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:
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
- Appetite Suppression
- 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.
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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