4-Fluoroamphetamine (4-FA; 4-FMP; PAL-303; “Flux“), also known as para-fluoroamphetamine (PFA) is a psychoactive research chemical of the phenethylamine and substituted amphetamine chemical classes. It produces stimulant and entactogenic effects, and is described subjectively as being between amphetamine and MDMA. As a recreational drug, 4-FA is sometimes sold along with related compounds such as 2-fluoroamphetamine and 4-Fluoromethamphetamine
Anecdotal reports have described the subjective effects of 4-FA as having a moderate MDMA-like entactogenic onset for the initial few hours of the experience that then gradually transitions into traditional amphetamine-type stimulation (for a total duration of around 6 to 8 hours) with residual effects that can last a few hours afterward.
4-FA is rarely found on the streets but commonly sold as a grey area research chemical by online vendors along with related compounds such as 2-FMA and 3-FA. Very little data exists about the pharmacological properties, metabolism, and toxicity of 4-FA, and it has only a brief history of human usage. Due to its strong psychostimulant effects, likely habit-forming properties as well as poorly understood toxicity profile, it is strongly recommended that one use proper harm reduction practices if choosing to use this substance.
4-Fluoroamphetamine (4-FA) is a synthetic molecule of the amphetamine family. Molecules of the amphetamine class contain a phenethylamine core featuring a phenyl ring bound to an amino (NH2) group through an ethyl chain with an additional methyl substitution at Rα. Amphetamines are alpha-methylated phenethylamines. 4-fluoroamphetamine contains a fluorine atom at R4 of its phenyl ring and is a fluorinated analogue of amphetamine.
4-Fluoroamphetamine acts as a releasing agent and reuptake inhibitor of dopamine, serotonin, and norepinephrine producing stimulating amphetamine-like effects at lower doses and euphoric, entactogenic effects similar to MDMA at dosages above 100mg. The mechanism of action of 4-FA effectively boosts the levels of the norepinephrine, dopamine, and serotonin neurotransmitters in higher doses in the brain by binding to and partially blocking the transporter proteins that normally remove those monoamines from the synaptic cleft. This allows dopamine, norepinephrine, and serotonin to accumulate within the brain, resulting in stimulating, euphoric and entactogenic effects.