Would you take another place to see what they say, or are they full of shit too?
"The precise mechanism by which LSD alters perceptions is still unclear. Evidence from laboratory studies suggests that LSD, like hallucinogenic plants, acts on certain groups of serotonin receptors designated the 5-HT2 receptors, and that its effects are most prominent in two brain regions: One is the cerebral cortex, an area involved in mood, cognition, and perception; the other is the locus ceruleus, which receives sensory signals from all areas of the body and has been described as the brain's "novelty detector" for important external stimuli.
LSD's effects typically begin within 30 to 90 minutes of ingestion and may last as long as 12 hours. Users refer to LSD and other hallucinogenic experiences as "trips" and to the acute adverse experiences as "bad trips." Although most LSD trips include both pleasant and unpleasant aspects, the drug's effects are unpredictable and may vary with the amount ingested and the user's personality, mood, expectations, and surroundings."
http://alcoholism.about.com/cs/lsd/f/lsd_faq04.htm
"How long does the feeling last?
The effects of LSD come on gradually within an hour of taking the drug, "peak" at two to four hours and gradually taper off, with the entire trip lasting up to 12 hours. The intensity of the effect depends on the size of the dose.
Some users feel let down or fatigued for 12 to 24 hours after the trip is over. "
http://www.camh.net/About_Addiction_Mental_Health/Drug_and_Addiction_Information/lsd_dyk.html