Short intro: Iยm very experienced with drugs, although this drug is the first one Iยve done in quite a while (excluding my daily bupropion and buspirone regimen). Tons of stimulant experience so I had a rough idea of what to expect with this particular substance.
4F-PHP
Encyclopedic
Encyclopedic
Typical encyclopedia coverage. Cross-reference for important decisions.
- 3 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 18 combo interactions documented
- classified Tentative
- classified Research-chemical
Encyclopedic
Typical encyclopedia coverage. Cross-reference for important decisions.
- 3 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 18 combo interactions documented
- classified Tentative
- classified Research-chemical
Aliases: 4-fluoro-alpha-php, 4-fluoro-pyrrolidinohexanophenone
Summary
4F-PHP is a potent synthetic stimulant in the pyrrolidinophenone/cathinone class, structurally related to alpha-PHP with a fluorine substitution at the 4-position of the phenyl ring. First identified in 2017, it produces strong stimulation and euphoria with high compulsivity. User reports suggest it is slightly less prone to extreme side effects than alpha-PVP but still carries significant risks including cardiovascular strain, anxiety, paranoia, and stimulant psychosis.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Insufflated | 5-15mg | 15-30mg | 30-50mg | 50mg+ |
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 10-30 min | 20-40 min | 1-3 hrs | 2-4 hrs | 3-6 hrs |
| Insufflated | 2-10 min | 10-20 min | 1-2 hrs | 1-3 hrs | 3-6 hrs |
| Vaporized | 1-5 min | 5-10 min | 15-45 min | 30-90 min | 3-6 hrs |
Effect Profile
1 reportsScores (1–10) curated from multiple sources:
- Effect keyword matching from PsychonautWiki catalog
- Weighted by importance: core (×3), major (×2), minor (×1)
Stimulant
5.4
Moderate+
5/10
Strong euphoria and anxiety/jitters with moderate focus, low stimulation
Stimulation / Energy
×3
3
stimulation
Euphoria / Mood Lift
×2
10
physical euphoria
euphoria
cognitive euphoria
motivation enhancement
Focus / Productivity
×2
7
focus enhancement
thought acceleration
motivation enhancement
Anxiety / Jitters
×1
10
anxiety
paranoia
increased heart rate
teeth grinding
vasoconstriction
sweating
Based on reports from:
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The PsychonautWiki Journal logging app doesn't include every substance. To track 4F-PHP there, start adding an ingestion, search for the name, and choose to add it as a custom substance. Paste these values:
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Import this file as custom substances
and you get "4F-PHP (Substance Search)" with every
route's full dose ladder and timeline, no typing. Works on iOS and
Android (v15+); the format is confirmed by the app's
developer. The manual values below work for older
versions.
Name
4F-PHP
Unit
mg
Description
4F-PHP Source: SubstanceSearch (substancesearch.com) Oral dose (mg): threshold <5 Insufflated dose (mg): light 5-15 ยท common 15-30 ยท strong 30-50 ยท heavy 50+ Vaporized dose (mg): threshold <2 Oral duration: onset 10-30m ยท come-up 20-40m ยท peak 1-3h ยท offset 2-4h ยท total 3-6h ยท after-effects 4-24h Insufflated duration: onset 2-10m ยท come-up 10-20m ยท peak 1-2h ยท offset 1-3h ยท total 3-6h ยท after-effects 4-24h Vaporized duration: onset 1-5m ยท come-up 5-10m ยท peak 15-45m ยท offset 0.5-1.5h ยท total 3-6h ยท after-effects 2-12h Note: ranges are harm-reduction guidance, not a prescription. Start low, go slow, and test your substances.
Tip: for quicker logging you can also add a Custom Unit in the app, e.g. common dose ~ 22.5 mg (Insufflated).
The app keeps custom substances simple, so the full dose ranges live in the description text above. Ranges are harm-reduction guidance, not a prescription.
Tolerance
Build-up
develops over days to weeks of regular use
Reset
3โ7 days for acute; 1โ3 weeks for full reset
Tolerance Decay
Full tolerance
2d
Half tolerance
3d
Baseline
~21d
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.
Tolerance develops rapidly with repeated doses/binges and partially subsides over several days; full return to baseline typically requires 1โ2+ weeks after heavy use. Data are largely anecdotal from user communities and extrapolated from related pyrrolidinophenones.
Cross-Tolerances
Effects
Positive
- Stimulation
- Physical euphoria
Negative
- Increased heart rate
- Increased perspiration
- Teeth grinding
- Insomnia
- Vasoconstriction
- Increased blood pressure
- Sweating
- Temperature regulation suppression
Positive
- Euphoria
- Cognitive euphoria
- Focus enhancement
- Motivation enhancement
Negative
- Compulsive redosing
- Anxiety
- Paranoia
- Ego inflation
- Thought acceleration
- Time distortion
Positive
- Increased libido
- Tactile enhancement
- Increased music appreciation
Negative
- Disinhibition
- Appetite suppression
- Light sensitivity
- Dehydration
- Vibrating vision
- Increase sexuality
Combinations
Cross-Check 4F-PHP 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. Tags summarise each author's own verdict — how reports are classified.
Erowid 1 report 1 neutral visit
4F-PHP's nerd page
Pharmacology, chemical data, effect profiles, and more
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Helpful Links
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