Lysergic acid amide (LSA) from Argyreia nervosa seeds, often considered a natural substitute for LSD, shows weak psychedelic activity and should not be regarded as LSD-like. Computer models predicted LSA has highest affinity for α1A and α1B receptors, with clear affinity for several serotonin and dopamine receptors. In lab tests, LSA had lower binding affinities than LSD for all tested receptor subtypes, but showed clear affinity for 5-HT1A, 5-HT2, and α2 receptors. Other ergotalkaloids in the plant also prefer serotonin and dopamine receptors. Vegetative and psychotropic effects may arise from serotonin or dopamine receptor activation, but the psychedelic effect is weak.
The pharmacokinetics of 4-fluoroamphetamine (4-FA) in humans resemble those of amphetamine, with peak serum concentrations occurring about 2 hours after ingestion and an elimination half-life of roughly 8-9 hours, though this varies widely (5.5-16.8 hours). After a 100 mg dose, median maximum serum concentration was 195 ng/mL (range 155-316 ng/mL). Concentrations in oral fluid were higher than in serum, especially during the first 3 hours, likely due to oral contamination. Serum concentrations observed in forensic cases matched those in the study, suggesting recreational doses are similar, but such doses may already cause prominent adverse effects and life-threatening consequences.