alpha-Pyrrolidinohexiophenone (also known as α-PiHP, a-PHiP, and 4-methyl-alpha-pyrrolidinopentanophenone) is a lesser-known novel stimulant substance of the cathinone and pyrrolidinophenone classes. It is structurally related to MDPV and A-PHP and is one of the latest successors to the designer drug cathinone analog A-PVP.

Users taking this substance note subjective effects of euphoria, thought acceleration, disinhibition and ego inflation. Generally, it comes in the form of either a fine powder or crystallized shards. It produces powerful but short-lived euphoric stimulant effects. Users report it to be more compulsive in nature (and strength) to vaporized methamphetamine. Like its cathinone predecessors, it is has gained notoriety for its tendency to induce compulsive redosing and addictive behaviors as well the ability to produce delusional states and psychosis when abused. The compulsivity induced in A-PiHP seems to be stronger compared to similar substances in this class, as reported by online anecdotal reports.

Very little data exists about the pharmacological properties, metabolism, and toxicity of α-PiHP. It has recently become commonly marketed as a legal, grey-market alternative to a-PHP, 3-MMC, and A-PVP. Also,  research chemical vendors commercially distribute it online.

It is highly advised to use harm reduction practices if using this substance.