of a crime, the Fifth Amendment demands that the prosecutors come up with other evidence to prove their case. If police violate the Fifth Amendment by forcing a suspect to confess, a court may suppress the confession, that is, prohibit it from being used as evidence at trial. The right to remain silent also means that a defendant has the right not to take the witness stand at all during his or her trial, and that the prosecutor cannot point to the defendant’s silence as evidence of guilt.
There are, however, limitations on the right against self-incrimination. For example, it applies only to testimonial acts, such as speaking, nodding, or writing. Other personal information that might be incriminating, like blood or hair samples, DNA or fingerprints, may be used as evidence. Similarly, incriminating statements that an individual makes voluntarily—such as when a suspect confesses to a friend or writes in a personal diary—are not protected.
www.justicelearning.org, The United States Constitution, what it says, what it means, A Hip Pocket Guide (Oxford University Press)