5-APB

1-(1-benzofuran-5-yl)propan-2-amine

Overview

5-APB belongs to Entactogens/Empathogens / Phenethylamines.

Key safety note: 5-APB carries the serotonergic risks of an MDMA-like releaser: hyperthermia, serotonin toxicity (especially with other serotonergic drugs) and hyponatraemia (dangerously low blood sodium from drinking too much water), which has caused at least one death.[2][3]
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.
  • An MDMA-like entactogen: euphoria, emotional warmth, empathy and sociability with stimulant energy, though often described as somewhat less intense than MDMA.
  • A mild psychedelic/visual component (visual disturbances) can appear, reflecting its serotonin-receptor agonism.
  • Notably long-lasting (≈3–8 hours), with a correspondingly drawn-out comedown.
  • Common unwanted effects mirror MDMA: jaw tension, a raised heart rate and body temperature, anxiety and after-effects.
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. Not a recommendation. 5-APB has never been studied in controlled human trials, so these are only commonly cited recreational ranges. It is more potent and much longer-lasting than MDMA which: together with its 5-HT2B-mediated cardiotoxicity and its hyponatraemia and serotonin-toxicity risks: makes redosing especially dangerous. Note that the hydrochloride salt is about 10% more potent by mass than the succinate.

Dose ranges

Light

≈50–75 mg

Common

≈75–125 mg

Strong

≈125–175 mg

Duration

onset

≈45–90 min

peak

≈2–4 h

total

≈3–8 h

Chemical & Physical Properties
FormulaC11H13NO
Molar mass175.23 g/mol
StateSolid (usually the succinate or hydrochloride salt, the hydrochloride is ~10% more potent by mass)
Melting pointNot reported
Boiling pointNot reported
DensityNot reported
Vapor pressureNot reported
pKaNot reported
LogP2.1 (predicted, XLogP3)
SolubilityNot reported
Refractive indexNot reported
Identifiers & Synonyms
CAS286834-81-9
CAS (enantiomer)
PubChem CID9837232
InChIKeyVKUMKUZDZWHMQU-UHFFFAOYSA-N
InChIInChI=1S/C11H13NO/c1-8(12)6-9-2-3-11-10(7-9)4-5-13-11/h2-5,7-8H,6,12H2,1H3
SMILESCC(CC1=CC2=C(C=C1)OC=C2)N

Synonyms

  • 5-APB
  • 5-(2-Aminopropyl)benzofuran
  • Benzofury
  • Benzo Fury
Pharmacodynamics & Biochemistry

5-APB (5-(2-aminopropyl)benzofuran) is a benzofuran entactogen: the benzofuran analogue of MDA and one of the compounds sold as 'Benzo Fury'. It acts as a serotonin–noradrenaline–dopamine releasing agent (and reuptake inhibitor) with balanced, potent release of all three monoamines (EC50 ≈19 nM serotonin, ≈21 nM noradrenaline, ≈31 nM dopamine), giving MDMA-like entactogenic and stimulant effects. It fully substitutes for MDMA in animal drug-discrimination tests. It is also a direct serotonin-receptor agonist: potent at 5-HT2B (EC50 ≈280 nM) and 5-HT2C, with weaker, low-potency 5-HT2A agonism and 5-HT1A affinity, plus activity at TAAR1, which accounts for the mild 'psychedelic'/visual quality some users report. Its potent 5-HT2B agonism is a specific safety concern: chronic 5-HT2B activation drives cardiac valve disease, as seen with fenfluramine and (with heavy use) MDMA, so repeated 5-APB use is expected to carry a similar cardiotoxic risk.

Biological targets

  • SERT
  • NET
  • DAT
  • 5-HT2B
  • 5-HT2C

Binding & functional measurements

TargetMeasurementSpecies
Serotonin transporterEC50 19 ± 2.0 nM
Emax 104%		Rat
Noradrenaline transporterEC50 21 ± 4.0 nM
Emax 103%		Rat
Dopamine transporterEC50 31 ± 3.0 nM
Emax 103%		Rat
5-HT2BEC50 280 nMHuman
5-HT2CKi 880 nMHuman
5-HT1AKi 3,300 nMHuman
5-HT2AEC50 6,300 nMHuman
TAAR1Unspecified High affinity (mouse/rat TAAR1)Rodent
Pharmacokinetics
BioavailabilityOral
TmaxNot well characterised (onset ≈45–90 min)
Half-lifeNot established in humans (duration ≈3–8 h)
VdNot reported
Protein bindingNot reported
MetabolismHepatic
ExcretionRenal (presumed)
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.

Not reported

5-APB carries the serotonergic risks of an MDMA-like releaser: hyperthermia, serotonin toxicity (especially with other serotonergic drugs) and hyponatraemia (dangerously low blood sodium from drinking too much water), which has caused at least one death. Several deaths, alone and in combination, have been reported. Its long duration (up to ~8 h) encourages redosing and overexertion. The most distinctive concern is its potent 5-HT2B receptor agonism, which, as with fenfluramine and MDMA, is expected to damage heart valves (valvulopathy) with repeated use. It has never been tested in humans and its safety margin is unknown. Missing data must never be read as evidence of safety.[2][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.
Interactions & Contraindications

Drug interactions

MAOIs Serotonin toxicity, potentially life-threatening.[2]
SSRIs, SNRIs, Other serotonergic drugs Serotonin-toxicity risk, other releasers included.[2]
Stimulants (amphetamines, cocaine) Additive cardiovascular strain.[2]
Excess plain water (without electrolytes) Excess plain water without electrolytes carries a hyponatraemia risk, as with MDMA.[2]

Contraindications

Cardiovascular disease, hypertension or arrhythmia[3]
Pre-existing heart-valve disease 5-HT2B-mediated valvulopathy risk.[3]
Concurrent MAOI, SSRI/SNRI or other serotonergic medication concurrent MAOIs or serotonergic medication.[2]
Personal or family history of psychosis, schizophrenia or bipolar disorder
Pregnancy or breastfeeding
Usage & Context
  • Emerged as a 'legal high' / designer drug around 2010–2011, widely sold as 'Benzo Fury' (pellets or powder), often alongside its isomer 6-APB.
  • Originally patented by Eli Lilly in 2000 as a candidate 5-HT2C agonist. Adopted recreationally as an MDMA substitute before being banned across many countries.
Sources & Evidence

Further Information