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    Disclaimer
    โ˜  This is an extremely potent opioid active in microgram doses. Accidental overdose can be rapidly fatal. Naloxone should always be on hand.
    ๐Ÿงช This is a research chemical with limited data on its long-term health effects, toxicity profile, and safe dosage ranges.

    Cyclopentyl-Fentanyl Limited data
    Limited data
    Sparse data. Doses and effects may be unreliable or untested.
    • 1 source
    • no dose data
    • 19 combo interactions documented
    • classified Tentative
    • classified Research-chemical

    Aliases: Cp-f, cpf

    Summary TripSit

    Cyclopentylfentanyl is a fentanyl analogue and a full ฮผ-opioid agonist, with published receptor pharmacology (EC50 around 13 nM, ~92% efficacy). It has been identified in fatal overdose casework. No human dose is established, and it should be assumed to carry fentanyl-scale lethality โ€” active in micrograms, with respiratory depression as the mechanism of death. Naloxone works but repeat doses are commonly required.

    Effect Profile

    class estimate

    Scores (1–10) curated from multiple sources:

    • Effect keyword matching from PsychonautWiki catalog
    • No reports exist for this substance. Its effect list is the one shared by 2 other substances of the same class, so the scores below describe the class, not this compound.
    • 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

    Tolerance

    Build-up develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
    Reset 7โ€“14 days for partial reset; full reset may take weeks โ€” 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
    • 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
    • Brightened colour
    • Tactile enhancement
    Negative
    • Light sensitivity
    • Disinhibition
    • Appetite suppression
    • Dehydration
    Neutral
    • Dulled perception
    • Drifting

    Combinations TripSit

    Cross-Check Cyclopentyl-Fentanyl with another substance

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