LAE-32, or lysergic acid monoethylamide, is a lysergamide in which the amide nitrogen carries one ethyl group and one hydrogen. It is chemically distinct from LSD, which has two ethyl groups, and from LSA (ergine), which has an unsubstituted primary amide. LAE-32 was investigated in European psychiatric research during the 1950s, where it was described as having a more sedative profile than LSD.
Chemistry and naming
LAE-32 is also called lysergic acid ethylamide or lysergic acid monoethylamide. Its structure retains the ergoline skeleton of LSD, but one of the two ethyl groups on the carboxamide nitrogen is replaced by hydrogen. This is an amide modification, not a substitution at the indole nitrogen.
The abbreviation can be a source of confusion. Some historical publications used “LSA” loosely when discussing LAE-32, but the name LSA is now commonly used for lysergic acid amide, also known as ergine. The two compounds should be treated separately in chemical and toxicological records.
Historical clinical research
LAE-32 was examined in psychiatric settings in the 1950s. A 1954 Swiss report described it as a new ergot-derived psychotropic compound with sedative properties. An Italian study published in 1955 specifically addressed its psychological effects in humans (Tonini and Montanari, 1955).
Later historical accounts describe trials involving psychiatric patients in which LAE-32 was distinguished from LSD by its stronger sedative action and a different pattern of psychological effects. These studies predate modern clinical-trial standards, and their methods and outcome measures do not support a contemporary assessment of efficacy or safety (D’Arienzo and Samorini, 2023).
Pharmacology
Detailed modern receptor-binding data for LAE-32 are limited. Historical work places it among lysergamides with psychoactive effects, but its activity across 5-HT receptor subtypes remains poorly defined. Its reduced activity relative to LSD in older comparisons should not be interpreted as a simple measure of safety or as proof of a specific receptor mechanism.
Reported effects and research limitations
The most consistent historical distinction is a sedative quality compared with LSD. Beyond that, the clinical descriptions are difficult to compare because the studies were small, conducted in different settings and often involved psychiatric patients rather than healthy volunteers.
There is no modern controlled study establishing LAE-32’s pharmacokinetics, acute toxic range, dependence potential or long-term effects. The historical medical research offers context, without establishing a validated therapeutic profile.
Related lysergamides
LAE-32 is related to LSD, LSA and other lysergic acid amides. It differs from LSD by having a monoethylamide group and from LSA by having one ethyl substituent on the amide nitrogen.
