4-FMA
1-(4-fluorophenyl)-N-methylpropan-2-amine
Overview
4-FMA belongs to Entactogens/Empathogens / Phenethylamines.
Key safety note: 4-FMA has been sold as a designer drug but is very poorly characterised.[2]
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.
- Broadly a stimulant experience: increased energy, stimulation and euphoria, with some entactogenic character expected from its releaser profile.
- Human data are very limited: onset, intensity and duration are not reliably documented, and 4-FMA is often encountered mis-sold or as an adulterant in other products.
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.
Not reported
Dose ranges
Duration
Chemical & Physical Properties
| Formula | C10H14FN |
| Molar mass | 167.22 g/mol |
| State | Solid (usually the hydrochloride salt) |
| Melting point | Not reported |
| Boiling point | Not reported |
| Density | Not reported |
| Vapor pressure | Not reported |
| pKa | Not reported |
| LogP | 2.2 (predicted, XLogP3) |
| Solubility | Not reported |
| Refractive index | Not reported |
Identifiers & Synonyms
| CAS | 351-03-1 |
| CAS (enantiomer) | |
| PubChem CID | 11745017 |
| InChIKey | YCWZPIHKUYZTFM-UHFFFAOYSA-N |
| InChI | InChI=1S/C10H14FN/c1-8(12-2)7-9-3-5-10(11)6-4-9/h3-6,8,12H,7H2,1-2H3 |
| SMILES | CC(CC1=CC=C(C=C1)F)NC |
Synonyms
- 4-FMA
- 4-Fluoro-N-methylamphetamine
- para-Fluoromethamphetamine
Pharmacodynamics & Biochemistry
4-Fluoromethamphetamine (4-FMA) is the N-methyl homologue of 4-fluoroamphetamine (4-FA) and the 4-fluoro analogue of methamphetamine. It is reported to act as a monoamine (serotonin–noradrenaline–dopamine) releasing agent, giving stimulant and mild entactogen-type effects, but its pharmacology has been only sparsely characterised and quantitative transporter potencies are not established. Notably, 4-FMA is reported to inhibit cytochrome P450: it slows the metabolism of methamphetamine (and, by extension, other CYP substrates), which can raise their potency, duration and systemic toxicity: a pharmacokinetic interaction of practical concern.
Biological targets
- DAT
- NET
- SERT
Binding & functional measurements
| Target | Measurement | Species |
|---|---|---|
| SERT | Unspecified Monoamine releaser (potency not established) | |
| NET | Unspecified Monoamine releaser (potency not established) | |
| DAT | Unspecified Monoamine releaser (potency not established) |
Pharmacokinetics
| Bioavailability | Oral (not quantified) |
| Tmax | Not established |
| Half-life | Not established in humans |
| Vd | Not reported |
| Protein binding | Not reported |
| Metabolism | Hepatic. 4-FMA is itself a reported CYP450 inhibitor (slows methamphetamine metabolism) |
| Excretion | Renal (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
4-FMA has been sold as a designer drug but is very poorly characterised. It has never been properly studied in humans, so its toxicology and safe-dose range are genuinely unknown. As a stimulant monoamine releaser it should be assumed to carry the usual sympathomimetic risks (raised heart rate and blood pressure, hyperthermia, insomnia, anxiety and a comedown), and, like its analogue 4-FA, potential cardiovascular strain. A specific concern is its CYP450 inhibition: combined with methamphetamine or other CYP-metabolised drugs it can increase their blood levels, effects and toxicity. Missing data must never be read as evidence of safety.[2]
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: Not federally scheduled. UK: Class A. DE: BtMG Anlage II
Interactions & Contraindications
Drug interactions
CYP2D6 substrate drugs 4-FMA inhibits CYP450 and can slow the metabolism of methamphetamine and other substrates, raising their levels, effects and toxicity.[2]
MAOIs Risk of hypertensive crisis and serotonin toxicity.[2]
Stimulants (amphetamines, cocaine), Other serotonergic drugs Additive cardiovascular strain and serotonin-toxicity risk.[2]
Contraindications
Cardiovascular disease, hypertension or arrhythmia or hypertension.
Concurrent MAOI, SSRI/SNRI or other serotonergic medication concurrent MAOIs, methamphetamine or other CYP450-metabolised stimulants.[2]
Personal or family history of psychosis, schizophrenia or bipolar disorder
Pregnancy or breastfeeding
No interactions or contraindications listed.
Usage & Context
- A designer drug / research chemical first detected in 'legal high' products in Japan around 2006 and later sold internationally as a party-pill ingredient.
- Frequently confused with or mis-sold as related fluoro-methamphetamines (e.g. 2-FMA). Little studied and never used medically.
Sources & Evidence
- PubChem: 4-Fluoromethamphetamine (CID 11745017) — identifiers & computed properties
- Wikipedia: 4-Fluoromethamphetamine — pharmacology, history & legal status CC BY-SA 4.0
- DEA Diversion Control Division: Controlled Substance Schedules (4-FMA — not scheduled, Federal Analogue Act may apply)
- GOV.UK: Controlled drugs list (Misuse of Drugs legislation) — 4-FMA is Class A OGL v3.0
- PubChem computed properties (CID 11745017)