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α-PHP (α-pyrrolidinohexanophenone) — also known as PV-7 — is a synthetic stimulant of the pyrovalerone cathinone class. It is the direct one-carbon extension of α-PVP, with nearly identical potency. It blocks dopamine and norepinephrine recycling in the brain,[1] flooding the reward circuit and producing intense stimulation.[2]

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Threshold
< 2 mg
Light
4 – 10 mg
Common
10 – 20 mg
Strong
20 – 35 mg
Heavy
35+ mg
12340 h2 h4 h5 h
1Onset
5m–15m2Come-up
5m–15m3Peak
2h–4h4Resolution
1h–2hAftereffects4h–10h
Total6h–14h
Buildupmoderate
Full reset14 days
Cross-tol.
cocaine, methylphenidate, α-PVP +3 more
Absolute4 entries
Severe cardiovascular diseasePregnancyBreastfeedingConcurrent MAOI use
Relative5 entries
Seizure disordersPsychotic disordersBipolar disorderHepatic impairmentRenal impairment
Dosage varies by body weight, tolerance & metabolism · Not medical advice · Terms

Patented in 1967 as part of a series of synthetic stimulants, α-PHP was never developed as a medicine and remained obscure for nearly five decades.[3] It appeared on illicit markets in Japan in 2014, filling the gap left when regulators moved against α-PVP.[3] It is now internationally controlled — US Schedule I since June 2022[4] and UN Schedule II since December 2020.

Subjective effects include intense euphoria, high physical energy, wakefulness, heightened focus, and a powerful compulsive redosing urge. The experience is overwhelmingly stimulant — a sharp dopaminergic rush with no empathogenic warmth or perceptual distortion. Paranoia, auditory and visual hallucinations, and agitated dysphoria emerge reliably with extended use or high cumulative doses.

α-PHP carries high abuse liability — animal data rank its addictive potential comparable to methamphetamine[5] — with acute toxicity including dangerous elevations in heart rate, blood pressure, and body temperature. Its slow release from the DAT[6] sustains compulsive redosing long after the peak has passed, compounding cardiovascular and psychiatric risk.[7] No controlled human studies exist; the evidence rests on animal pharmacology, forensic case series, and structural analogy with α-PVP.

History[edit]

Discovery

α-PHP was first described in a US patent issued in 1967,[3] part of a series of synthetic stimulants explored as potential medicines. None reached clinical trials. The patent expired in 1984, leaving the synthesis freely available.

Emergence as a novel psychoactive substance

α-PHP appeared on illicit markets in Japan in 2014,[3] entering circulation after regulators moved against its structural predecessor α-PVP.[8] A one-carbon change to the side chain was enough to temporarily sidestep scheduling controls.[1] This evasion strategy — minimal structural change, preserved pharmacological core — is the defining pattern of second-generation synthetic cathinone markets.

Scheduling and research

The WHO reviewed α-PHP in December 2019[9] and recommended UN Schedule II placement, adopted in December 2020.[3] The US DEA permanently placed it in Schedule I in June 2022.[4] No clinical trials have been registered.

Chemistry[edit]

Structural class

α-PHP is a synthetic cathinone of the pyrovalerone subclass — a family built on a phenyl ring bearing a carbonyl group and a pyrrolidine nitrogen ring. It is the direct one-carbon extension of α-PVP, and this chain elongation increases potency at the DAT,[1] enhancing both dopamine and NET inhibition within the pyrovalerone series.[2]

Molecular properties

The molecular formula is C₁₆H₂₃NO (molecular weight 245.36 g/mol).[3] α-PHP has a single chirality center, producing two mirror-image forms. The S-enantiomer of closely related pyrovalerone compounds dissociates more slowly from the dopamine transporter[6] — a property presumed to apply to α-PHP on structural grounds but not yet directly confirmed.

Pharmacology[edit]

Mechanism of action

α-PHP blocks the proteins that recycle dopamine and norepinephrine back into nerve cells. This floods the spaces between neurons with both chemicals, amplifying reward signaling and physical arousal. It does not force neurotransmitter release the way amphetamines do — it is strictly a reuptake blocker, placing it in the same mechanistic category as cocaine and methylphenidate.[2]

α-PHP strongly favors dopamine over serotonin[1] and has almost no effect on serotonin signaling,[2] which explains the absence of empathogenic or psychedelic qualities. The active form of the molecule clings to the DAT longer than cocaine does,[6] directly predicting longer-lasting and more compulsive stimulant effects.

Pharmacokinetics

No controlled pharmacokinetic study has been conducted in humans. Review literature cites an approximate half-life of 37 hours and elimination over roughly 150 hours,[3] though these figures likely come from community estimates rather than controlled research. safety citation needed Extensive liver metabolism has been documented — 19 Phase I and 9 Phase II metabolites identified across published studies.[3][7]

Neuroscience[edit]

Where it acts

α-PHP's primary target is the brain's core reward circuit — the pathway running to the nucleus accumbens. Blocking dopamine recycling here floods the region with dopamine, powerfully activating the neurons that encode motivation and reward. Concurrent norepinephrine blockade drives the arousal, alertness, and cardiovascular acceleration that accompany the stimulant experience.

The S-enantiomer of pyrovalerone compounds clings to the DAT longer than cocaine does.[6] This means dopamine stays elevated in the reward circuit longer than equilibrium binding alone would predict — providing a neurochemical basis for the intense and prolonged reward signaling associated with α-PHP.

Why it matters

Sustained dopamine flooding amplifies the brain's wanting system — the compulsive drive to seek another dose — more than it amplifies actual pleasure.[10] Animal studies confirm this: α-PHP facilitates brain reward at a magnitude equivalent to α-PVP and comparable to methamphetamine.[5][11] The result is compulsive redosing even as the subjective high fades.

Subjective Effects[edit]

Summary

α-PHP is an almost purely dopaminergic experience. There is no warmth, no empathogenic connection, no perceptual distortion at typical doses. What it delivers is sharp: energy, wakefulness, and a powerful sense of reward that peaks quickly and fades in a way that makes redosing feel necessary. Extended sessions reliably turn toward paranoia and agitation.

Relative to α-PVP, the experience is nearly identical — animal data confirm equivalent reward potency.[5] Compared to cocaine, α-PHP lasts longer per dose due to slower DAT release,[6] and lacks cocaine's mild serotonergic quality. The result is a narrower, starker stimulant profile.

Effect Grid

Dose Level:
Description

Pronounced euphoria and strong stimulation dominate the experience. Cognitive euphoria is vivid, thought acceleration is marked, and wakefulness is sustained. The compulsive redosing urge becomes a prominent feature — the slow dissociation of α-PHP from the dopamine transporter sustains incentive motivation even as peak euphoria begins to plateau.

Heart rate and blood pressure are clearly elevated. Appetite suppression is strong, excessive sweating is common, and restlessness may become difficult to manage. Temperature dysregulation and trembling may appear.

Insomnia is virtually guaranteed for many hours after dosing. Extended sessions at this tier reliably escalate toward anxiety and paranoid ideation. Functional impairment is significant.

Modeled from the effect's dose-dependence curve — not per-substance measurements.

Perception(6)likelihood · intensity
Dreaming suppression
likely
Touch enhancement
possible
Auditory hallucinations
v.rare
External hallucinations
v.rare
Internal hallucinations
v.rare
Shadow people
v.rare

Shadow people

Body(26)likelihood · intensity
Stimulation
likely
Wakefulness
likely
Appetite suppression
likely
Insomnia
likely
Pupil dilation
likely
Vasoconstriction!
likely
Body high
likely
Dry mouth
likely
Motor control impairment!
possible

Insomnia · Pupil dilation · Body high · Dry mouth · Heart rate perception changes · Restlessness · Dehydration sensation · Excessive sweating · Muscle tension · Respiratory stimulation · Tactile euphoria · Bruxism · Spontaneous body sensations · Tingling / electric sensations · Vibrations / buzzing · Headache · Nausea · Sexual arousal enhancement · Trembling · Dizziness · Involuntary body movements

Heart rate perception changes · Restlessness · Dehydration sensation · Excessive sweating · Muscle tension · Respiratory stimulation · Tactile euphoria · Bruxism · Spontaneous body sensations · Tingling / electric sensations · Vibrations / buzzing · Headache · Nausea · Sexual arousal enhancement · Trembling · Dizziness · Involuntary body movements

Thinking(14)likelihood · intensity
Cognitive euphoria
likely
Compulsive redosing urge!
likely
Thought acceleration
likely
Motivation enhancement
possible
Multiple thought streams
possible
Thought loops
possible
Cognitive dysphoria
possible
Delirium!
v.rare
Delusions!
v.rare

Multiple thought streams · Thought loops · Cognitive dysphoria · Focus enhancement · Information processing enhancement · Cognitive impairment · Confusion · Thought disorganization · Delusions

Focus enhancement · Information processing enhancement · Cognitive impairment · Confusion · Thought disorganization

Feeling(6)likelihood · intensity
Euphoria
likely
Anxiety
possible
Irritability
possible
Dysphoria
possible
Paranoia!
possible
Mania!
rare

Dysphoria

Self(10)likelihood · intensity
Craving
possible
Compulsive repetitive behavior!
possible
Disinhibition
possible
Communication enhancement
possible
Sociability enhancement
possible
Social connection
possible
Flow state
possible
Ego inflation
possible
Self-control suppression!
rare

Sociability enhancement · Social connection · Flow state · Ego inflation · Derealization

Derealization

Time(1)likelihood · intensity
Time alteration
possible
Awareness(1)likelihood · intensity
Reality testing impairment!
v.rare
Likelihood: how common this effect is at the selected dose level.This effect has safety implications — review before use.

Timeline

Safety[edit]

Harm
Acute toxicity
High
Chronic toxicity
Moderate
Withdrawal
Moderate
Tolerance buildup
moderate
Tolerance reset
14 days
Dependence
Physical
Low
Psychological
High
Compulsive redosing
High
Dose escalation
Moderate
Cross-tol.
cocaine · methylphenidate · α-PVP
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

No lethal dose has been established for α-PHP in any species, and all human toxicity data come from forensic and clinical cases, nearly all involving multiple substances simultaneously.

Acute toxicity

Acute toxicity follows the pattern of powerful stimulants: agitation, tremors, rapid heart rate, high blood pressure, dangerously elevated body temperature, and — in severe cases — muscle breakdown.[12] Blood concentrations in forensic cases ranged from 1–83 ng/mL, but near-universal polydrug use prevents isolating α-PHP's specific contribution.[7]

Hyperthermia

Dangerous overheating is a serious acute risk across stimulant cathinones.[13] Stimulant activity generates heat directly; agitation-driven muscular activity adds to it. Hot environments, physical exertion, or combining with other stimulants can push body temperature to life-threatening levels rapidly.

Reproductive toxicity

A case report documented fetal death following maternal use of both α-PHP and MDPHP.[14] Polydrug context prevents definitive attribution, but the case constitutes a serious reproductive safety signal. Two additional cases of neonatal α-PHP exposure were confirmed via meconium analysis.[7] safety citation needed

Genotoxicity

α-PHP itself was not directly mutagenic in laboratory cell-line testing.[15] When processed through simulated liver metabolism, its metabolites showed mutagenic potential — cell toxicity was observed at concentrations of 35–100 µM. The genotoxic risk appears to come from metabolites rather than the parent compound, relevant to chronic exposure scenarios.

Neurotoxicity

Synthetic cathinones as a class can produce brain swelling, seizures, reduced seizure threshold, and excited delirium.[13] α-PHP's minimal serotonin activity reduces its serotonin syndrome risk relative to serotonergic cathinones, but the dopaminergic toxicity profile — including seizure risk and excited delirium — applies on mechanistic grounds. inferred No direct neurotoxicity studies have been published for α-PHP.

Psychological risks

No controlled studies have characterized α-PHP's psychological risk profile.

Agitation and aggression are documented in forensic and clinical cases.[7][12] Both visual and auditory hallucinations, paranoid thinking, and disorientation appear with high doses or prolonged use — consistent with excessive dopamine stimulation.[7][12]

Excited delirium — extreme agitation, altered consciousness, dangerous overheating, and risk of sudden death — represents the severe end of the spectrum. It is documented across the cathinone class[13] and is particularly associated with high-dose or prolonged binges. inferred

Compulsive redosing is driven by slow DAT dissociation,[6][10] which sustains the brain's wanting circuitry long after the peak fades, increasing cumulative exposure and with it cardiovascular, hyperthermic, and psychiatric risk. In forensic cases, 60% involved opioid co-use and 35% benzodiazepines[7] — likely reflecting concurrent dependence across substance classes.

Systematic reviews of synthetic cathinones find anxiety, depression, and psychotic symptoms persisting beyond acute intoxication in some cases.[16] Whether α-PHP specifically produces lasting psychiatric consequences has not been studied.

Tolerance and dependence

No controlled tolerance or dependence studies have been published for α-PHP. Animal brain-reward data place its addictive potential equivalent to α-PVP and comparable to methamphetamine.[5][11] The slow dopamine transporter dissociation of the pyrovalerone class[6] may produce more sustained reward than cocaine, potentially elevating addiction risk beyond what potency comparisons suggest.

Acute tolerance to euphoria with preserved cardiovascular stimulation is expected with repeated dosing, based on other dopamine-blocking stimulants. Cross-tolerance with cocaine, methylphenidate, and other pyrovalerone cathinones is expected from the shared mechanism. No substance-specific data exist for either. inferred

No clinical withdrawal characterization exists. By analogy with cocaine and methamphetamine, cessation after heavy use is expected to bring dysphoria, anhedonia, fatigue, and hypersomnia.[13] inferred Cessation is not physically dangerous — unlike alcohol or benzodiazepines — but the psychological withdrawal benefits from structured support.

Drug interactions

No published drug interaction studies exist for α-PHP. The following interactions are inferred from its mechanism and class-level evidence.

Combining with MAOIs (phenelzine, tranylcypromine, moclobemide) blocks monoamine breakdown while simultaneously blocking dopamine and norepinephrine recycling — the combination can produce a dangerous, potentially fatal catecholamine overload.[13] safety citation needed

Other stimulants — cocaine, amphetamines, or other cathinones — add to the cardiovascular and nervous system burden. Cocaine co-use was found in 20% of forensic cases.[7]

The most common forensic polydrug pattern was opioid co-use (60% of cases).[7] Opioid-driven respiratory depression can be masked by stimulant arousal, and the stimulant's cardiovascular effects compound hemodynamic instability — a combination with overlapping, dual dangers.

α-PHP has minimal SERT activity,[1] but serotonin syndrome has been reported across the cathinone class.[13] Caution is warranted with SSRIs, SNRIs, triptans, tramadol, and linezolid. safety citation needed

Lithium may lower seizure threshold. Combined with a stimulant that independently reduces seizure threshold,[13] this could produce additive risk. No direct data. safety citation needed

Contraindications

No substance-specific contraindication data have been published. The following are inferred from α-PHP's mechanism and class-level evidence.

Absolute contraindications:

  • Concurrent MAOI use: Risk of fatal hypertensive crisis.[13] safety citation needed
  • Pregnancy: Fetal death associated with α-PHP exposure (polydrug context);[14] neonatal exposure confirmed via meconium.[7] Stimulant activity poses inherent risk to fetal blood flow.
  • Severe heart conditions: Uncontrolled high blood pressure, coronary artery disease, heart failure, and irregular heart rhythm are absolute contraindications given documented rapid heart rate, high blood pressure, and chest pain in clinical cases.[12] inferred

Relative contraindications:

  • Seizure disorders: Synthetic cathinones reduce seizure threshold.[13] inferred
  • Psychiatric conditions: Documented hallucinations, paranoia, and delirium[7] suggest that pre-existing psychotic disorders, bipolar disorder, and severe anxiety disorders increase risk.
  • Liver impairment: α-PHP undergoes extensive liver metabolism.[3] Impaired liver function could alter metabolite profiles unpredictably. inferred
  • Kidney impairment: Impaired kidney function may prolong metabolite exposure. inferred

Harm Reduction[edit]

Forms & Identification

Reagent ResultsNot recorded+ add reagent results
AppearanceNot recorded+ add appearance
Red FlagsNot recorded+ add red flags

Reagent testing is important because pyrovalerone cathinones are visually indistinguishable from one another and from many unrelated substances sold as white or off-white powders. The free base and hydrochloride salt forms differ in appearance and vaporization behavior — relevant to both testing and dosing decisions.

Because α-PHP has never been pharmaceutical-grade, purity varies dramatically between batches. Even material from the same source can differ in potency. Accurate dosing is impossible without confirming substance identity and estimating purity first.

Guidelines

  • Test every batch with reagent kits before use. Confirm substance identity and check for common adulterants.
  • Pre-measure all doses before a session begins. Set a maximum total dose and a hard stop time.
  • Have a sober, trusted person present — particularly with inhalation or intravenous routes, which carry the highest compulsive redosing risk.
  • Stay hydrated with small, regular sips of water or electrolyte solution. Do not overhydrate.
  • Monitor body temperature. If skin feels hot to the touch, move to a cool environment, remove excess clothing, and apply cool water.
  • Do not use in enclosed, overheated spaces. Ambient heat compounds stimulant-driven hyperthermia.
  • Avoid redosing when euphoria fades — this is the pharmacological profile working as expected, not a signal that more is needed.
  • Eat a meal before use. Stimulants suppress appetite, and caloric depletion worsens comedown severity.

Set & Setting

α-PHP's pharmacological profile creates a powerful compulsive redosing urge that intensifies as a session continues. Using alone removes the external check another person provides against escalation. Enclosed, hot environments compound hyperthermia risk.

Physical exhaustion, sleep deprivation, and pre-existing anxiety all lower the threshold for the agitated, paranoid states that emerge with escalating cumulative dose. Setting a firm endpoint before beginning — and having a trusted person present to enforce it — materially reduces the probability of a session escalating into a binge.

Aftercare & integration. The comedown from α-PHP follows the standard stimulant pattern: as dopamine levels normalize, dysphoria, fatigue, irritability, and strong sleep drive set in. This is expected, not dangerous — but the temptation to redose to avoid the comedown is the single most common pathway into extended binges.

Sleep is the highest priority. Stimulant use disrupts sleep architecture; allow extended rest without alarm clocks. Darkness and quiet accelerate recovery.

Nutrition follows sleep. Eat calorie-dense, easy-to-digest food as soon as appetite returns. Stimulant-driven appetite suppression means the body is often in caloric deficit.

Hydration — continue regular fluid intake through the comedown period. Electrolyte replacement is useful after extended sessions.

Avoid making significant decisions during the 24–48 hours following use. Cognitive and emotional baseline takes time to restore. If low mood, anhedonia, or anxiety persist beyond 72 hours, consider consulting a healthcare provider.

Recovery & Support

α-PHP's pharmacological profile — potent dopamine reward activation with slow transporter dissociation — produces a compulsive use pattern that can escalate quickly from occasional use to regular bingeing. Recognizing the pattern early is critical: increasing session frequency, rising cumulative dose per session, and difficulty stopping mid-session are warning signs.

Professional support options include addiction medicine physicians, cognitive behavioral therapy (CBT) programs — which have the strongest evidence base for stimulant use disorders — and peer support groups such as SMART Recovery or Narcotics Anonymous. No medication is specifically approved for pyrovalerone cathinone dependence, but treatment approaches developed for cocaine and methamphetamine use disorders are considered applicable.

If compulsive use has developed, abrupt cessation is not physically dangerous (unlike alcohol or benzodiazepine withdrawal), but the psychological withdrawal — dysphoria, anhedonia, fatigue, and strong cravings — benefits from structured support.

Recovery resources, crisis lines, and support pathways → View all

Emergency Response

Recognizing an emergency

The following signs indicate a medical emergency, not just discomfort:

Immediate steps

  • 1. Call emergency services immediately if any of the above signs are present.
  • 2. Move the person to a cool, quiet environment. Remove excess clothing.
  • 3. If unconscious but breathing, place in the recovery position (on their side, airway clear).
  • 4. Apply cool (not ice-cold) water to the neck, armpits, and groin to reduce body temperature.
  • 5. Do NOT restrain a severely agitated person unless they are in immediate danger of harming themselves or others — restraint can worsen hyperthermia.
  • 6. Do NOT induce vomiting.
  • 7. Stay with the person until help arrives. Monitor breathing and consciousness.

What to tell the dispatcher

State the substance name (α-PHP or "a synthetic cathinone stimulant"), the approximate amount used, the time of last dose, the route of administration, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during a drug emergency.

references

  1. [1] 
    ^abcdeDavies RA, Nguyen VT, Eltit JM, Glennon RA (2023) Structure-Activity Relationships for a Recently Controlled Synthetic Cathinone Dopamine Transporter Reuptake Inhibitor: α-Pyrrolidinohexiophenone (α-PHP) — ACS Chemical Neuroscience doi:10.1021/acschemneuro.3c00156
  2. [2] 
    ^abcdKolaczynska KE, Thomann J, Hoener MC, Liechti ME (2021) The Pharmacological Profile of Second Generation Pyrovalerone Cathinones and Related Cathinone Derivative. — International journal of molecular sciences doi:10.3390/ijms22158277
  3. [3] 
    ^abcdefghijklmnopqDinis P, Franco J, Margalho C (2024) α-Pyrrolidinohexanophenone (α-PHP) and α-Pyrrolidinoisohexanophenone (α-PiHP): A Review — Life doi:10.3390/life14040429
  4. [4] 
    ^abcDrug Enforcement Administration, US DOJ (2022) Schedules of Controlled Substances: Placement of N-Ethylhexedrone, alpha-Pyrrolidinohexanophenone [et al.] in Schedule I — Federal Register Link
  5. [5] 
    ^abcdTaffe MA, Nguyen JD, Vandewater SA, Grant Y, Dickerson TJ (2021) Effects of α-pyrrolidino-phenone cathinone stimulants on locomotor behavior in female rats. — Drug and Alcohol Dependence doi:10.1016/j.drugalcdep.2021.108910
  6. [6] 
    ^abcdefghNiello M, Sideromenos S, Gradisch R, O'Shea R, et al. (2023) Persistent binding at dopamine transporters determines sustained psychostimulant effects — Proceedings of the National Academy of Sciences doi:10.1073/pnas.2114204120