This is an extreme tale of caution, as I almost extinguished my flame, my light, my life - 4 times within 2 weeks with this material . To give context, I have quite a extensive history with most classes of compounds. I've worked with many phenethylamines and tryptamines, as well as several stimulants and opiates.
Furanylfentanyl
Encyclopedic
Encyclopedic
Typical encyclopedia coverage. Cross-reference for important decisions.
- 3 corroborating sources
- 2 ROAs with full dose ladders
- duration data present
- 19 combo interactions documented
- classified Tentative
- classified Research-chemical
Encyclopedic
Typical encyclopedia coverage. Cross-reference for important decisions.
- 3 corroborating sources
- 2 ROAs with full dose ladders
- duration data present
- 19 combo interactions documented
- classified Tentative
- classified Research-chemical
Aliases: Fu-f, furanyl-fentanyl
Summary
Furanylfentanyl (Fu-F) is a potent ฮผ-opioid full agonist approximately 50-100 times more potent than morphine and roughly half as potent as fentanyl. U.S. and EU regulators placed it in Schedule I after at least 23 confirmed deaths in Europe alone by 2017. It exhibits rapid-onset but short-lived euphoria and profound respiratory depression.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Insufflated | 200-400ug | 400-800ug | 800-1600ug | 1600ug+ |
| Oral | 300-500ug | 500-900ug | 900-1600ยตg | 1600ยตg+ |
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Peak | Offset | Total |
|---|---|---|---|---|
| Insufflated | 1-5 min | 15-30 min | 1-2 hrs | 1-3 hrs |
| Oral | 1-10 min | 1-3 hrs | - | 1-3 hrs |
Effect Profile
3 reportsScores (1–10) curated from multiple sources:
- Effect keyword matching from PsychonautWiki catalog
- Weighted by importance: core (×3), major (×2), minor (×1)
Opioid
7.0
Strong+
7/10
Strong euphoria, itching/nausea, and pain relief with low sedation
Euphoria / Warmth
×3
10
physical euphoria
cognitive euphoria
euphoria
warmth
mood lift
Analgesia
×2
8
analgesia
pain relief
Sedation / Relaxation
×1
3
sedation
Itching / Nausea
×1
10
itching
nausea
constipation
Based on reports from:
Tolerance
Build-up
develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
Reset
7โ14 days for partial reset; full reset may take weeks โ tolerance loss greatly increases overdose risk
Tolerance Decay
Full tolerance
7d
Half tolerance
7d
Baseline
~35d
Acute tolerance: develops within a single session โ the reset numbers above apply after sustained heavy use, not after one binge. Within-session tachyphylaxis usually resets largely overnight.
Opioid tolerance accrues rapidly with repeated use and decays over days to weeks; resuming prior doses after a break markedly increases overdose risk. Data specific to furanylfentanyl are limited; estimates are based on general opioid tolerance patterns and case observations.
Cross-Tolerances
opioids
60%
Effects
Aggregated from 3 Erowid experience reports
Positive Effects 1
Anxiety Suppression
100.0%
70%
Adverse Effects 0
Combinations
Cross-Check Furanylfentanyl with another substanceCommunity Trip Reports
Anecdotal first-person accounts from Reddit, Erowid, and Bluelight. Click a source to expand. Reports are harm-reduction context, not medical guidance.
Erowid 3 reports 3 cautionary visit
Vaporised Fentanyl Overdose Hey folks, let me tell you the story of how I flipped my life upside down. Back in November I got out of a very toxic and abusive relationship and spiralled into a 4 month bender, abusing anything and everything I could get my hands on, which ended in a near fatal overdose.
Vaporised Fentanyl Overdose Let me tell you the story of how I flipped my life upside down. Back in November I got out of a very toxic and abusive relationship and spiralled into a 4 month bender, abusing anything and everything I could get my hands on, which ended in a near fatal overdose.
Furanylfentanyl's nerd page
Pharmacology, chemical data, effect profiles, and more
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