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A-PHP Facts

Stimulant; Substituted cathinone; Dopamine reuptake inhibitor

Description

α-PHP (α-pyrrolidinohexanophenone) is a synthetic stimulant of the pyrovalerone cathinone class. It blocks dopamine and norepinephrine reuptake in the brain, flooding reward circuits with dopamine and driving intense euphoria and stimulation.[1][2]

Subjective effects include intense euphoria, focused energy, wakefulness, psychomotor drive, and a compulsive compulsive redosing urge. The experience is a pure stimulant arc — driven and focused, without the warmth or social ease of serotonergic stimulants — most comparable to cocaine but with a far longer tail.

α-PHP has high abuse liability — preclinical models rate its reward-circuit activation as equivalent to cocaine[3] — and causes cardiovascular toxicity including rapid heart rate and muscle breakdown.[4] Its estimated 37-hour half-life means effects and toxicity persist far longer than most stimulants, and psychotic episodes can last days.[5]

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 3 mgLight5 – 10 mgCommon10 – 25 mgStrong25 – 45 mgHeavy45+ mg

Starts in 20 – 45 minLasts 4 – 8 hoursAfter-effects 12 – 48 hours

Body and dependence

Acute toxicity
Moderate
Chronic toxicity
Moderate
Physical dependence
Low
Psychological dependence
High
Withdrawal
Moderate
Compulsive redosing
High

Tolerance

Builds
Rapid
Fully resets after
Not recorded
Carries over to
cocaine; α-PVP; MDPV; amphetamine; methamphetamine

Effectslikely at a common dose

Perception
Dreaming suppression; +8 possible, including Visual haze / noise
Body
Stimulation; Appetite suppression; Restlessness; Vasoconstriction; Wakefulness; Insomnia; Pupil dilation; +20 possible, including Excessive sweating, Heart rate perception changes, Muscle tension
Thinking
Cognitive euphoria; Compulsive redosing urge; Thought acceleration; Cognitive fatigue; +21 possible, including Cognitive dysphoria, Information processing suppression, Cognitive impairment
Feeling
Euphoria; +8 possible, including Anxiety, Depression, Anhedonia
Self
none likely · 9 possible, including Craving, Ego inflation, Compulsive repetitive behavior
Time
none likely · 1 possible

Who shouldn't take it

Absolute
Cardiovascular disease; Psychotic disorders; Bipolar disorder; Pregnancy; MAO inhibitor use
Relative
Epilepsy; Concurrent stimulant use

Combinations62 recorded

Lethal (2)
Ibogaine; Tramadol
Dangerous (29)
Alpha-2 adrenergic receptor antagonist; Amphetamines; Benzodiazepines, Barbiturates; Ephedrine, Pseudoephedrine; Local anesthetics; MAOIs; MDMA, Amphetamines; MDMA, MDA; NDRIs (Wellbutrin); NRIs; Opioids; SSRIs; Stimulants; Anticholinergics; Antipsychotics; Buspirone; Caffeine; Dopamine agonists; DXM; GHB, Baclofen; GHB, GBL; Ketamine, DXM, PCP; Lithium; NSAIDs; and 5 more, see full page
Caution (28)
See full page: psychedex.org/substances/a-php
Not graded (3)
Not listed never means safe.

Seek help immediately if

  • Chest pain; racing, pounding, or irregular heartbeat
  • Very high body temperature; heavy sweating; hot, flushed skin
  • Severe agitation, paranoia, panic, or confusion
  • Severe headache; muscle rigidity or twitching
  • Seizures
  • Signs of stroke — face drooping, one-sided weakness, slurred speech
  • Difficulty breathing; collapse or unconsciousness

What to do

  1. Call emergency services for chest pain, overheating, seizure, or unresponsiveness
  2. Move them to a cool, quiet place and reduce stimulation
  3. Cool the body — remove excess clothing, apply cool damp cloths, fan them
  4. Keep them calm; reassure — panic worsens the cardiovascular strain
  5. If seizing, protect from injury (don't restrain); recovery position afterward
  6. Monitor breathing and be ready to give rescue breaths / CPR

Most stimulant overdoses settle with cooling, a calm environment, and time. The medical danger is hyperthermia, cardiac events (arrhythmia, heart attack, stroke), and seizures — get help immediately if any appear.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Kolaczynska 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
  2. [2]
    ^Simmler LD, Buser TA, Donzelli M, et al. (2012) Pharmacological characterization of designer cathinones in vitro — British Journal of Pharmacology doi:10.1111/j.1476-5381.2012.02145.x
  3. [3]
    ^Baird TR, Davies RA, Glennon RA, Peace MR, Negus SS (2021) A Strategy to Prioritize Emerging Drugs of Abuse for Analysis: Abuse Liability Testing Using Intracranial Self-Stimulation (ICSS) in Rats and Validation with α-Pyrrolidinohexanophenone (α-PHP) — Emerging Trends in Drugs, Addictions, and Health doi:10.1016/j.etdah.2021.100004
  4. [4]
    ^Bassi M, Roda E, Tirri M, Corli G, Bilel S, et al. (2025) α-PHP: Acute effects and pharmacokinetic in male and female mice, and clinical data on related intoxications — Drug and Alcohol Dependence doi:10.1016/j.drugalcdep.2025.112596
  5. [5]
    ^Fujita Y, Mita T, Usui K, Kamijo Y, Kikuchi S, Onodera M, Fujino Y, Inoue Y (2018) Toxicokinetics of the Synthetic Cathinone α-Pyrrolidinohexanophenone — Journal of Analytical Toxicology doi:10.1093/jat/bkx080
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