Pharmacokinetics
LSD's effects normally last from 6–12 hours depending on dosage, tolerance, body weight and age. The Sandoz prospectus for "Delysid" warned: "intermittent disturbances of affect may occasionally persist for several days." Contrary to early reports and common belief, LSD effects do not last longer than the amount of time significant levels of the drug are present in the blood. Aghajanian and Bing (1964) found LSD had an elimination half-life of only 175 minutes. However, using more accurate techniques, Papac and Foltz (1990) reported that 1 µg/kg oral LSD given to a single male volunteer had an apparent plasma half-life of 5.1 hours, with a peak plasma concentration of 5 ng/mL at 3 hours post-dose.
Read more about this topic: Lysergic Acid Diethylamide