LSD was first synthesized by Albert Hofmann in 1938 from ergotamine, a chemical derived by Arthur Stoll from ergot, a grain fungus that typically grows on rye. The short form "LSD" comes from its early code name LSD-25, which is an abbreviation for the German "Lysergsäure-diethylamid" followed by a sequential number.[4][5] LSD is sensitive to oxygen, ultraviolet light, and chlorine, especially in solution, though its potency may last for years if it is stored away from light and moisture at low temperature. In pure form it is a colorless, odorless, tasteless solid.[6] LSD is typically delivered orally, usually on a substrate such as absorbent blotter paper, a sugar cube, or gelatin. In its liquid form, it can also be administered by intramuscular or intravenous injection. LSD is very potent, with 20–30 µg (micrograms) being the threshold dose. New clinical LSD experiments in humans started in 2009 for the first time in