alpha-PiHP
alpha-PiHP (alpha-pyrrolidinoisohexanophenone) is a synthetic cathinone of the pyrrolidinophenone family, a positional isomer of alpha-PHP marketed as a designer stimulant after older pyrovalerones were scheduled. It acts as a norepinephrine-dopamine reuptake inhibitor. Human pharmacology is essentially uncharacterised; nearly all information is anecdotal or derived from forensic casework and analogy to alpha-PVP.
01 Overview
alpha-PiHP emerged on European and Asian research-chemical markets in the late 2010s as a replacement for banned pyrrolidinophenones such as alpha-PVP and alpha-PHP. It is typically sold as a crystalline solid or powder and used insufflated, vaporised, or taken orally.
No controlled human studies exist. What is known comes from seized-material analyses, a handful of intoxication and post-mortem case reports, and self-reported user accounts, all of which describe a potent, compulsive, short-acting stimulant with a high risk of redosing and sympathomimetic toxicity.
02 Mechanism
Functions as a norepinephrine-dopamine reuptake inhibitor (NDRI), raising synaptic catecholamines; the extended alkyl chain and pyrrolidine ring are characteristic of potent cathinone-type stimulants.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common (approximate, anecdotal) | 5–15 mg | Insufflated | User-reported ranges only; no validated dosing exists and potency varies between batches. |
| Common (approximate, anecdotal) | 10–25 mg | Oral | Slower onset; redosing strongly discouraged due to compulsion risk. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Stimulation and euphoriaUsers report intense energy, elevated mood and increased sociability lasting a few hours. | Marked but short-lived | Anecdotal | |
| Compulsive redosingRapid offset drives repeated administration, a hallmark of pyrrolidinophenone cathinones. | Strong | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Sympathomimetic cardiovascular toxicityTachycardia, hypertension, chest pain and arrhythmia reported in intoxication cases. | Severe | Common at higher/repeated doses | Anecdotal | |
| Stimulant psychosis and agitationParanoia, hallucinations and severe insomnia reported during binges. | Severe | Common with heavy/prolonged use | Anecdotal |