4-FMC
4-FMC is a synthetic stimulant of the substituted cathinone class.citation needed First appearing on the designer drug market in 2008, it was primarily marketed as a replacement for mephedrone. It is reported to produce typical cathinone stimulant effects alongside mild empathogenic properties. As a research chemical, it has limited formal study regarding its safety profile and long-term health effects.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Duration
Subjective Effects
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The experience is that of a typical substituted cathinone stimulant, dominated by euphoria, increased energy and alertness, and a strong drive toward socialization and talking. Mood elevation and increased libido accompany the stimulation, though the emotional tone can become unstable, with moodiness and aggressiveness reported. At heavier use, perceptual disturbances in the form of visual and auditory hallucinations can occur.
Physical
The body load is that of a physical stimulant: increased energy, decreased need for sleep, appetite suppression, sweating, itchiness, and teeth grinding. Disturbed sleep patterns commonly follow use, and weight loss can occur with repeated use.
Stimulation
Physical stimulation is the core of the experience.
Uncomfortable
Cognitive
The headspace is energetic and socially disinhibited, characterized by mood lift, increased sociability, and excessive talking. This can shift into a more negative emotional register, with irritability, moodiness, and aggressiveness reported.
Emotional
The emotional character is predominantly euphoric and mood-lifting, but can turn volatile.
Visual
Visual effects are limited to hallucinations reported at heavy doses; the substance is not otherwise notably visual.
Auditory
Pharmacology
Interactions
An unlisted combination is an unknown one, not a safe one. Check a dedicated combination chart before mixing.
Tolerance
Harm Potential
Addiction & Dependence
Psychological
Classified as habit-forming, suggesting potential for psychological dependence, though detailed characterization is lacking due to the substance's limited research history.
Psychosis Risk
Visual and auditory hallucinations have been reported among the substance's effects, though the frequency and clinical significance of these perceptual disturbances remain poorly characterized.citation needed
History & Culture
Flephedrone first appeared on the recreational drug market in 2008, where it was sold online as a designer drug.citation needed It was marketed primarily as a replacement for mephedrone, which was gaining popularity during the same period. The substance represents one of the earlier synthetic cathinones to emerge in the designer drug marketplace, and its appearance prompted rapid regulatory responses across multiple jurisdictions, with Denmark becoming one of the first countries to prohibit it by the end of 2008.
Legality
By Country
References
Source Pages
Citations
- Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026. legislation.gov.au (n.d.). https://www.legislation.gov.au/F2026L00633/asmade/2026-05-28/text/original/epub/OEBPS/document_1/document_1.html1
- RIS: Neue-Psychoaktive-Substanzen-Verordnung (NPSV), consolidated text. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/GeltendeFassung.wxe?Abfrage=Bundesnormen&Gesetzesnummer=200076421
- RIS: NPSV Anlage II, BGBl. II Nr. 106/2024. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/Dokumente/Bundesnormen/NOR40261441/II_106_2024_Anlage_II.pdf1
- RIS: Neue-Psychoaktive-Substanzen-Gesetz (NPSG), consolidated text. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/GeltendeFassung.wxe?Abfrage=Bundesnormen&Gesetzesnummer=200076051
- Agência Nacional de Vigilância Sanitária (ANVISA). (2017-06-02). Resolução da Diretoria Colegiada - RDC nº 159, de 02/06/2017. Agência Nacional de Vigilância Sanitária. https://anvisalegis.datalegis.net/action/ActionDatalegis.php?acao=abrirTextoAto&link=S&tipo=RDC&numeroAto=00000159&seqAto=000&valorAno=2017&orgao=RDC/DC/ANVISA/MS&cod_modulo=310&cod_menu=94281
- Measures for the Regulation of Non-medicinal Narcotic Drugs and Psychotropic Substances, supplementary controlled-substances list. gaj.panjin.gov.cn (n.d.). https://gaj.panjin.gov.cn/2015_10/08_00/content-235605.html1
- Bekendtgørelse om euforiserende stoffer, BEK nr 405 (Retsinformation). retsinformation.dk (n.d.). https://www.retsinformation.dk/eli/lta/2026/405/pdf1
- Finlex current consolidated Government Decree 1130/2014. opendata.finlex.fi (n.d.). https://opendata.finlex.fi/finlex/avoindata/v1/akn/fi/act/statute-consolidated/2014/1130/fin@latest1
- Finlex current consolidated annex to Government Decree 1130/2014. opendata.finlex.fi (n.d.). https://opendata.finlex.fi/finlex/avoindata/v1/akn/fi/act/statute-consolidated/2014/1130/fin@latest/media/8500.pdf1
- Finlex official PDF, Government Decree 650/2026. finlex.fi (n.d.). https://www.finlex.fi/api/media/statute/1073201/mainPdf/main.pdf?timestamp=2026-07-01T04%3A45%3A50.635Z1
Further Reading
Banks et al. (2015) - Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs
Eshleman et al. (2013-2017) - In vitro transporter assays of synthetic cathinones- Freeman, S. et al. (2012) "Analytical characterization and in vitro toxicity of 4-fluoromethcathinone"
Simmler et al. (2013) - Pharmacological characterization of designer cathinones
Strano-Rossi et al. (2014) - Immunoassay screening and LC-HRMS analysis of cathinones
Article Status
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Recent changes7 human edits · latest
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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