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§2.3.5 · Chemicals › Stimulants

4-FA

4-Fluoroamphetamine

Also known as 4-FMP · PAL-303 · Flux · Flits · R2D2 · PFA

Acute: High riskDependency: High risk

Images

Quick reference

Routes
Oral
Form
Powder

Duration

Onset
30 Minutes
Total duration
6 Hours

Experience

Primary effects

  • Causes mild to moderate stimulation and euphoria, often described as a mix between amphetamine and MDMA.
  • Induces warmth, contentment, and a blissful state; pupils may be dilated.

Peak character

  • A pleasant plateau of positivity and contentedness with an empathetic edge, without being overwhelming.
  • Stimulation is present but not compulsive or dominant, unlike some amphetamines.
  • Mild to moderate increase in libido, but not overwhelmingly strong or compulsive at typical doses.

Negatives / side effects

  • Some users report difficulty sleeping. Taking benzodiazepines like Etizolam may be necessary to aid sleep.
  • There are alarming reports of 4-FA potentially causing cerebral hemorrhaging, emphasizing the need for dosage restraint.

Aftereffects / comedown

  • Aftereffects can include a feeling of flatness for several days, similar to an MDMA comedown, requiring appropriate aftercare.

Reference dosage

Reference ranges from third-party harm-reduction databases. Individual response varies enormously — start lower than you think.

Any route
threshold10mg+
light25mg+
common50mg+
strong100mg+
heavy150mg+

Reagent testing

Recommended reagents
MarquisMandelinLiebermannRobadope
Expected reactions
MarquisOrange → brown (slow)
MandelinGreen → brown
LiebermannOrange → brown
RobadopeOrange/red

Adulterant detection: 4-fluoroamphetamine. Substitution with plain amphetamine (4-FA is often used as a 'nicer' alternative) — reagents are similar. More rapid/darker Marquis may suggest amphetamine.

Cardiac risk at high doses; substitution with more potent stimulants is dangerous.

Source

Reference fields and narrative for 4-FA extracted from The Drug Users Bible by Dominic Milton Trott (MxZero Publishing, 2022).

drugusersbible.com

Harm reduction notice

This platform provides educational and harm-reduction information adapted from public reference material. It does not endorse, encourage, or facilitate drug use. It is not medical advice. If you or someone near you may be in a medical emergency, contact local emergency services immediately.