Ch. VIII — Fluoroethyl lysergamides

Chapter VIII of Post-2010 Psychedelics: An Expert-Panel Review. For the executive summary and full table of contents, start there.

Abstract. Fluoroethyl lysergamides — principally FLUORETH-LAD (FE-LAD), FP-LAD, and a small set of related fluorinated ergolines — have emerged from grey-market chemistry and patent literature between 2022 and 2025. No clinical trials, formal Phase 1 pharmacokinetic studies, or peer-reviewed in-vivo human safety data exist for any compound in this class as of the freeze date (13 May 2026). This chapter treats the class as a problem in structural pharmacology and harm-reduction epistemology rather than therapeutics: what is known, what is inferred from analogy to LSD, and how the panel should weigh self-experiment and analytical-chemistry reports in the absence of regulated trials.

8.1 Why this chapter exists

Fluoroethyl lysergamides sit awkwardly in a “post-2010 psychedelics” review because they have no clinical evidence base at all — there is no efficacy claim to evaluate, no dose-finding study to interpret, no adverse-event registry to weigh. What exists is (i) a small patent literature describing in-vitro receptor binding and mouse head-twitch potency,¹ (ii) analytical-chemistry papers characterising structurally adjacent N1-acylated lysergamides for forensic purposes,² and (iii) a corpus of grey-market trip reports on PsychonautWiki, Erowid, and BlueLight.³

The argument for including the class is not therapeutic: the post-2010 lysergamide research-chemical wave (1P-LSD, ALD-52, 1cP-LSD, 1V-LSD, ETH-LAD, AL-LAD, and now the fluorinated analogues) reveals how chemistry, regulation, and self-experimentation co-evolve when first-generation prodrug strategies fall under scheduling pressure. The relevant epistemic posture is the one used by analytical toxicologists and harm-reduction researchers — not the one used to evaluate clinical-trial outcomes (Chapter V).

8.2 Lysergamide SAR background and the fluorination strategy

The ergoline scaffold (see Chapter II for full SAR treatment) carries two positions of pharmacological consequence: the indole nitrogen at position 1 (N1) and the basic nitrogen at position 6 (N6). LSD is unsubstituted at N1 and methyl-substituted at N6; substituting these positions changes both 5-HT2A activity and metabolic susceptibility. Two parallel chemistry tracks dominate the post-2010 grey market.

The N1-acylation track produces LSD prodrugs. 1P-LSD, ALD-52, 1cP-LSD, and 1V-LSD share a common pharmacological logic: the N1-acyl group is hydrolysed by serum or hepatic esterases to release LSD itself.⁴⁵ In-vitro incubation of 1cP-LSD with human serum yields LSD, and mouse head-twitch potency tracks equimolar LSD after a short hydrolytic delay.⁴ These compounds are LSD-by-other-means; their structural diversification is regulatory arbitrage, not pharmacological novelty.

The N6-alkylation track produces compounds with intrinsic 5-HT2A activity. The Shulgin-era N6 analogues — ETH-LAD (N6-ethyl), AL-LAD (N6-allyl), PRO-LAD (N6-propyl) — were catalogued in TiHKAL and entered the research-chemical market in the early 2010s. Replacing the N6-methyl with longer or branched alkyl groups modulates receptor affinity and duration without depending on metabolic activation. Fluoroethyl modification fits this second track: a 2-fluoroethyl group at N6 is isosteric with ETH-LAD’s ethyl but introduces a C–F bond whose dipole and metabolic stability alter binding-pocket interactions and oxidative-dealkylation kinetics. The compounds in §8.3–§8.5 are direct 5-HT2A agonists, not LSD prodrugs — their pharmacology must be inferred from in-vitro binding plus rodent head-twitch data, not from LSD-equivalence.

8.3 FLUORETH-LAD (FE-LAD, TRALA-15)

FLUORETH-LAD — systematically 6-(2-fluoroethyl)-6-nor-lysergic acid diethylamide, also designated FE-LAD or TRALA-15, CAS 2757566-18-8 — was first proposed by Alexander and Ann Shulgin in TiHKAL but never synthesised by them.⁶ The first reported synthesis and in-vitro pharmacology appeared in patent WO 2022/008627 A2, filed by Compass Pathfinder Ltd. with Matthias Grill as inventor on 7 July 2021 and published 13 January 2022.¹ The patent’s primary claims cover an improved GMP-compatible LSD synthesis and a broad genus of N1- and N6-modified lysergamides; FLUORETH-LAD sits within the N6-haloalkyl subgenus alongside chloro- and bromo- analogues.

The patent reports FLUORETH-LAD affinity at human 5-HT1A and 5-HT2A comparable to LSD, with substantially reduced affinity at 5-HT2C and at dopamine D1/D2/D4.¹⁶ If those numbers replicate independently, FLUORETH-LAD would have a cleaner 5-HT2A-selective profile than LSD — though selectivity-over-LSD is a modest accomplishment given LSD’s polypharmacology across 5-HT2A/2B/2C, 5-HT1A/1B/1D/6/7, and the dopamine D family. The panel should note: these binding data are from a patent, not a peer-reviewed publication; the Ki and EC50 values, methodology, and replication status have not been journal-reviewed. Patent binding data are routinely optimistic about selectivity. [VERIFY: independent receptor-binding replication of FLUORETH-LAD]

FLUORETH-LAD has appeared on grey-market vendor sites since approximately 2023–2024, typically as low-microgram blotter. No peer-reviewed analytical characterisation paper exists for FLUORETH-LAD specifically as of 2026-05-13 — the Brandt-group “Return of the lysergamides” series covers N1-acyl LSDs (Parts I–VII)²⁴⁵ but has not extended to N6-fluoroalkyl analogues. [VERIFY: any 2025–2026 Brandt-group or equivalent forensic characterisation of FLUORETH-LAD] No in-vivo pharmacokinetic, human safety, or efficacy data exist.

8.4 FP-LAD (PROF-LAD, TRALA-16)

FP-LAD — 6-(3-fluoropropyl)-6-nor-lysergic acid diethylamide, also Fluoro-PRO-LAD, F-PRO-LAD, PROF-LAD, or TRALA-16; PubChem CID 166091994 — is the three-carbon homologue of FLUORETH-LAD: a fluorinated PRO-LAD rather than a fluorinated ETH-LAD. Synthesis and pharmacology are described in patent US 2023/0414583 (“Lysergic acid derivatives with modified LSD-like action”), assigned to MindMed with Trachsel and Liechti as inventors, and in related work from Gilgamesh Pharmaceuticals (Kruegel; WO 2022/226408 A1).⁷ A 2025 independent synthesis by Hamilton Morris with Lizard Labs characterised the compound in vivo (mouse head-twitch) at approximately one-fifth LSD’s milligram potency.⁷

The MindMed patent reports nanomolar agonism at 5-HT2A (EC50 ≈ 0.48 nM, ~93% efficacy), 5-HT2B, and 5-HT2C, with Ki values in the low single-digit nM range across the same panel.⁷ The 5-HT2A potency is reported as several-fold greater than LSD in those assays, although in-vivo milligram potency is lower — a discrepancy consistent with PK dilution (lower bioavailability or shorter half-life) rather than weak target engagement. These numbers come from sponsor-optimised patent assays, not independent peer-reviewed replication. Of the three N6-fluoroalkyl compounds here, FP-LAD has the most pharmacological data because of the MindMed program’s interest in 6-substituted ergolines as differentiated LSD-like therapeutics. No IND filing is on the public record.

8.5 1Fe-LSD and the fluoroethyl/ferrocenyl naming collision

A note of caution: the abbreviation “1Fe-LSD” appears in grey-market and Wikipedia sources and is easily mistaken for “1-fluoroethyl-LSD.” It is not. 1Fe-LSD is 1-(ferrocenecarbonyl)-LSD, also designated SYN-L-234 — an iron-containing organometallic N1-acyl LSD prodrug patented in 2024 by Lizard Labs / Synex Holdings BV (WIPO WO 2024/028495, inventors Stratford and Williamson, filed August 2023, published February 2024).⁸⁹ The orange tint of 1Fe-LSD blotter comes from the ferrocene moiety, not fluorine. 1Fe-LSD is an N1-acyl LSD prodrug in the same logical class as 1P-LSD and 1cP-LSD — not a fluoroalkyl analogue. Treat any source citing “1FE-LSD” as a fluoroethyl analogue with caution: no published N1-fluoroethyl LSD analogue distinct from 1Fe-LSD ferrocene has been reported in the peer-reviewed or patent literature as of the freeze date. [VERIFY: existence of any genuine N1-fluoroethyl LSD analogue] This naming collision is itself an artefact of the grey-market ecosystem — rapid coinage, conflated abbreviations, post-hoc Wikipedia disambiguation — exactly the kind of error a regulatory reader needs flagged.

8.6 Grey-market epistemics

Dominant documentation for subjective effects of FLUORETH-LAD, FP-LAD, and most analogues lives on PsychonautWiki, Erowid, BlueLight, and Reddit subforums. These sources aggregate dose-range estimates from anonymous self-reporters, sometimes correlate batch with reported effects via vendor identification, and document adverse events otherwise invisible. They suffer from selection bias toward enthusiastic reporters, no confirmation of compound identity (most users do not run reagent or analytical tests), no placebo control, and no denominator data — for every “great experience” report there is an unknown number of silent users with null or adverse outcomes.

The self-experimentation tradition runs from Hofmann’s 1943 LSD dose through the Shulgins’ PiHKAL/TiHKAL protocols to today’s chemist–vendor–consumer triad. Structured self-report under known dose and known compound has produced phenomenological observations later replicated in the lab (2C-B, DOM, several N6-alkyl LSD analogues). It is not nothing. But the modern research-chemical ecosystem is more diffuse than Shulgin’s notebooks: compound identity, dose, and purity are estimated rather than known, and the “research” is industrial-scale anonymous distribution, not investigator-supervised study. Treat PsychonautWiki dose ranges as orientation, adverse-event reports as signals to investigate, and any forum-sourced efficacy claim as unevidenced at the level required for a regulatory document.

A specific harm-reduction implication: when users substitute a fluoroalkyl analogue for LSD assuming equivalence, they extrapolate from a single binding number in a patent. Differences in 5-HT2B affinity, half-life, and subtype selectivity could shift cardiotoxicity or duration in ways not predictable from “feels like LSD” reports. Chapter IX returns to the 5-HT2B/valvulopathy question.

8.7 Regulatory status and outlook

The UK Psychoactive Substances Act 2016 captures the entire fluoroethyl-lysergamide class through its blanket prohibition on non-exempt psychoactives. The US Federal Analogue Act allows prosecution of substances “substantially similar” to Schedule I drugs intended for human consumption; FLUORETH-LAD and FP-LAD would almost certainly qualify, but no individual federal scheduling action against these compounds is on record as of 2026-05-13. Germany’s NpSG covers LSD-like structures generically; Switzerland (home of MiHKAL GmbH) controls LSD specifically but treats individual analogues case-by-case.

Expect continued analogue proliferation under N1-acyl and N6-haloalkyl strategies, slow scheduling actions chasing each named compound, and structural drift toward modifications that evade analogue-act language while preserving 5-HT2A agonism. None of this implies clinical development. If any fluoroalkyl lysergamide enters a regulated clinical pipeline in the next few years it would most likely be FP-LAD via MindMed, on the strength of the patent SAR work and the company’s existing LSD-tartrate (MM120) infrastructure for GAD. No such IND filing is public at this time.

References

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