I wanted to write this experience report because I have never seen any documentation of addiction to research chemical (halogenated) amphetamines. Not a single forum post or report that someone was hooked on this dirty halogenated amphetamine class like I was. So I figured I'd tell my story.
4-FMA
Well-documented
Well-documented
Multiple authoritative sources agree on dosing and effects.
- 3 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 20 combo interactions documented
- toxicity data (PsychonautWiki)
- classified Research-chemical
Well-documented
Multiple authoritative sources agree on dosing and effects.
- 3 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 20 combo interactions documented
- toxicity data (PsychonautWiki)
- classified Research-chemical
Aliases: 4-fluromethamphetamine, 4fma
Summary
4-Fluoromethamphetamine (also known as 4-FMA) is a lesser-known novel stimulant-entactogen substance of the amphetamine class. 4-FMA is chemically related to 4-FA and methamphetamine. Little is known about its pharmacology, but it likely produces its effects by increasing levels of dopamine, norepinephrine, and serotonin in the brain.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral | 25-50mg | 50-75mg | 100-125mg | 125mg+ |
Light
Common
Strong
Heavy
Sources
Oral
Dose ladder — dose.wiki, PsychonautWikiOnset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 18-42 min | 18-42 min | 2-5 hrs | 1-2 hrs | 3-5 hrs |
Effect Profile
1 reportsScores (0–10) curated from multiple sources:
- Effect keyword matching from PsychonautWiki catalog
- Weighted by importance: core (×3), major (×2), minor (×1)
Empathogen
6.1
Strong
6/10
Strong euphoria with moderate stimulation, mild empathy, low sensory enhancement
Empathy / Social Openness
×3
5
empathy, affection and sociability enhancement
increased sociability
Euphoria / Mood Elevation
×2
10
physical euphoria
euphoria
cognitive euphoria
mood lift
Stimulation
×1
7
stimulation
wakefulness
teeth grinding
increased heart rate
Sensory Enhancement
×1
1
increased libido
Stimulant
5.9
Strong
6/10
Strong euphoria with strong anxiety/jitters, moderate focus, mild stimulation
Stimulation / Energy
×3
5
stimulation
wakefulness
Euphoria / Mood Lift
×2
10
physical euphoria
euphoria
cognitive euphoria
mood lift
motivation enhancement
Focus / Productivity
×2
6
analysis enhancement
motivation enhancement
thought acceleration
Anxiety / Jitters
×1
10
anxiety
paranoia
bruxism
increased heart rate
teeth grinding
vasoconstriction
+1 more
Based on reports from:
Tolerance
Build-up
develops over days to weeks of regular use
Reset
3–7 days for acute; 1–3 weeks for full reset
Tolerance Decay
Full tolerance
1d
Half tolerance
12d
Baseline
~21d
Cross-Tolerances
Empathogens
Effects
Effect glossary — · full glossary
Positive
Negative
Positive
Negative
Positive
Negative
- Visual and auditory hallucinations
Combinations
Cross-Check 4-FMA with another substanceCommunity Trip Reports
Anecdotal first-person accounts from Reddit, Erowid, Bluelight, and Dose.wiki. Click a source to expand. Reports are harm-reduction context, not medical guidance. Tags summarise each author's own verdict — how reports are classified.
Erowid 2 reports 1 neutral 1 cautionary visit
Well would only be fair to share some background for reference. now I am 25 used extensively psycho actives, from pharms to rcs to natural to all others. basically its my biggest hobby and has been going strong since day one.
Bluelight 1 thread 1 positive visit
I have used 4-FMA a lot as it's a higher quality amphetamine and provides a great amphetamine high with a MDMA like buzz to it. I waited until 1pm and I dropped 125mg my ideal dose.
4-FMA's nerd page
Pharmacology, chemical data, effect profiles, and more
→
Helpful Links
Import into PsychonautWiki Journal
The PsychonautWiki Journal app includes 4-FMA, but its built-in data can be thinner than ours. Importing this file adds a separate "4-FMA (Substance Search)" custom substance with our dose ranges, durations and tolerance, so you can log against whichever you prefer.
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Import this file as custom substances
and you get "4-FMA (Substance Search)" with every
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developer.
Ranges are harm-reduction guidance, not a prescription.
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