buy 4 FA (4-FLUOROAMPHETAMINE), also called 4-FA or para-fluoroamphetamine (the position where fluorine is called the 4 or para position) is a synthetic drug with stimulating and empathogenic effects. Its chemical structure is very close to the amphetamine molecule, differing from it only with the presence of a fluorine atom in position 4 (para) of the phenyl ring. It is also very close to 4-chloroamphetamine, a highly neurotoxic amphetamine, differing from it only with the presence of a chlorine atom instead of a fluorine atom.
Like amphetamine, 4-fluoroamphetamine works by inhibiting the reuptake of dopamine and norepinephrine in the brain. But unlike amphetamine,
buy 4 FA (4-FLUOROAMPHETAMINE) inhibits serotonin reuptake much more pronounced. The few studies done on this compound suggest that it has nothing to do with its neurotoxic halogenated analogues: 4-chloroamphetamine, 4-bromoamphetamine and 4-iodoamphetamine. It has indeed a lower potency and does not cause a depletion of serotonin stocks. However, it would have been logical to think that 4-fluoroamphetamine is the most neurotoxic of the halogenated amphetamines since the neurotoxicity increases as it descends the halogen column to chlorine. But it is not, 4-FA is different from other halogenated amphetamines. No doubt this is due to the bond strength between the fluorine atom and the phenyl ring and / or a matter of metabolism.
The subjective effects of 4-fluoroamphetamine include euphoria which some find similar to the effects of MDMA and amphetamine,  increased energy (stimulation), mood elevation, feelings of warmth and empathy, excessive talking, bruxism, and suppressed appetite (anorexic) . The general course of effects involves primarily empathogenic effects for the first few hours, which fades out as increased stimulation develops over the next several hours
A does not cause long-lasting depletion of brain serotonin, unlike its analogs 4-CA and 4-BA. This is thought to “reflect the inability of the fluoro-compound to be metabolized in the same way as the other haloamphetamines.”
Neurotoxicity does not increase down the series of para-halogenated amphetamine derivatives, even though serotonin releasing potency does follow this trend. For example, 4-iodoamphetamine is less toxic than is 4-chloroamphetamine. Hence, this property is not related to serotonin releasing potency as such, since PAL-287 was reported to be not at all neurotoxic even though it is a powerful 5-HT releasing agent. It is unclear where buy 4 FA (4-FLUOROAMPHETAMINE) fits in on the neurotoxicity scale. The extensive serotonergic neurotoxicity of 4-chloroamphetamine (and its brominated derivative), and the increased serotonergic toxicity of 4-methylamphetamine suggest that para-substitution seems to increase overall serotonergic (neuro)toxicity, compared to amphetamine. Exceptions include 4-MTA, a para-substituted, non-neurotoxic amphetamine.