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    Disclaimer
    ☠ This is a fentanyl analogue active in microgram doses. Accidental overdose can be rapidly fatal. Naloxone should always be on hand.

    Parafluorofentanyl

    Aliases: Pff, 4-fluorofentanyl

    Depressant Opioid

    Summary TripSit

    Rare, little known and extremely potent analogue of Fentanyl developed by Janssen Pharmaceutica in the 1960s. Use with extreme caution and never mix with other depressants.

    Dose Information TripSit

    ROA Light Common Strong Heavy
    Insufflated 10-25ug 25-40ug 40-65ug 65ug+
    Light Common Strong Heavy

    Onset, Duration & After-effects TripSit

    ROA Onset Peak After Effects
    Insufflated 0-1 min 2-3 hrs 1-2 hrs

    Effect Profile

    Scores (1–10) curated from multiple sources:

    • Effect keyword matching from PsychonautWiki catalog
    • Weighted by importance: core (×3), major (×2), minor (×1)

    Full methodology

    Opioid 3.9
    Moderate 4/10

    Moderate euphoria with mild itching/nausea, low sedation

    Euphoria / Warmth ×3
    6
    euphoria cognitive euphoria
    Analgesia ×2
    0
    Sedation / Relaxation ×1
    3
    sedation
    ⚠ Itching / Nausea ×1
    4
    nausea
    Based on reports from:
    Erowid Experience Reports PsychonautWiki Parafluorofentanyl
    View methodology →

    Tolerance

    Build-up develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
    Reset 7–14 days for partial reset; full reset may take weeks — tolerance loss greatly increases overdose risk

    Tolerance Decay

    Full tolerance 1d Half tolerance 21d Baseline ~35d

    Effects

    Positive
    • Stimulation
    Negative
    • Motor impairment
    • Increased heart rate
    • Pupil dilation
    • Insomnia
    • Nausea
    • Vasoconstriction
    • Restlessness
    Neutral
    • Sedation
    • Decreased appetite
    Positive
    • Reduced anxiety
    • Euphoria
    • Cognitive euphoria
    • Wakefulness
    • Empathy
    Negative
    • Anxiety
    • Confusion
    • Compulsive redosing
    Neutral
    • Time distortion
    • Talkativeness
    Positive
    • Increased music appreciation
    • Color enhancement
    • Tactile enhancement
    • Brightened colour
    Negative
    • Light sensitivity
    • Appetite suppression
    • Dehydration
    • Disinhibition
    Neutral
    • Dulled perception
    • Drifting

    Combinations TripSit

    Parafluorofentanyl's nerd page Pharmacology, chemical data, effect profiles, and more
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    Helpful Links

    💊 Pill Identifier 📘 Experience Reports 📖 TripSit 📖 PsychonautWiki