6-MAM
6-MAM is a unique metabolite of heroin, and its presence is a definitive indication of heroin use. Like heroin, 6-MAM has a very short half-life.
An example of an illicit drug is heroin, which is commonly detected in urine as its unique metabolite 6-monoacetylmorphine (6-MAM) and its major metabolite morphine. Detection of 6-MAM has been considered the definitive evidence of heroin use.