LSD
(6aR,9R)-N,N-diethyl-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
Overview
LSD belongs to Psychedelics / Ergolines.
Effects
Subjective effects vary. What a substance feels like depends on dose, individual physiology,
mindset, and setting. The points below describe commonly reported effects, not guaranteed, uniform, or
desirable outcomes.
- Geometry & patterns (drifting patterns, geometric distortion)
- Colour intensification
- Time & space distortion
- Mood amplification (euphoria or anxiety depending on dose, set and setting)
- Introspection
- Associative thinking
- Ego dissolution
Dosing & duration
Harm-reduction note: These are commonly cited reference ranges, not a recommendation or a
“safe” dose. Potency, purity, body chemistry, tolerance, and drug combinations vary widely. Start
low, go slow, wait for full effects before redosing, and never assume an unknown product matches these
figures. Missing data is not evidence of safety.
Oral, Sublingual. Usually blotter, liquid drops, or gel tabs. Strength per tab varies widely: assume an unknown product does not match these figures.
Dose ranges
Threshold
15 µg
Light
15–75 µg
Common
75–150 µg
Strong
150–300 µg
Heavy
300 µg +
Duration
onset
15–30 min
peak
3–5 h
total
8–12 h
after effects
12–48 h
Chemical & Physical Properties
| Formula | C20H25N3O |
| Molar mass | 323.44 g/mol |
| State | Not reported |
| Melting point | 82.5 °C |
| Boiling point | Not reported |
| Density | Not reported |
| Vapor pressure | Not reported |
| pKa | 7.8 |
| LogP | 2.95 |
| Solubility | Water soluble |
| Refractive index | Not reported |
Identifiers & Synonyms
| CAS | 50-37-3 |
| CAS (enantiomer) | |
| PubChem CID | 5761 |
| InChIKey | VAYOSLLFUXYJDT-RDTXWAMCSA-N |
| InChI | InChI=1S/C20H25N3O/c1-4-23(5-2)20(24)14-9-16-15-7-6-8-17-19(15)13(11-21-17)10-18(16)22(3)12-14/h6-9,11,14,18,21H,4-5,10,12H2,1-3H3/t14-,18-/m1/s1 |
| SMILES | CCN(CC)C(=O)[C@H]1CN([C@@H]2CC3=CNC4=CC=CC(=C34)C2=C1)C |
Synonyms
- Lysergide
- Acid
- (+)-lysergic acid diethylamide
- N,N-diethyllysergamide
- Lucy
Pharmacodynamics & Biochemistry
LSD is a potent semi-synthetic ergoline psychedelic, active in the microgram range. Its psychedelic effects depend strongly on serotonin 5-HT2A receptor activation and can be blocked by the 5-HT2A antagonist ketanserin. Binding affinity and measured agonist efficacy vary with the receptor preparation and assay. It is highly promiscuous, binding with high affinity across most serotonin receptors (5-HT1A/1B/1D/2A/2B/2C/5/6/7) and at dopamine D1–D5 and α/β-adrenergic receptors: a breadth that sets it apart from more selective psychedelics and contributes to its complex effects. Dopamine D2 signalling has been implicated in the later phase of the experience. A 2017 crystal structure of LSD bound to the human 5-HT2B receptor showed an extracellular-loop 'lid' over the binding pocket. Companion in vitro experiments at 5-HT2A and 5-HT2B linked this loop to slow dissociation. These findings suggest a contribution of receptor residence time to LSD's prolonged action, but do not by themselves establish the cause of its duration in humans.
Biological targets
- 5-HT2A
- 5-HT1A
- 5-HT2C
- D2
Binding & functional measurements
| Target | Measurement | Species |
|---|---|---|
| 5-HT2A receptor | Ki 15 ± 4.2 nM | Human |
| 5-HT1A receptor | Ki 9.5 ± 3.3 nM | Human |
| 5-HT2C receptor | Ki 45 ± 16 nM | Human |
| 5-HT6 receptor | pKi 8.4 | Human |
| 5-HT6 receptor | pKi 8.25 | Rat |
| 5-HT1A receptor | Ki 2.5 nM | Pig |
| 5-HT2A receptor | EC50 1.5 nM Emax 94 ± 1% | Human |
| 5-HT2A receptor | EC50 4.3 nM Emax 86 ± 3% | Mouse |
| 5-HT2B receptor | EC50 15 nM Emax 78 ± 2% | Human |
| 5-HT2C receptor | EC50 35 nM Emax 82 ± 3% | Human |
| D1 receptor | Ki 87 nM | Unspecified |
| D2 receptor | Ki 155 nM | Unspecified |
| D3 receptor | Ki 65 nM | Unspecified |
| D4 receptor | Ki 30 nM | Unspecified |
| α1-adrenoceptor | Ki 60 nM | Unspecified |
Pharmacokinetics
| Bioavailability | Not reported |
| Tmax | text: ≈1.4–1.7 h (oral). low: 1.4. high: 1.7. unit: h. approx: true |
| Half-life | text: ≈3–6 h plasma. low: 3. high: 6. unit: h. approx: true. note: slower terminal elimination also reported |
| Vd | Not reported |
| Protein binding | Not reported |
| Metabolism | major metabolite O-H-LSD (2-oxo-3-hydroxy-LSD), hepatic via CYP450 |
| Excretion | ≈1% unchanged in urine over 24 h. ≈13% as O-H-LSD over 24 h |
Toxicology & Safety
Harm-reduction note: Toxicity and risk depend on dose, route, purity, combinations, setting, and individual
health factors. Missing harms should never be interpreted as evidence of safety.
12 mg/kg (mouse, i.v.)
LSD has relatively low acute physiological toxicity in studied settings and low dependence liability. A human lethal dose has not been established, which does not establish a safe dose or exclude serious harm. Its main risks are psychological and behavioural: acute anxiety, confusion or panic ('bad trips'), and, less often, persistent effects such as hallucinogen-persisting perception disorder (HPPD) or, in vulnerable people, a prolonged psychotic or manic episode. Because it is so potent and street blotter strength is unpredictable, accidentally taking too much is easy. The most dangerous well-documented drug interaction is with lithium, which is linked to seizures and severe reactions. As an ergoline it is mildly vasoconstrictive. Limited data must never be read as evidence of safety.[4][3]
Legal Status
Legal note: Legal status can change over time and may vary by country, region, formulation, analogue status,
prescription context, and enforcement practice. Always confirm with current official sources before relying on this section.
US: Schedule I. UK: Class A. DE: BtMG Anlage I
Interactions & Contraindications
Drug interactions
Lithium Seizures and severe adverse reactions, one of the most serious documented psychedelic drug interactions.[4]
SSRIs, SNRIs, MAOIs Chronic use generally blunts or abolishes the subjective effects through serotonergic adaptation.[4]
Other serotonergic drugs, Stimulants (amphetamines, cocaine) Additive serotonergic and sympathomimetic load, for example tramadol, other psychedelics and high-dose stimulants.
Contraindications
No interactions or contraindications listed.
Usage & Context
- Recreational and self-exploratory use as a classic psychedelic (blotter, liquid drops or gel tabs).
- A major subject of renewed clinical research into serotonergic psychedelics for depression, anxiety and other conditions.
- Historically central to 1950s–60s psychiatry and neuroscience research before prohibition.
Sources & Evidence
- PubChem: Lysergide / LSD (CID 5761), identifiers & experimental properties
- Wikipedia: Lysergic acid diethylamide (LSD) CC BY-SA 4.0
- Nichols DE (2016). Psychedelics. Pharmacol Rev 68:264-355.
PMID 26841800 · doi:10.1124/pr.115.011478
- Passie T, Halpern JH, Stichtenoth DO, et al. (2008). The pharmacology of lysergic acid diethylamide: a review. CNS Neurosci Ther 14:295-314.
PMID 19040555 · doi:10.1111/j.1755-5949.2008.00059.x
- Dolder PC, Schmid Y, Haschke M, et al. (2015). Pharmacokinetics and concentration-effect relationship of oral LSD in humans. Int J Neuropsychopharmacol 19:pyv072.
PMID 26108222 · doi:10.1093/ijnp/pyv072
- Dolder PC, Schmid Y, Steuer AE, et al. (2017). Pharmacokinetics and pharmacodynamics of lysergic acid diethylamide in healthy subjects. Clin Pharmacokinet 56:1219-1230.
PMID 28197931 · doi:10.1007/s40262-017-0513-9
- Holze F, Vizeli P, Ley L, et al. (2021). Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects. Neuropsychopharmacology 46:537-544.
PMID 33059356 · doi:10.1038/s41386-020-00883-6
- Wacker D, Wang S, McCorvy JD, et al. (2017). Crystal structure of an LSD-bound human serotonin receptor. Cell 168:377-389.e12.
PMID 28129538 · doi:10.1016/j.cell.2016.12.033
- Almaula N, Ebersole BJ, Zhang D, et al. (1996). Mapping the binding site pocket of the serotonin 5-HT2A receptor: Ser3.36(159) provides a second interaction site for the protonated amine of serotonin but not of LSD or bufotenin. J Biol Chem 271:14672-14675.
PMID 8663249 · doi:10.1074/jbc.271.25.14672
- Nichols DE, Frescas S, Marona-Lewicka D, et al. (2002). Lysergamides of isomeric 2,4-dimethylazetidines map the binding orientation of the diethylamide moiety in the potent hallucinogenic agent N,N-diethyllysergamide (LSD). J Med Chem 45:4344-4349.
PMID 12213075 · doi:10.1021/jm020153s
- Wacker D, Wang C, Katritch V, et al. (2013). Structural features for functional selectivity at serotonin receptors. Science 340:615-619.
PMID 23519215 · doi:10.1126/science.1232808
- Marek GJ, Aghajanian GK (1996). LSD and the phenethylamine hallucinogen DOI are potent partial agonists at 5-HT2A receptors on interneurons in rat piriform cortex. J Pharmacol Exp Ther 278:1373-1382.
PMID 8819525
- Egan CT, Herrick-Davis K, Miller K, et al. (1998). Agonist activity of LSD and lisuride at cloned 5-HT2A and 5-HT2C receptors. Psychopharmacology (Berl) 136:409-414.
PMID 9600588 · doi:10.1007/s002130050585
- Preller KH, Herdener M, Pokorny T, et al. (2017). The fabric of meaning and subjective effects in LSD-induced states depend on serotonin 2A receptor activation. Curr Biol 27:451-457.
PMID 28132813 · doi:10.1016/j.cub.2016.12.030
- DEA Diversion Control Division: Controlled Substance Schedules
- GOV.UK: List of most commonly encountered drugs currently controlled under the misuse of drugs legislation OGL v3.0
- Halberstadt AL, Chatha M, Klein AK, et al. (2020). Pharmacological and biotransformation studies of 1-acyl-substituted derivatives of d-lysergic acid diethylamide (LSD). Neuropharmacology 172:107856.
PMID 31756337 · doi:10.1016/j.neuropharm.2019.107856
- Boess FG, Riemer C, Bös M, et al. (1998). The 5-hydroxytryptamine6 receptor-selective radioligand [3H]Ro 63-0563 labels 5-hydroxytryptamine receptor binding sites in rat and porcine striatum. Mol Pharmacol 54:577-583.
PMID 9730917 · doi:10.1124/mol.54.3.577
- Boess FG, Monsma FJ Jr, Carolo C, et al. (1997). Functional and radioligand binding characterization of rat 5-HT6 receptors stably expressed in HEK293 cells. Neuropharmacology 36:713-720.
PMID 9225298 · doi:10.1016/s0028-3908(97)00019-1
- Paulke A, Kremer C, Wunder C, et al. (2013). Argyreia nervosa (Burm. f.): receptor profiling of lysergic acid amide and other potential psychedelic LSD-like compounds by computational and binding assay approaches. J Ethnopharmacol 148:492-7.
PMID 23665164 · doi:10.1016/j.jep.2013.04.044
- PsychonautWiki: LSD CC BY-SA 4.0
- Pharmacokinetics and Concentration-Effect Relationship of Oral LSD in Humans
- IUPHAR/BPS Guide to PHARMACOLOGY (GtoPdb) CC BY-SA 4.0