Short answers, pulled from the story.
Albert Hofmann, a Swiss chemist at Sandoz Laboratories in Basel, Switzerland, first synthesized LSD on the 16th of November 1938. It was the 25th compound he produced in a research program on ergot alkaloid derivatives. Hofmann discovered its psychedelic effects five years later, in 1943, after accidental ingestion followed by the first intentional self-experiment on the 19th of April 1943, when he took 250 micrograms.
LSD is extraordinarily potent, producing noticeable effects at doses as low as 20 micrograms, roughly one two-hundredth the mass of a grain of sand. It is approximately 200 times as potent as psilocybin and 5,000 times as potent as mescaline by weight. The typical dose for a full psychedelic experience is around 100 micrograms.
LSD binds with high affinity to most serotonin receptors, especially the 5-HT2A receptor, whose activation is thought to produce the psychedelic effects. It also binds dopamine receptors, which appears to generate a two-phase experience: an initial psychedelic phase and a later paranoia-like phase four to six hours after administration. Neuroimaging studies show LSD reduces the thalamus's ability to filter sensory information and decreases activity in the default mode network.
LSD is widely considered non-addictive; attempts to train laboratory animals to self-administer it have largely failed, and no withdrawal syndrome has been observed. No toxicity-related deaths from LSD at typical recreational doses have been documented despite many millions of exposures. The estimated lethal dose in humans is approximately 100 milligrams, about 1,000 times a standard recreational dose of 100 micrograms.
Project MKUltra was a covert CIA research program launched in the 1950s. The CIA purchased the entire world supply of LSD for $240,000 and distributed it to American hospitals, clinics, prisons, and research centers, conducting experiments on subjects that usually included no informed consent. The program was revealed in the 1975 Rockefeller Commission report, but acting CIA director Richard Helms had destroyed many key documents in 1973.
LSD has been classified as a Schedule I controlled substance in the United States since 1970 and under the United Nations Convention on Psychotropic Substances since 1971. In 2024, the U.S. Food and Drug Administration designated LSD (code names MM120 and DT120) as a breakthrough therapy for generalized anxiety disorder. Oregon decriminalized personal possession of small amounts of LSD in February 2021 after voters approved Ballot Measure 110 in November 2020.