An active dose of MLA-74 in humans is described as being approximately 2mgorally and the drug is said to have about 4 to 5% of thepotency of LSD.[1][2][7][8][9][10][11][12] It is also said to have a fasteronset and shorterduration than LSD.[10][12] For comparison,LAE-32 has a listed dose range of 0.5 to 1.6mg orally, approximately 5 to 10% of the potency of LSD, and is likewise described as faster onset and shorter duration.[1][2][7][8][9][10] MLA-74 is about 8-fold less potent than itsanalogueMLD-41 (1-methyl-LSD).[1] Both MLA-74 and LAE-32 are described as producing LSD-like psychic effects in humans.[10][12] However, they are both described as producing only slight or weakhallucinogenic effects.[13]
MLA-74 shows about 8.35times theantiserotonergic activity of LSD in the isolated ratuterusin vitro and about 70-fold the activity of LAE-32 in thisassay.[1][14][15][12] Unlike LAE-32, MLA-74 is practically devoid ofpyretogenic effects in rabbits and is listed as having 0% of the activity of LSD in this regard.[1][14]
^Rutschmann J, Stadler PA (1978). "Chemical Background". In Berde B, Schild HO (eds.).Ergot Alkaloids and Related Compounds. Handbook of Experimental Pharmacology (HEP). Vol. 49. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 29–85.doi:10.1007/978-3-642-66775-6_2.ISBN978-3-642-66777-0.
^Majrashi M, Ramesh S, Deruiter J, Mulabagal V, Pondugula S, Clark R, et al. (2017). "Multipotent and Poly-therapeutic Fungal Alkaloids of Claviceps purpurea". In Agrawal DC, Tsay HS, Shyur LF, Wu YC, Wang SY (eds.).Medicinal Plants and Fungi: Recent Advances in Research and Development. Medicinal and Aromatic Plants of the World. Vol. 4. pp. 229–252.doi:10.1007/978-981-10-5978-0_8.ISBN978-981-10-5977-3.ISSN2352-6831.Metabolites of methysergide also exhibit pharmacological activity. Methylergometrine (one of methysergide's metabolites) is responsible for methysergide's therapeutic effects regarding migraine treatment (Müller-Schweinitzer and Tapparelli 1986). [...] The systemic availability of methysergide after oral administration is only 13%, due to a high degree of first-pass metabolism by N-1 demethylation to methylergometrine. After oral administration, the plasma concentrations of the metabolite are considerably higher than those of the parent drug, and the area under the plasma concentration curve (AUC) for methylergometrine is more than ten times greater than for methysergide.
^abJacob P, Shulgin AT (1994). "Structure-activity relationships of the classic hallucinogens and their analogs".NIDA Research Monograph.146:74–91.PMID8742795.
^Keup W (1970)."Structure-Activity Relationship among Hallucinogenic Agents".Origin and Mechanisms of Hallucinations. Boston, MA: Springer US. pp. 345–376.doi:10.1007/978-1-4615-8645-6_29.ISBN978-1-4615-8647-0. Retrieved12 October 2025.A relation in the same direction might exist between the two N-monoethyl analogues ALA-10 and MLA-74, if judged by their LD50; both are only slightly psychotomimetic. The unsubstituted N-monoethyl analogue of LSD itself is a weak hallucinogen only [122].
^Doepfner W, Cerletti A (1958). "Comparison of lysergic acid derivatives and antihistamines as inhibitors of the edema provoked in the rat's paw by serotonin".International Archives of Allergy and Applied Immunology.12 (1–2):89–97.doi:10.1159/000228445.PMID13549054.
