[Ziggy Fry]

Erowid LSD Vault : Myth about Permanent Presence (LSD stays in your body/spine/brain forever)

LSD is almost entirely metabolized within a day after ingestion. Since the half-life of LSD is only a few hours, only a very small amount of LSD remains even at the end of the trip, and this is excreted in the urine. All traces are undetectable after several days and are certainly gone entirely within a couple of weeks. As detection technology improves and thresholds drop (it is now possible to detect picograms reliably), the time that incredibly small amounts of it could be detected will extend.

Sin.Ziggy.