FP-LAD

FP-LAD, also known as fluoro-PRO-LAD or as TRALA-16, is a serotonin receptor modulator of the lysergamide family related to lysergic acid diethylamide (LSD; METH-LAD).^[1] It is specifically a fluorinated derivative of PRO-LAD (6-propyl-6-nor-LSD) and an analogue of FLUORETH-LAD (FE-LAD; 6-ethyl-6-nor-LSD).^[1]

Other namesFluoro-PRO-LAD; F-PRO-LAD; Fluoropropyl-LAD; TRALA-16; 6-(3-Fluoropropyl)-6-nor-LSD; (8β)-N,N-Diethyl-6-(3-fluoropropyl)-9,10-didehydroergoline-8-carboxamide

Drug classSerotonin receptor modulator; Serotonin 5-HT_2A receptor agonist

ATC code

• None

PubChem CID

• 166091994

Quick facts Clinical data, Other names ...

FP-LAD

Clinical data
Other names	Fluoro-PRO-LAD; F-PRO-LAD; Fluoropropyl-LAD; TRALA-16; 6-(3-Fluoropropyl)-6-nor-LSD; (8β)-N,N-Diethyl-6-(3-fluoropropyl)-9,10-didehydroergoline-8-carboxamide
Drug class	Serotonin receptor modulator; Serotonin 5-HT2A receptor agonist
ATC code	None
Identifiers
IUPAC name (6aR,9R)-N,N-diethyl-7-(3-fluoropropyl)-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
PubChem CID	166091994
Chemical and physical data
Formula	C22H28FN3O
Molar mass	369.484 g·mol−1
3D model (JSmol)	Interactive image
SMILES CCN(CC)C(=O)[C@H]1CN([C@@H]2CC3=CNC4=CC=CC(=C34)C2=C1)CCCF
InChI InChI=1S/C22H28FN3O/c1-3-25(4-2)22(27)16-11-18-17-7-5-8-19-21(17)15(13-24-19)12-20(18)26(14-16)10-6-9-23/h5,7-8,11,13,16,20,24H,3-4,6,9-10,12,14H2,1-2H3/t16-,20-/m1/s1 Key:BFFBEQKSDONILF-OXQOHEQNSA-N

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The drug has been reported to act as a potent ligand of the serotonin 5-HT₂ receptors.^[1] It had affinities (K_i) of 0.93 nM at the serotonin 5-HT_2A receptor, 1.8 nM at the serotonin 5-HT_2B receptor, and 3.7 nM at the serotonin 5-HT_2C receptor.^[1] FP-LAD was assessed and found to be a full agonist of the serotonin 5-HT_2A and 5-HT_2C receptors, with EC₅₀Tooltip half-maximal effective concentration and E_maxTooltip maximal efficacy values of 0.48 nM (93%) and 1.7 nM (97%), respectively.^[1] It had several-fold greater activational potency than LSD at the serotonin 5-HT_2A and 5-HT_2C receptors.^[1]

The chemical synthesis of FP-LAD has been described.^[1]

FP-LAD was patented by Daniel Trachsel and Matthias Liechti and colleagues in association with MindMed (Mind Medicine) in 2023.^[1] It had also previously been described in an earlier patent by Andrew Kruegel in association with Gilgamesh Pharmaceuticals in 2022.^[2] Hamilton Morris has described synthesizing FP-LAD and/or 1P-FP-LAD with Lizard Labs in 2025.^[3][4][5] According to Morris, FP-LAD was active but had only about one-fifth of the potency of LSD.^[5]